| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Bob Liu | 2380 | 19.36% | 18 | 10.47% |
| Roger Pau Monné | 2223 | 18.08% | 12 | 6.98% |
| Jeremy Fitzhardinge | 2154 | 17.52% | 8 | 4.65% |
| Julien Grall | 1648 | 13.41% | 7 | 4.07% |
| Juergen Gross | 705 | 5.74% | 7 | 4.07% |
| Stefano Stabellini | 476 | 3.87% | 3 | 1.74% |
| Jan Beulich | 468 | 3.81% | 10 | 5.81% |
| Konrad Rzeszutek Wilk | 362 | 2.95% | 9 | 5.23% |
| Daniel Stodden | 362 | 2.95% | 8 | 4.65% |
| Christian Limpach | 195 | 1.59% | 2 | 1.16% |
| Chris Lalancette | 167 | 1.36% | 1 | 0.58% |
| Christoph Hellwig | 147 | 1.20% | 6 | 3.49% |
| Li Dongyang | 147 | 1.20% | 1 | 0.58% |
| Ian Campbell | 114 | 0.93% | 5 | 2.91% |
| Michael Christie | 102 | 0.83% | 3 | 1.74% |
| Vitaly Kuznetsov | 56 | 0.46% | 2 | 1.16% |
| K. Y. Srinivasan | 47 | 0.38% | 1 | 0.58% |
| Arnd Bergmann | 37 | 0.30% | 4 | 2.33% |
| Arianna Avanzini | 34 | 0.28% | 1 | 0.58% |
| Linus Torvalds | 34 | 0.28% | 2 | 1.16% |
| Bhavesh P. Davda | 33 | 0.27% | 1 | 0.58% |
| Jens Axboe | 33 | 0.27% | 4 | 2.33% |
| Markus Armbruster | 33 | 0.27% | 1 | 0.58% |
| Tejun Heo | 31 | 0.25% | 6 | 3.49% |
| Stefan Bader | 29 | 0.24% | 3 | 1.74% |
| David Vrabel | 28 | 0.23% | 2 | 1.16% |
| Dongli Zhang | 25 | 0.20% | 1 | 0.58% |
| Laszlo Ersek | 24 | 0.20% | 1 | 0.58% |
| Felipe Pena | 23 | 0.19% | 1 | 0.58% |
| Bart Van Assche | 19 | 0.15% | 5 | 2.91% |
| Al Viro | 18 | 0.15% | 2 | 1.16% |
| Greg Kroah-Hartman | 17 | 0.14% | 1 | 0.58% |
| Akinobu Mita | 11 | 0.09% | 1 | 0.58% |
| Mark McLoughlin | 10 | 0.08% | 2 | 1.16% |
| Kees Cook | 9 | 0.07% | 1 | 0.58% |
| Vasilis Liaskovitis | 8 | 0.07% | 1 | 0.58% |
| Dan J Williams | 8 | 0.07% | 1 | 0.58% |
| Steven Noonan | 7 | 0.06% | 1 | 0.58% |
| Noboru Iwamatsu | 6 | 0.05% | 1 | 0.58% |
| Manjunath Patil | 6 | 0.05% | 1 | 0.58% |
| Junxiao Bi | 5 | 0.04% | 1 | 0.58% |
| Andrew Jones | 5 | 0.04% | 1 | 0.58% |
| Kris Shannon | 4 | 0.03% | 1 | 0.58% |
| Wei Liu | 4 | 0.03% | 1 | 0.58% |
| Cathy Avery | 4 | 0.03% | 1 | 0.58% |
| Wim Colgate | 3 | 0.02% | 1 | 0.58% |
| Munehisa Kamata | 3 | 0.02% | 1 | 0.58% |
| Marc Olson | 3 | 0.02% | 1 | 0.58% |
| Joe Perches | 3 | 0.02% | 1 | 0.58% |
| Gustavo A. R. Silva | 2 | 0.02% | 1 | 0.58% |
| Balbir Singh | 2 | 0.02% | 1 | 0.58% |
| Olaf Hering | 2 | 0.02% | 1 | 0.58% |
| Hannes Reinecke | 2 | 0.02% | 1 | 0.58% |
| Thomas Meyer | 2 | 0.02% | 1 | 0.58% |
| Alexey Dobriyan | 2 | 0.02% | 1 | 0.58% |
| Eric Biggers | 1 | 0.01% | 1 | 0.58% |
| Peng Fan | 1 | 0.01% | 1 | 0.58% |
| Márton Németh | 1 | 0.01% | 1 | 0.58% |
| Harvey Harrison | 1 | 0.01% | 1 | 0.58% |
| Adrian Bunk | 1 | 0.01% | 1 | 0.58% |
| Ming Lei | 1 | 0.01% | 1 | 0.58% |
| Roel Kluin | 1 | 0.01% | 1 | 0.58% |
| Rasmus Villemoes | 1 | 0.01% | 1 | 0.58% |
| Owen Smith | 1 | 0.01% | 1 | 0.58% |
| Theodore Y. Ts'o | 1 | 0.01% | 1 | 0.58% |
| Total | 12292 | 172 |
/* * blkfront.c * * XenLinux virtual block device driver. * * Copyright (c) 2003-2004, Keir Fraser & Steve Hand * Modifications by Mark A. Williamson are (c) Intel Research Cambridge * Copyright (c) 2004, Christian Limpach * Copyright (c) 2004, Andrew Warfield * Copyright (c) 2005, Christopher Clark * Copyright (c) 2005, XenSource Ltd * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation; or, when distributed * separately from the Linux kernel or incorporated into other * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, modify, * merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #include <linux/interrupt.h> #include <linux/blkdev.h> #include <linux/blk-mq.h> #include <linux/hdreg.h> #include <linux/cdrom.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/mutex.h> #include <linux/scatterlist.h> #include <linux/bitmap.h> #include <linux/list.h> #include <linux/workqueue.h> #include <linux/sched/mm.h> #include <xen/xen.h> #include <xen/xenbus.h> #include <xen/grant_table.h> #include <xen/events.h> #include <xen/page.h> #include <xen/platform_pci.h> #include <xen/interface/grant_table.h> #include <xen/interface/io/blkif.h> #include <xen/interface/io/protocols.h> #include <asm/xen/hypervisor.h> /* * The minimal size of segment supported by the block framework is PAGE_SIZE. * When Linux is using a different page size than Xen, it may not be possible * to put all the data in a single segment. * This can happen when the backend doesn't support indirect descriptor and * therefore the maximum amount of data that a request can carry is * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE = 44KB * * Note that we only support one extra request. So the Linux page size * should be <= ( 2 * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) = * 88KB. */ #define HAS_EXTRA_REQ (BLKIF_MAX_SEGMENTS_PER_REQUEST < XEN_PFN_PER_PAGE) enum blkif_state { BLKIF_STATE_DISCONNECTED, BLKIF_STATE_CONNECTED, BLKIF_STATE_SUSPENDED, }; struct grant { grant_ref_t gref; struct page *page; struct list_head node; }; enum blk_req_status { REQ_WAITING, REQ_DONE, REQ_ERROR, REQ_EOPNOTSUPP, }; struct blk_shadow { struct blkif_request req; struct request *request; struct grant **grants_used; struct grant **indirect_grants; struct scatterlist *sg; unsigned int num_sg; enum blk_req_status status; #define NO_ASSOCIATED_ID ~0UL /* * Id of the sibling if we ever need 2 requests when handling a * block I/O request */ unsigned long associated_id; }; struct blkif_req { blk_status_t error; }; static inline struct blkif_req *blkif_req(struct request *rq) { return blk_mq_rq_to_pdu(rq); } static DEFINE_MUTEX(blkfront_mutex); static const struct block_device_operations xlvbd_block_fops; static struct delayed_work blkfront_work; static LIST_HEAD(info_list); /* * Maximum number of segments in indirect requests, the actual value used by * the frontend driver is the minimum of this value and the value provided * by the backend driver. */ static unsigned int xen_blkif_max_segments = 32; module_param_named(max_indirect_segments, xen_blkif_max_segments, uint, 0444); MODULE_PARM_DESC(max_indirect_segments, "Maximum amount of segments in indirect requests (default is 32)"); static unsigned int xen_blkif_max_queues = 4; module_param_named(max_queues, xen_blkif_max_queues, uint, 0444); MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used per virtual disk"); /* * Maximum order of pages to be used for the shared ring between front and * backend, 4KB page granularity is used. */ static unsigned int xen_blkif_max_ring_order; module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, 0444); MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring"); #define BLK_RING_SIZE(info) \ __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages) /* * ring-ref%u i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19 * characters are enough. Define to 20 to keep consistent with backend. */ #define RINGREF_NAME_LEN (20) /* * queue-%u would take 7 + 10(UINT_MAX) = 17 characters. */ #define QUEUE_NAME_LEN (17) /* * Per-ring info. * Every blkfront device can associate with one or more blkfront_ring_info, * depending on how many hardware queues/rings to be used. */ struct blkfront_ring_info { /* Lock to protect data in every ring buffer. */ spinlock_t ring_lock; struct blkif_front_ring ring; unsigned int ring_ref[XENBUS_MAX_RING_GRANTS]; unsigned int evtchn, irq; struct work_struct work; struct gnttab_free_callback callback; struct list_head indirect_pages; struct list_head grants; unsigned int persistent_gnts_c; unsigned long shadow_free; struct blkfront_info *dev_info; struct blk_shadow shadow[]; }; /* * We have one of these per vbd, whether ide, scsi or 'other'. They * hang in private_data off the gendisk structure. We may end up * putting all kinds of interesting stuff here :-) */ struct blkfront_info { struct mutex mutex; struct xenbus_device *xbdev; struct gendisk *gd; u16 sector_size; unsigned int physical_sector_size; int vdevice; blkif_vdev_t handle; enum blkif_state connected; /* Number of pages per ring buffer. */ unsigned int nr_ring_pages; struct request_queue *rq; unsigned int feature_flush:1; unsigned int feature_fua:1; unsigned int feature_discard:1; unsigned int feature_secdiscard:1; unsigned int feature_persistent:1; unsigned int discard_granularity; unsigned int discard_alignment; /* Number of 4KB segments handled */ unsigned int max_indirect_segments; int is_ready; struct blk_mq_tag_set tag_set; struct blkfront_ring_info *rinfo; unsigned int nr_rings; unsigned int rinfo_size; /* Save uncomplete reqs and bios for migration. */ struct list_head requests; struct bio_list bio_list; struct list_head info_list; }; static unsigned int nr_minors; static unsigned long *minors; static DEFINE_SPINLOCK(minor_lock); #define GRANT_INVALID_REF 0 #define PARTS_PER_DISK 16 #define PARTS_PER_EXT_DISK 256 #define BLKIF_MAJOR(dev) ((dev)>>8) #define BLKIF_MINOR(dev) ((dev) & 0xff) #define EXT_SHIFT 28 #define EXTENDED (1<<EXT_SHIFT) #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED)) #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED)) #define EMULATED_HD_DISK_MINOR_OFFSET (0) #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256) #define EMULATED_SD_DISK_MINOR_OFFSET (0) #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256) #define DEV_NAME "xvd" /* name in /dev */ /* * Grants are always the same size as a Xen page (i.e 4KB). * A physical segment is always the same size as a Linux page. * Number of grants per physical segment */ #define GRANTS_PER_PSEG (PAGE_SIZE / XEN_PAGE_SIZE) #define GRANTS_PER_INDIRECT_FRAME \ (XEN_PAGE_SIZE / sizeof(struct blkif_request_segment)) #define INDIRECT_GREFS(_grants) \ DIV_ROUND_UP(_grants, GRANTS_PER_INDIRECT_FRAME) static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo); static void blkfront_gather_backend_features(struct blkfront_info *info); static int negotiate_mq(struct blkfront_info *info); #define for_each_rinfo(info, ptr, idx) \ for ((ptr) = (info)->rinfo, (idx) = 0; \ (idx) < (info)->nr_rings; \ (idx)++, (ptr) = (void *)(ptr) + (info)->rinfo_size) static inline struct blkfront_ring_info * get_rinfo(const struct blkfront_info *info, unsigned int i) { BUG_ON(i >= info->nr_rings); return (void *)info->rinfo + i * info->rinfo_size; } static int get_id_from_freelist(struct blkfront_ring_info *rinfo) { unsigned long free = rinfo->shadow_free; BUG_ON(free >= BLK_RING_SIZE(rinfo->dev_info)); rinfo->shadow_free = rinfo->shadow[free].req.u.rw.id; rinfo->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */ return free; } static int add_id_to_freelist(struct blkfront_ring_info *rinfo, unsigned long id) { if (rinfo->shadow[id].req.u.rw.id != id) return -EINVAL; if (rinfo->shadow[id].request == NULL) return -EINVAL; rinfo->shadow[id].req.u.rw.id = rinfo->shadow_free; rinfo->shadow[id].request = NULL; rinfo->shadow_free = id; return 0; } static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) { struct blkfront_info *info = rinfo->dev_info; struct page *granted_page; struct grant *gnt_list_entry, *n; int i = 0; while (i < num) { gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO); if (!gnt_list_entry) goto out_of_memory; if (info->feature_persistent) { granted_page = alloc_page(GFP_NOIO); if (!granted_page) { kfree(gnt_list_entry); goto out_of_memory; } gnt_list_entry->page = granted_page; } gnt_list_entry->gref = GRANT_INVALID_REF; list_add(&gnt_list_entry->node, &rinfo->grants); i++; } return 0; out_of_memory: list_for_each_entry_safe(gnt_list_entry, n, &rinfo->grants, node) { list_del(&gnt_list_entry->node); if (info->feature_persistent) __free_page(gnt_list_entry->page); kfree(gnt_list_entry); i--; } BUG_ON(i != 0); return -ENOMEM; } static struct grant *get_free_grant(struct blkfront_ring_info *rinfo) { struct grant *gnt_list_entry; BUG_ON(list_empty(&rinfo->grants)); gnt_list_entry = list_first_entry(&rinfo->grants, struct grant, node); list_del(&gnt_list_entry->node); if (gnt_list_entry->gref != GRANT_INVALID_REF) rinfo->persistent_gnts_c--; return gnt_list_entry; } static inline void grant_foreign_access(const struct grant *gnt_list_entry, const struct blkfront_info *info) { gnttab_page_grant_foreign_access_ref_one(gnt_list_entry->gref, info->xbdev->otherend_id, gnt_list_entry->page, 0); } static struct grant *get_grant(grant_ref_t *gref_head, unsigned long gfn, struct blkfront_ring_info *rinfo) { struct grant *gnt_list_entry = get_free_grant(rinfo); struct blkfront_info *info = rinfo->dev_info; if (gnt_list_entry->gref != GRANT_INVALID_REF) return gnt_list_entry; /* Assign a gref to this page */ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); if (info->feature_persistent) grant_foreign_access(gnt_list_entry, info); else { /* Grant access to the GFN passed by the caller */ gnttab_grant_foreign_access_ref(gnt_list_entry->gref, info->xbdev->otherend_id, gfn, 0); } return gnt_list_entry; } static struct grant *get_indirect_grant(grant_ref_t *gref_head, struct blkfront_ring_info *rinfo) { struct grant *gnt_list_entry = get_free_grant(rinfo); struct blkfront_info *info = rinfo->dev_info; if (gnt_list_entry->gref != GRANT_INVALID_REF) return gnt_list_entry; /* Assign a gref to this page */ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); if (!info->feature_persistent) { struct page *indirect_page; /* Fetch a pre-allocated page to use for indirect grefs */ BUG_ON(list_empty(&rinfo->indirect_pages)); indirect_page = list_first_entry(&rinfo->indirect_pages, struct page, lru); list_del(&indirect_page->lru); gnt_list_entry->page = indirect_page; } grant_foreign_access(gnt_list_entry, info); return gnt_list_entry; } static const char *op_name(int op) { static const char *const names[] = { [BLKIF_OP_READ] = "read", [BLKIF_OP_WRITE] = "write", [BLKIF_OP_WRITE_BARRIER] = "barrier", [BLKIF_OP_FLUSH_DISKCACHE] = "flush", [BLKIF_OP_DISCARD] = "discard" }; if (op < 0 || op >= ARRAY_SIZE(names)) return "unknown"; if (!names[op]) return "reserved"; return names[op]; } static int xlbd_reserve_minors(unsigned int minor, unsigned int nr) { unsigned int end = minor + nr; int rc; if (end > nr_minors) { unsigned long *bitmap, *old; bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap), GFP_KERNEL); if (bitmap == NULL) return -ENOMEM; spin_lock(&minor_lock); if (end > nr_minors) { old = minors; memcpy(bitmap, minors, BITS_TO_LONGS(nr_minors) * sizeof(*bitmap)); minors = bitmap; nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG; } else old = bitmap; spin_unlock(&minor_lock); kfree(old); } spin_lock(&minor_lock); if (find_next_bit(minors, end, minor) >= end) { bitmap_set(minors, minor, nr); rc = 0; } else rc = -EBUSY; spin_unlock(&minor_lock); return rc; } static void xlbd_release_minors(unsigned int minor, unsigned int nr) { unsigned int end = minor + nr; BUG_ON(end > nr_minors); spin_lock(&minor_lock); bitmap_clear(minors, minor, nr); spin_unlock(&minor_lock); } static void blkif_restart_queue_callback(void *arg) { struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)arg; schedule_work(&rinfo->work); } static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg) { /* We don't have real geometry info, but let's at least return values consistent with the size of the device */ sector_t nsect = get_capacity(bd->bd_disk); sector_t cylinders = nsect; hg->heads = 0xff; hg->sectors = 0x3f; sector_div(cylinders, hg->heads * hg->sectors); hg->cylinders = cylinders; if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect) hg->cylinders = 0xffff; return 0; } static int blkif_ioctl(struct block_device *bdev, fmode_t mode, unsigned command, unsigned long argument) { struct blkfront_info *info = bdev->bd_disk->private_data; int i; dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n", command, (long)argument); switch (command) { case CDROMMULTISESSION: dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n"); for (i = 0; i < sizeof(struct cdrom_multisession); i++) if (put_user(0, (char __user *)(argument + i))) return -EFAULT; return 0; case CDROM_GET_CAPABILITY: { struct gendisk *gd = info->gd; if (gd->flags & GENHD_FL_CD) return 0; return -EINVAL; } default: /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n", command);*/ return -EINVAL; /* same return as native Linux */ } return 0; } static unsigned long blkif_ring_get_request(struct blkfront_ring_info *rinfo, struct request *req, struct blkif_request **ring_req) { unsigned long id; *ring_req = RING_GET_REQUEST(&rinfo->ring, rinfo->ring.req_prod_pvt); rinfo->ring.req_prod_pvt++; id = get_id_from_freelist(rinfo); rinfo->shadow[id].request = req; rinfo->shadow[id].status = REQ_WAITING; rinfo->shadow[id].associated_id = NO_ASSOCIATED_ID; (*ring_req)->u.rw.id = id; return id; } static int blkif_queue_discard_req(struct request *req, struct blkfront_ring_info *rinfo) { struct blkfront_info *info = rinfo->dev_info; struct blkif_request *ring_req; unsigned long id; /* Fill out a communications ring structure. */ id = blkif_ring_get_request(rinfo, req, &ring_req); ring_req->operation = BLKIF_OP_DISCARD; ring_req->u.discard.nr_sectors = blk_rq_sectors(req); ring_req->u.discard.id = id; ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req); if (req_op(req) == REQ_OP_SECURE_ERASE && info->feature_secdiscard) ring_req->u.discard.flag = BLKIF_DISCARD_SECURE; else ring_req->u.discard.flag = 0; /* Keep a private copy so we can reissue requests when recovering. */ rinfo->shadow[id].req = *ring_req; return 0; } struct setup_rw_req { unsigned int grant_idx; struct blkif_request_segment *segments; struct blkfront_ring_info *rinfo; struct blkif_request *ring_req; grant_ref_t gref_head; unsigned int id; /* Only used when persistent grant is used and it's a read request */ bool need_copy; unsigned int bvec_off; char *bvec_data; bool require_extra_req; struct blkif_request *extra_ring_req; }; static void blkif_setup_rw_req_grant(unsigned long gfn, unsigned int offset, unsigned int len, void *data) { struct setup_rw_req *setup = data; int n, ref; struct grant *gnt_list_entry; unsigned int fsect, lsect; /* Convenient aliases */ unsigned int grant_idx = setup->grant_idx; struct blkif_request *ring_req = setup->ring_req; struct blkfront_ring_info *rinfo = setup->rinfo; /* * We always use the shadow of the first request to store the list * of grant associated to the block I/O request. This made the * completion more easy to handle even if the block I/O request is * split. */ struct blk_shadow *shadow = &rinfo->shadow[setup->id]; if (unlikely(setup->require_extra_req && grant_idx >= BLKIF_MAX_SEGMENTS_PER_REQUEST)) { /* * We are using the second request, setup grant_idx * to be the index of the segment array. */ grant_idx -= BLKIF_MAX_SEGMENTS_PER_REQUEST; ring_req = setup->extra_ring_req; } if ((ring_req->operation == BLKIF_OP_INDIRECT) && (grant_idx % GRANTS_PER_INDIRECT_FRAME == 0)) { if (setup->segments) kunmap_atomic(setup->segments); n = grant_idx / GRANTS_PER_INDIRECT_FRAME; gnt_list_entry = get_indirect_grant(&setup->gref_head, rinfo); shadow->indirect_grants[n] = gnt_list_entry; setup->segments = kmap_atomic(gnt_list_entry->page); ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; } gnt_list_entry = get_grant(&setup->gref_head, gfn, rinfo); ref = gnt_list_entry->gref; /* * All the grants are stored in the shadow of the first * request. Therefore we have to use the global index. */ shadow->grants_used[setup->grant_idx] = gnt_list_entry; if (setup->need_copy) { void *shared_data; shared_data = kmap_atomic(gnt_list_entry->page); /* * this does not wipe data stored outside the * range sg->offset..sg->offset+sg->length. * Therefore, blkback *could* see data from * previous requests. This is OK as long as * persistent grants are shared with just one * domain. It may need refactoring if this * changes */ memcpy(shared_data + offset, setup->bvec_data + setup->bvec_off, len); kunmap_atomic(shared_data); setup->bvec_off += len; } fsect = offset >> 9; lsect = fsect + (len >> 9) - 1; if (ring_req->operation != BLKIF_OP_INDIRECT) { ring_req->u.rw.seg[grant_idx] = (struct blkif_request_segment) { .gref = ref, .first_sect = fsect, .last_sect = lsect }; } else { setup->segments[grant_idx % GRANTS_PER_INDIRECT_FRAME] = (struct blkif_request_segment) { .gref = ref, .first_sect = fsect, .last_sect = lsect }; } (setup->grant_idx)++; } static void blkif_setup_extra_req(struct blkif_request *first, struct blkif_request *second) { uint16_t nr_segments = first->u.rw.nr_segments; /* * The second request is only present when the first request uses * all its segments. It's always the continuity of the first one. */ first->u.rw.nr_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; second->u.rw.nr_segments = nr_segments - BLKIF_MAX_SEGMENTS_PER_REQUEST; second->u.rw.sector_number = first->u.rw.sector_number + (BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) / 512; second->u.rw.handle = first->u.rw.handle; second->operation = first->operation; } static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *rinfo) { struct blkfront_info *info = rinfo->dev_info; struct blkif_request *ring_req, *extra_ring_req = NULL; unsigned long id, extra_id = NO_ASSOCIATED_ID; bool require_extra_req = false; int i; struct setup_rw_req setup = { .grant_idx = 0, .segments = NULL, .rinfo = rinfo, .need_copy = rq_data_dir(req) && info->feature_persistent, }; /* * Used to store if we are able to queue the request by just using * existing persistent grants, or if we have to get new grants, * as there are not sufficiently many free. */ bool new_persistent_gnts = false; struct scatterlist *sg; int num_sg, max_grefs, num_grant; max_grefs = req->nr_phys_segments * GRANTS_PER_PSEG; if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST) /* * If we are using indirect segments we need to account * for the indirect grefs used in the request. */ max_grefs += INDIRECT_GREFS(max_grefs); /* Check if we have enough persistent grants to allocate a requests */ if (rinfo->persistent_gnts_c < max_grefs) { new_persistent_gnts = true; if (gnttab_alloc_grant_references( max_grefs - rinfo->persistent_gnts_c, &setup.gref_head) < 0) { gnttab_request_free_callback( &rinfo->callback, blkif_restart_queue_callback, rinfo, max_grefs - rinfo->persistent_gnts_c); return 1; } } /* Fill out a communications ring structure. */ id = blkif_ring_get_request(rinfo, req, &ring_req); num_sg = blk_rq_map_sg(req->q, req, rinfo->shadow[id].sg); num_grant = 0; /* Calculate the number of grant used */ for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i) num_grant += gnttab_count_grant(sg->offset, sg->length); require_extra_req = info->max_indirect_segments == 0 && num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST; BUG_ON(!HAS_EXTRA_REQ && require_extra_req); rinfo->shadow[id].num_sg = num_sg; if (num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST && likely(!require_extra_req)) { /* * The indirect operation can only be a BLKIF_OP_READ or * BLKIF_OP_WRITE */ BUG_ON(req_op(req) == REQ_OP_FLUSH || req->cmd_flags & REQ_FUA); ring_req->operation = BLKIF_OP_INDIRECT; ring_req->u.indirect.indirect_op = rq_data_dir(req) ? BLKIF_OP_WRITE : BLKIF_OP_READ; ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req); ring_req->u.indirect.handle = info->handle; ring_req->u.indirect.nr_segments = num_grant; } else { ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req); ring_req->u.rw.handle = info->handle; ring_req->operation = rq_data_dir(req) ? BLKIF_OP_WRITE : BLKIF_OP_READ; if (req_op(req) == REQ_OP_FLUSH || req->cmd_flags & REQ_FUA) { /* * Ideally we can do an unordered flush-to-disk. * In case the backend onlysupports barriers, use that. * A barrier request a superset of FUA, so we can * implement it the same way. (It's also a FLUSH+FUA, * since it is guaranteed ordered WRT previous writes.) */ if (info->feature_flush && info->feature_fua) ring_req->operation = BLKIF_OP_WRITE_BARRIER; else if (info->feature_flush) ring_req->operation = BLKIF_OP_FLUSH_DISKCACHE; else ring_req->operation = 0; } ring_req->u.rw.nr_segments = num_grant; if (unlikely(require_extra_req)) { extra_id = blkif_ring_get_request(rinfo, req, &extra_ring_req); /* * Only the first request contains the scatter-gather * list. */ rinfo->shadow[extra_id].num_sg = 0; blkif_setup_extra_req(ring_req, extra_ring_req); /* Link the 2 requests together */ rinfo->shadow[extra_id].associated_id = id; rinfo->shadow[id].associated_id = extra_id; } } setup.ring_req = ring_req; setup.id = id; setup.require_extra_req = require_extra_req; if (unlikely(require_extra_req)) setup.extra_ring_req = extra_ring_req; for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i) { BUG_ON(sg->offset + sg->length > PAGE_SIZE); if (setup.need_copy) { setup.bvec_off = sg->offset; setup.bvec_data = kmap_atomic(sg_page(sg)); } gnttab_foreach_grant_in_range(sg_page(sg), sg->offset, sg->length, blkif_setup_rw_req_grant, &setup); if (setup.need_copy) kunmap_atomic(setup.bvec_data); } if (setup.segments) kunmap_atomic(setup.segments); /* Keep a private copy so we can reissue requests when recovering. */ rinfo->shadow[id].req = *ring_req; if (unlikely(require_extra_req)) rinfo->shadow[extra_id].req = *extra_ring_req; if (new_persistent_gnts) gnttab_free_grant_references(setup.gref_head); return 0; } /* * Generate a Xen blkfront IO request from a blk layer request. Reads * and writes are handled as expected. * * @req: a request struct */ static int blkif_queue_request(struct request *req, struct blkfront_ring_info *rinfo) { if (unlikely(rinfo->dev_info->connected != BLKIF_STATE_CONNECTED)) return 1; if (unlikely(req_op(req) == REQ_OP_DISCARD || req_op(req) == REQ_OP_SECURE_ERASE)) return blkif_queue_discard_req(req, rinfo); else return blkif_queue_rw_req(req, rinfo); } static inline void flush_requests(struct blkfront_ring_info *rinfo) { int notify; RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&rinfo->ring, notify); if (notify) notify_remote_via_irq(rinfo->irq); } static inline bool blkif_request_flush_invalid(struct request *req, struct blkfront_info *info) { return (blk_rq_is_passthrough(req) || ((req_op(req) == REQ_OP_FLUSH) && !info->feature_flush) || ((req->cmd_flags & REQ_FUA) && !info->feature_fua)); } static blk_status_t blkif_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *qd) { unsigned long flags; int qid = hctx->queue_num; struct blkfront_info *info = hctx->queue->queuedata; struct blkfront_ring_info *rinfo = NULL; rinfo = get_rinfo(info, qid); blk_mq_start_request(qd->rq); spin_lock_irqsave(&rinfo->ring_lock, flags); if (RING_FULL(&rinfo->ring)) goto out_busy; if (blkif_request_flush_invalid(qd->rq, rinfo->dev_info)) goto out_err; if (blkif_queue_request(qd->rq, rinfo)) goto out_busy; flush_requests(rinfo); spin_unlock_irqrestore(&rinfo->ring_lock, flags); return BLK_STS_OK; out_err: spin_unlock_irqrestore(&rinfo->ring_lock, flags); return BLK_STS_IOERR; out_busy: blk_mq_stop_hw_queue(hctx); spin_unlock_irqrestore(&rinfo->ring_lock, flags); return BLK_STS_DEV_RESOURCE; } static void blkif_complete_rq(struct request *rq) { blk_mq_end_request(rq, blkif_req(rq)->error); } static const struct blk_mq_ops blkfront_mq_ops = { .queue_rq = blkif_queue_rq, .complete = blkif_complete_rq, }; static void blkif_set_queue_limits(struct blkfront_info *info) { struct request_queue *rq = info->rq; struct gendisk *gd = info->gd; unsigned int segments = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST; blk_queue_flag_set(QUEUE_FLAG_VIRT, rq); if (info->feature_discard) { blk_queue_flag_set(QUEUE_FLAG_DISCARD, rq); blk_queue_max_discard_sectors(rq, get_capacity(gd)); rq->limits.discard_granularity = info->discard_granularity; rq->limits.discard_alignment = info->discard_alignment; if (info->feature_secdiscard) blk_queue_flag_set(QUEUE_FLAG_SECERASE, rq); } /* Hard sector size and max sectors impersonate the equiv. hardware. */ blk_queue_logical_block_size(rq, info->sector_size); blk_queue_physical_block_size(rq, info->physical_sector_size); blk_queue_max_hw_sectors(rq, (segments * XEN_PAGE_SIZE) / 512); /* Each segment in a request is up to an aligned page in size. */ blk_queue_segment_boundary(rq, PAGE_SIZE - 1); blk_queue_max_segment_size(rq, PAGE_SIZE); /* Ensure a merged request will fit in a single I/O ring slot. */ blk_queue_max_segments(rq, segments / GRANTS_PER_PSEG); /* Make sure buffer addresses are sector-aligned. */ blk_queue_dma_alignment(rq, 511); } static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size, unsigned int physical_sector_size) { struct request_queue *rq; struct blkfront_info *info = gd->private_data; memset(&info->tag_set, 0, sizeof(info->tag_set)); info->tag_set.ops = &blkfront_mq_ops; info->tag_set.nr_hw_queues = info->nr_rings; if (HAS_EXTRA_REQ && info->max_indirect_segments == 0) { /* * When indirect descriptior is not supported, the I/O request * will be split between multiple request in the ring. * To avoid problems when sending the request, divide by * 2 the depth of the queue. */ info->tag_set.queue_depth = BLK_RING_SIZE(info) / 2; } else info->tag_set.queue_depth = BLK_RING_SIZE(info); info->tag_set.numa_node = NUMA_NO_NODE; info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; info->tag_set.cmd_size = sizeof(struct blkif_req); info->tag_set.driver_data = info; if (blk_mq_alloc_tag_set(&info->tag_set)) return -EINVAL; rq = blk_mq_init_queue(&info->tag_set); if (IS_ERR(rq)) { blk_mq_free_tag_set(&info->tag_set); return PTR_ERR(rq); } rq->queuedata = info; info->rq = gd->queue = rq; info->gd = gd; info->sector_size = sector_size; info->physical_sector_size = physical_sector_size; blkif_set_queue_limits(info); return 0; } static const char *flush_info(struct blkfront_info *info) { if (info->feature_flush && info->feature_fua) return "barrier: enabled;"; else if (info->feature_flush) return "flush diskcache: enabled;"; else return "barrier or flush: disabled;"; } static void xlvbd_flush(struct blkfront_info *info) { blk_queue_write_cache(info->rq, info->feature_flush ? true : false, info->feature_fua ? true : false); pr_info("blkfront: %s: %s %s %s %s %s\n", info->gd->disk_name, flush_info(info), "persistent grants:", info->feature_persistent ? "enabled;" : "disabled;", "indirect descriptors:", info->max_indirect_segments ? "enabled;" : "disabled;"); } static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) { int major; major = BLKIF_MAJOR(vdevice); *minor = BLKIF_MINOR(vdevice); switch (major) { case XEN_IDE0_MAJOR: *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET; *minor = ((*minor / 64) * PARTS_PER_DISK) + EMULATED_HD_DISK_MINOR_OFFSET; break; case XEN_IDE1_MAJOR: *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET; *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) + EMULATED_HD_DISK_MINOR_OFFSET; break; case XEN_SCSI_DISK0_MAJOR: *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET; *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET; break; case XEN_SCSI_DISK1_MAJOR: case XEN_SCSI_DISK2_MAJOR: case XEN_SCSI_DISK3_MAJOR: case XEN_SCSI_DISK4_MAJOR: case XEN_SCSI_DISK5_MAJOR: case XEN_SCSI_DISK6_MAJOR: case XEN_SCSI_DISK7_MAJOR: *offset = (*minor / PARTS_PER_DISK) + ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) + EMULATED_SD_DISK_NAME_OFFSET; *minor = *minor + ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) + EMULATED_SD_DISK_MINOR_OFFSET; break; case XEN_SCSI_DISK8_MAJOR: case XEN_SCSI_DISK9_MAJOR: case XEN_SCSI_DISK10_MAJOR: case XEN_SCSI_DISK11_MAJOR: case XEN_SCSI_DISK12_MAJOR: case XEN_SCSI_DISK13_MAJOR: case XEN_SCSI_DISK14_MAJOR: case XEN_SCSI_DISK15_MAJOR: *offset = (*minor / PARTS_PER_DISK) + ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) + EMULATED_SD_DISK_NAME_OFFSET; *minor = *minor + ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) + EMULATED_SD_DISK_MINOR_OFFSET; break; case XENVBD_MAJOR: *offset = *minor / PARTS_PER_DISK; break; default: printk(KERN_WARNING "blkfront: your disk configuration is " "incorrect, please use an xvd device instead\n"); return -ENODEV; } return 0; } static char *encode_disk_name(char *ptr, unsigned int n) { if (n >= 26) ptr = encode_disk_name(ptr, n / 26 - 1); *ptr = 'a' + n % 26; return ptr + 1; } static int xlvbd_alloc_gendisk(blkif_sector_t capacity, struct blkfront_info *info, u16 vdisk_info, u16 sector_size, unsigned int physical_sector_size) { struct gendisk *gd; int nr_minors = 1; int err; unsigned int offset; int minor; int nr_parts; char *ptr; BUG_ON(info->gd != NULL); BUG_ON(info->rq != NULL); if ((info->vdevice>>EXT_SHIFT) > 1) { /* this is above the extended range; something is wrong */ printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice); return -ENODEV; } if (!VDEV_IS_EXTENDED(info->vdevice)) { err = xen_translate_vdev(info->vdevice, &minor, &offset); if (err) return err; nr_parts = PARTS_PER_DISK; } else { minor = BLKIF_MINOR_EXT(info->vdevice); nr_parts = PARTS_PER_EXT_DISK; offset = minor / nr_parts; if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4) printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with " "emulated IDE disks,\n\t choose an xvd device name" "from xvde on\n", info->vdevice); } if (minor >> MINORBITS) { pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n", info->vdevice, minor); return -ENODEV; } if ((minor % nr_parts) == 0) nr_minors = nr_parts; err = xlbd_reserve_minors(minor, nr_minors); if (err) goto out; err = -ENODEV; gd = alloc_disk(nr_minors); if (gd == NULL) goto release; strcpy(gd->disk_name, DEV_NAME); ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset); BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN); if (nr_minors > 1) *ptr = 0; else snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr, "%d", minor & (nr_parts - 1)); gd->major = XENVBD_MAJOR; gd->first_minor = minor; gd->fops = &xlvbd_block_fops; gd->private_data = info; set_capacity(gd, capacity); if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size)) { del_gendisk(gd); goto release; } xlvbd_flush(info); if (vdisk_info & VDISK_READONLY) set_disk_ro(gd, 1); if (vdisk_info & VDISK_REMOVABLE) gd->flags |= GENHD_FL_REMOVABLE; if (vdisk_info & VDISK_CDROM) gd->flags |= GENHD_FL_CD; return 0; release: xlbd_release_minors(minor, nr_minors); out: return err; } static void xlvbd_release_gendisk(struct blkfront_info *info) { unsigned int minor, nr_minors, i; struct blkfront_ring_info *rinfo; if (info->rq == NULL) return; /* No more blkif_request(). */ blk_mq_stop_hw_queues(info->rq); for_each_rinfo(info, rinfo, i) { /* No more gnttab callback work. */ gnttab_cancel_free_callback(&rinfo->callback); /* Flush gnttab callback work. Must be done with no locks held. */ flush_work(&rinfo->work); } del_gendisk(info->gd); minor = info->gd->first_minor; nr_minors = info->gd->minors; xlbd_release_minors(minor, nr_minors); blk_cleanup_queue(info->rq); blk_mq_free_tag_set(&info->tag_set); info->rq = NULL; put_disk(info->gd); info->gd = NULL; } /* Already hold rinfo->ring_lock. */ static inline void kick_pending_request_queues_locked(struct blkfront_ring_info *rinfo) { if (!RING_FULL(&rinfo->ring)) blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true); } static void kick_pending_request_queues(struct blkfront_ring_info *rinfo) { unsigned long flags; spin_lock_irqsave(&rinfo->ring_lock, flags); kick_pending_request_queues_locked(rinfo); spin_unlock_irqrestore(&rinfo->ring_lock, flags); } static void blkif_restart_queue(struct work_struct *work) { struct blkfront_ring_info *rinfo = container_of(work, struct blkfront_ring_info, work); if (rinfo->dev_info->connected == BLKIF_STATE_CONNECTED) kick_pending_request_queues(rinfo); } static void blkif_free_ring(struct blkfront_ring_info *rinfo) { struct grant *persistent_gnt, *n; struct blkfront_info *info = rinfo->dev_info; int i, j, segs; /* * Remove indirect pages, this only happens when using indirect * descriptors but not persistent grants */ if (!list_empty(&rinfo->indirect_pages)) { struct page *indirect_page, *n; BUG_ON(info->feature_persistent); list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) { list_del(&indirect_page->lru); __free_page(indirect_page); } } /* Remove all persistent grants. */ if (!list_empty(&rinfo->grants)) { list_for_each_entry_safe(persistent_gnt, n, &rinfo->grants, node) { list_del(&persistent_gnt->node); if (persistent_gnt->gref != GRANT_INVALID_REF) { gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); rinfo->persistent_gnts_c--; } if (info->feature_persistent) __free_page(persistent_gnt->page); kfree(persistent_gnt); } } BUG_ON(rinfo->persistent_gnts_c != 0); for (i = 0; i < BLK_RING_SIZE(info); i++) { /* * Clear persistent grants present in requests already * on the shared ring */ if (!rinfo->shadow[i].request) goto free_shadow; segs = rinfo->shadow[i].req.operation == BLKIF_OP_INDIRECT ? rinfo->shadow[i].req.u.indirect.nr_segments : rinfo->shadow[i].req.u.rw.nr_segments; for (j = 0; j < segs; j++) { persistent_gnt = rinfo->shadow[i].grants_used[j]; gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); if (info->feature_persistent) __free_page(persistent_gnt->page); kfree(persistent_gnt); } if (rinfo->shadow[i].req.operation != BLKIF_OP_INDIRECT) /* * If this is not an indirect operation don't try to * free indirect segments */ goto free_shadow; for (j = 0; j < INDIRECT_GREFS(segs); j++) { persistent_gnt = rinfo->shadow[i].indirect_grants[j]; gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); __free_page(persistent_gnt->page); kfree(persistent_gnt); } free_shadow: kvfree(rinfo->shadow[i].grants_used); rinfo->shadow[i].grants_used = NULL; kvfree(rinfo->shadow[i].indirect_grants); rinfo->shadow[i].indirect_grants = NULL; kvfree(rinfo->shadow[i].sg); rinfo->shadow[i].sg = NULL; } /* No more gnttab callback work. */ gnttab_cancel_free_callback(&rinfo->callback); /* Flush gnttab callback work. Must be done with no locks held. */ flush_work(&rinfo->work); /* Free resources associated with old device channel. */ for (i = 0; i < info->nr_ring_pages; i++) { if (rinfo->ring_ref[i] != GRANT_INVALID_REF) { gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0); rinfo->ring_ref[i] = GRANT_INVALID_REF; } } free_pages((unsigned long)rinfo->ring.sring, get_order(info->nr_ring_pages * XEN_PAGE_SIZE)); rinfo->ring.sring = NULL; if (rinfo->irq) unbind_from_irqhandler(rinfo->irq, rinfo); rinfo->evtchn = rinfo->irq = 0; } static void blkif_free(struct blkfront_info *info, int suspend) { unsigned int i; struct blkfront_ring_info *rinfo; /* Prevent new requests being issued until we fix things up. */ info->connected = suspend ? BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; /* No more blkif_request(). */ if (info->rq) blk_mq_stop_hw_queues(info->rq); for_each_rinfo(info, rinfo, i) blkif_free_ring(rinfo); kvfree(info->rinfo); info->rinfo = NULL; info->nr_rings = 0; } struct copy_from_grant { const struct blk_shadow *s; unsigned int grant_idx; unsigned int bvec_offset; char *bvec_data; }; static void blkif_copy_from_grant(unsigned long gfn, unsigned int offset, unsigned int len, void *data) { struct copy_from_grant *info = data; char *shared_data; /* Convenient aliases */ const struct blk_shadow *s = info->s; shared_data = kmap_atomic(s->grants_used[info->grant_idx]->page); memcpy(info->bvec_data + info->bvec_offset, shared_data + offset, len); info->bvec_offset += len; info->grant_idx++; kunmap_atomic(shared_data); } static enum blk_req_status blkif_rsp_to_req_status(int rsp) { switch (rsp) { case BLKIF_RSP_OKAY: return REQ_DONE; case BLKIF_RSP_EOPNOTSUPP: return REQ_EOPNOTSUPP; case BLKIF_RSP_ERROR: /* Fallthrough. */ default: return REQ_ERROR; } } /* * Get the final status of the block request based on two ring response */ static int blkif_get_final_status(enum blk_req_status s1, enum blk_req_status s2) { BUG_ON(s1 == REQ_WAITING); BUG_ON(s2 == REQ_WAITING); if (s1 == REQ_ERROR || s2 == REQ_ERROR) return BLKIF_RSP_ERROR; else if (s1 == REQ_EOPNOTSUPP || s2 == REQ_EOPNOTSUPP) return BLKIF_RSP_EOPNOTSUPP; return BLKIF_RSP_OKAY; } static bool blkif_completion(unsigned long *id, struct blkfront_ring_info *rinfo, struct blkif_response *bret) { int i = 0; struct scatterlist *sg; int num_sg, num_grant; struct blkfront_info *info = rinfo->dev_info; struct blk_shadow *s = &rinfo->shadow[*id]; struct copy_from_grant data = { .grant_idx = 0, }; num_grant = s->req.operation == BLKIF_OP_INDIRECT ? s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments; /* The I/O request may be split in two. */ if (unlikely(s->associated_id != NO_ASSOCIATED_ID)) { struct blk_shadow *s2 = &rinfo->shadow[s->associated_id]; /* Keep the status of the current response in shadow. */ s->status = blkif_rsp_to_req_status(bret->status); /* Wait the second response if not yet here. */ if (s2->status == REQ_WAITING) return false; bret->status = blkif_get_final_status(s->status, s2->status); /* * All the grants is stored in the first shadow in order * to make the completion code simpler. */ num_grant += s2->req.u.rw.nr_segments; /* * The two responses may not come in order. Only the * first request will store the scatter-gather list. */ if (s2->num_sg != 0) { /* Update "id" with the ID of the first response. */ *id = s->associated_id; s = s2; } /* * We don't need anymore the second request, so recycling * it now. */ if (add_id_to_freelist(rinfo, s->associated_id)) WARN(1, "%s: can't recycle the second part (id = %ld) of the request\n", info->gd->disk_name, s->associated_id); } data.s = s; num_sg = s->num_sg; if (bret->operation == BLKIF_OP_READ && info->feature_persistent) { for_each_sg(s->sg, sg, num_sg, i) { BUG_ON(sg->offset + sg->length > PAGE_SIZE); data.bvec_offset = sg->offset; data.bvec_data = kmap_atomic(sg_page(sg)); gnttab_foreach_grant_in_range(sg_page(sg), sg->offset, sg->length, blkif_copy_from_grant, &data); kunmap_atomic(data.bvec_data); } } /* Add the persistent grant into the list of free grants */ for (i = 0; i < num_grant; i++) { if (gnttab_query_foreign_access(s->grants_used[i]->gref)) { /* * If the grant is still mapped by the backend (the * backend has chosen to make this grant persistent) * we add it at the head of the list, so it will be * reused first. */ if (!info->feature_persistent) pr_alert_ratelimited("backed has not unmapped grant: %u\n", s->grants_used[i]->gref); list_add(&s->grants_used[i]->node, &rinfo->grants); rinfo->persistent_gnts_c++; } else { /* * If the grant is not mapped by the backend we end the * foreign access and add it to the tail of the list, * so it will not be picked again unless we run out of * persistent grants. */ gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL); s->grants_used[i]->gref = GRANT_INVALID_REF; list_add_tail(&s->grants_used[i]->node, &rinfo->grants); } } if (s->req.operation == BLKIF_OP_INDIRECT) { for (i = 0; i < INDIRECT_GREFS(num_grant); i++) { if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) { if (!info->feature_persistent) pr_alert_ratelimited("backed has not unmapped grant: %u\n", s->indirect_grants[i]->gref); list_add(&s->indirect_grants[i]->node, &rinfo->grants); rinfo->persistent_gnts_c++; } else { struct page *indirect_page; gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL); /* * Add the used indirect page back to the list of * available pages for indirect grefs. */ if (!info->feature_persistent) { indirect_page = s->indirect_grants[i]->page; list_add(&indirect_page->lru, &rinfo->indirect_pages); } s->indirect_grants[i]->gref = GRANT_INVALID_REF; list_add_tail(&s->indirect_grants[i]->node, &rinfo->grants); } } } return true; } static irqreturn_t blkif_interrupt(int irq, void *dev_id) { struct request *req; struct blkif_response *bret; RING_IDX i, rp; unsigned long flags; struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)dev_id; struct blkfront_info *info = rinfo->dev_info; if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) return IRQ_HANDLED; spin_lock_irqsave(&rinfo->ring_lock, flags); again: rp = rinfo->ring.sring->rsp_prod; rmb(); /* Ensure we see queued responses up to 'rp'. */ for (i = rinfo->ring.rsp_cons; i != rp; i++) { unsigned long id; bret = RING_GET_RESPONSE(&rinfo->ring, i); id = bret->id; /* * The backend has messed up and given us an id that we would * never have given to it (we stamp it up to BLK_RING_SIZE - * look in get_id_from_freelist. */ if (id >= BLK_RING_SIZE(info)) { WARN(1, "%s: response to %s has incorrect id (%ld)\n", info->gd->disk_name, op_name(bret->operation), id); /* We can't safely get the 'struct request' as * the id is busted. */ continue; } req = rinfo->shadow[id].request; if (bret->operation != BLKIF_OP_DISCARD) { /* * We may need to wait for an extra response if the * I/O request is split in 2 */ if (!blkif_completion(&id, rinfo, bret)) continue; } if (add_id_to_freelist(rinfo, id)) { WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n", info->gd->disk_name, op_name(bret->operation), id); continue; } if (bret->status == BLKIF_RSP_OKAY) blkif_req(req)->error = BLK_STS_OK; else blkif_req(req)->error = BLK_STS_IOERR; switch (bret->operation) { case BLKIF_OP_DISCARD: if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { struct request_queue *rq = info->rq; printk(KERN_WARNING "blkfront: %s: %s op failed\n", info->gd->disk_name, op_name(bret->operation)); blkif_req(req)->error = BLK_STS_NOTSUPP; info->feature_discard = 0; info->feature_secdiscard = 0; blk_queue_flag_clear(QUEUE_FLAG_DISCARD, rq); blk_queue_flag_clear(QUEUE_FLAG_SECERASE, rq); } break; case BLKIF_OP_FLUSH_DISKCACHE: case BLKIF_OP_WRITE_BARRIER: if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { printk(KERN_WARNING "blkfront: %s: %s op failed\n", info->gd->disk_name, op_name(bret->operation)); blkif_req(req)->error = BLK_STS_NOTSUPP; } if (unlikely(bret->status == BLKIF_RSP_ERROR && rinfo->shadow[id].req.u.rw.nr_segments == 0)) { printk(KERN_WARNING "blkfront: %s: empty %s op failed\n", info->gd->disk_name, op_name(bret->operation)); blkif_req(req)->error = BLK_STS_NOTSUPP; } if (unlikely(blkif_req(req)->error)) { if (blkif_req(req)->error == BLK_STS_NOTSUPP) blkif_req(req)->error = BLK_STS_OK; info->feature_fua = 0; info->feature_flush = 0; xlvbd_flush(info); } /* fall through */ case BLKIF_OP_READ: case BLKIF_OP_WRITE: if (unlikely(bret->status != BLKIF_RSP_OKAY)) dev_dbg(&info->xbdev->dev, "Bad return from blkdev data " "request: %x\n", bret->status); break; default: BUG(); } blk_mq_complete_request(req); } rinfo->ring.rsp_cons = i; if (i != rinfo->ring.req_prod_pvt) { int more_to_do; RING_FINAL_CHECK_FOR_RESPONSES(&rinfo->ring, more_to_do); if (more_to_do) goto again; } else rinfo->ring.sring->rsp_event = i + 1; kick_pending_request_queues_locked(rinfo); spin_unlock_irqrestore(&rinfo->ring_lock, flags); return IRQ_HANDLED; } static int setup_blkring(struct xenbus_device *dev, struct blkfront_ring_info *rinfo) { struct blkif_sring *sring; int err, i; struct blkfront_info *info = rinfo->dev_info; unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE; grant_ref_t gref[XENBUS_MAX_RING_GRANTS]; for (i = 0; i < info->nr_ring_pages; i++) rinfo->ring_ref[i] = GRANT_INVALID_REF; sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH, get_order(ring_size)); if (!sring) { xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); return -ENOMEM; } SHARED_RING_INIT(sring); FRONT_RING_INIT(&rinfo->ring, sring, ring_size); err = xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gref); if (err < 0) { free_pages((unsigned long)sring, get_order(ring_size)); rinfo->ring.sring = NULL; goto fail; } for (i = 0; i < info->nr_ring_pages; i++) rinfo->ring_ref[i] = gref[i]; err = xenbus_alloc_evtchn(dev, &rinfo->evtchn); if (err) goto fail; err = bind_evtchn_to_irqhandler(rinfo->evtchn, blkif_interrupt, 0, "blkif", rinfo); if (err <= 0) { xenbus_dev_fatal(dev, err, "bind_evtchn_to_irqhandler failed"); goto fail; } rinfo->irq = err; return 0; fail: blkif_free(info, 0); return err; } /* * Write out per-ring/queue nodes including ring-ref and event-channel, and each * ring buffer may have multi pages depending on ->nr_ring_pages. */ static int write_per_ring_nodes(struct xenbus_transaction xbt, struct blkfront_ring_info *rinfo, const char *dir) { int err; unsigned int i; const char *message = NULL; struct blkfront_info *info = rinfo->dev_info; if (info->nr_ring_pages == 1) { err = xenbus_printf(xbt, dir, "ring-ref", "%u", rinfo->ring_ref[0]); if (err) { message = "writing ring-ref"; goto abort_transaction; } } else { for (i = 0; i < info->nr_ring_pages; i++) { char ring_ref_name[RINGREF_NAME_LEN]; snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); err = xenbus_printf(xbt, dir, ring_ref_name, "%u", rinfo->ring_ref[i]); if (err) { message = "writing ring-ref"; goto abort_transaction; } } } err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn); if (err) { message = "writing event-channel"; goto abort_transaction; } return 0; abort_transaction: xenbus_transaction_end(xbt, 1); if (message) xenbus_dev_fatal(info->xbdev, err, "%s", message); return err; } static void free_info(struct blkfront_info *info) { list_del(&info->info_list); kfree(info); } /* Common code used when first setting up, and when resuming. */ static int talk_to_blkback(struct xenbus_device *dev, struct blkfront_info *info) { const char *message = NULL; struct xenbus_transaction xbt; int err; unsigned int i, max_page_order; unsigned int ring_page_order; struct blkfront_ring_info *rinfo; if (!info) return -ENODEV; max_page_order = xenbus_read_unsigned(info->xbdev->otherend, "max-ring-page-order", 0); ring_page_order = min(xen_blkif_max_ring_order, max_page_order); info->nr_ring_pages = 1 << ring_page_order; err = negotiate_mq(info); if (err) goto destroy_blkring; for_each_rinfo(info, rinfo, i) { /* Create shared ring, alloc event channel. */ err = setup_blkring(dev, rinfo); if (err) goto destroy_blkring; } again: err = xenbus_transaction_start(&xbt); if (err) { xenbus_dev_fatal(dev, err, "starting transaction"); goto destroy_blkring; } if (info->nr_ring_pages > 1) { err = xenbus_printf(xbt, dev->nodename, "ring-page-order", "%u", ring_page_order); if (err) { message = "writing ring-page-order"; goto abort_transaction; } } /* We already got the number of queues/rings in _probe */ if (info->nr_rings == 1) { err = write_per_ring_nodes(xbt, info->rinfo, dev->nodename); if (err) goto destroy_blkring; } else { char *path; size_t pathsize; err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues", "%u", info->nr_rings); if (err) { message = "writing multi-queue-num-queues"; goto abort_transaction; } pathsize = strlen(dev->nodename) + QUEUE_NAME_LEN; path = kmalloc(pathsize, GFP_KERNEL); if (!path) { err = -ENOMEM; message = "ENOMEM while writing ring references"; goto abort_transaction; } for_each_rinfo(info, rinfo, i) { memset(path, 0, pathsize); snprintf(path, pathsize, "%s/queue-%u", dev->nodename, i); err = write_per_ring_nodes(xbt, rinfo, path); if (err) { kfree(path); goto destroy_blkring; } } kfree(path); } err = xenbus_printf(xbt, dev->nodename, "protocol", "%s", XEN_IO_PROTO_ABI_NATIVE); if (err) { message = "writing protocol"; goto abort_transaction; } err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1); if (err) dev_warn(&dev->dev, "writing persistent grants feature to xenbus"); err = xenbus_transaction_end(xbt, 0); if (err) { if (err == -EAGAIN) goto again; xenbus_dev_fatal(dev, err, "completing transaction"); goto destroy_blkring; } for_each_rinfo(info, rinfo, i) { unsigned int j; for (j = 0; j < BLK_RING_SIZE(info); j++) rinfo->shadow[j].req.u.rw.id = j + 1; rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff; } xenbus_switch_state(dev, XenbusStateInitialised); return 0; abort_transaction: xenbus_transaction_end(xbt, 1); if (message) xenbus_dev_fatal(dev, err, "%s", message); destroy_blkring: blkif_free(info, 0); mutex_lock(&blkfront_mutex); free_info(info); mutex_unlock(&blkfront_mutex); dev_set_drvdata(&dev->dev, NULL); return err; } static int negotiate_mq(struct blkfront_info *info) { unsigned int backend_max_queues; unsigned int i; struct blkfront_ring_info *rinfo; BUG_ON(info->nr_rings); /* Check if backend supports multiple queues. */ backend_max_queues = xenbus_read_unsigned(info->xbdev->otherend, "multi-queue-max-queues", 1); info->nr_rings = min(backend_max_queues, xen_blkif_max_queues); /* We need at least one ring. */ if (!info->nr_rings) info->nr_rings = 1; info->rinfo_size = struct_size(info->rinfo, shadow, BLK_RING_SIZE(info)); info->rinfo = kvcalloc(info->nr_rings, info->rinfo_size, GFP_KERNEL); if (!info->rinfo) { xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure"); info->nr_rings = 0; return -ENOMEM; } for_each_rinfo(info, rinfo, i) { INIT_LIST_HEAD(&rinfo->indirect_pages); INIT_LIST_HEAD(&rinfo->grants); rinfo->dev_info = info; INIT_WORK(&rinfo->work, blkif_restart_queue); spin_lock_init(&rinfo->ring_lock); } return 0; } /** * Entry point to this code when a new device is created. Allocate the basic * structures and the ring buffer for communication with the backend, and * inform the backend of the appropriate details for those. Switch to * Initialised state. */ static int blkfront_probe(struct xenbus_device *dev, const struct xenbus_device_id *id) { int err, vdevice; struct blkfront_info *info; /* FIXME: Use dynamic device id if this is not set. */ err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device", "%i", &vdevice); if (err != 1) { /* go looking in the extended area instead */ err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext", "%i", &vdevice); if (err != 1) { xenbus_dev_fatal(dev, err, "reading virtual-device"); return err; } } if (xen_hvm_domain()) { char *type; int len; /* no unplug has been done: do not hook devices != xen vbds */ if (xen_has_pv_and_legacy_disk_devices()) { int major; if (!VDEV_IS_EXTENDED(vdevice)) major = BLKIF_MAJOR(vdevice); else major = XENVBD_MAJOR; if (major != XENVBD_MAJOR) { printk(KERN_INFO "%s: HVM does not support vbd %d as xen block device\n", __func__, vdevice); return -ENODEV; } } /* do not create a PV cdrom device if we are an HVM guest */ type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len); if (IS_ERR(type)) return -ENODEV; if (strncmp(type, "cdrom", 5) == 0) { kfree(type); return -ENODEV; } kfree(type); } info = kzalloc(sizeof(*info), GFP_KERNEL); if (!info) { xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure"); return -ENOMEM; } info->xbdev = dev; mutex_init(&info->mutex); info->vdevice = vdevice; info->connected = BLKIF_STATE_DISCONNECTED; /* Front end dir is a number, which is used as the id. */ info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0); dev_set_drvdata(&dev->dev, info); mutex_lock(&blkfront_mutex); list_add(&info->info_list, &info_list); mutex_unlock(&blkfront_mutex); return 0; } static int blkif_recover(struct blkfront_info *info) { unsigned int r_index; struct request *req, *n; int rc; struct bio *bio; unsigned int segs; struct blkfront_ring_info *rinfo; blkfront_gather_backend_features(info); /* Reset limits changed by blk_mq_update_nr_hw_queues(). */ blkif_set_queue_limits(info); segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST; blk_queue_max_segments(info->rq, segs / GRANTS_PER_PSEG); for_each_rinfo(info, rinfo, r_index) { rc = blkfront_setup_indirect(rinfo); if (rc) return rc; } xenbus_switch_state(info->xbdev, XenbusStateConnected); /* Now safe for us to use the shared ring */ info->connected = BLKIF_STATE_CONNECTED; for_each_rinfo(info, rinfo, r_index) { /* Kick any other new requests queued since we resumed */ kick_pending_request_queues(rinfo); } list_for_each_entry_safe(req, n, &info->requests, queuelist) { /* Requeue pending requests (flush or discard) */ list_del_init(&req->queuelist); BUG_ON(req->nr_phys_segments > segs); blk_mq_requeue_request(req, false); } blk_mq_start_stopped_hw_queues(info->rq, true); blk_mq_kick_requeue_list(info->rq); while ((bio = bio_list_pop(&info->bio_list)) != NULL) { /* Traverse the list of pending bios and re-queue them */ submit_bio(bio); } return 0; } /** * We are reconnecting to the backend, due to a suspend/resume, or a backend * driver restart. We tear down our blkif structure and recreate it, but * leave the device-layer structures intact so that this is transparent to the * rest of the kernel. */ static int blkfront_resume(struct xenbus_device *dev) { struct blkfront_info *info = dev_get_drvdata(&dev->dev); int err = 0; unsigned int i, j; struct blkfront_ring_info *rinfo; dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename); bio_list_init(&info->bio_list); INIT_LIST_HEAD(&info->requests); for_each_rinfo(info, rinfo, i) { struct bio_list merge_bio; struct blk_shadow *shadow = rinfo->shadow; for (j = 0; j < BLK_RING_SIZE(info); j++) { /* Not in use? */ if (!shadow[j].request) continue; /* * Get the bios in the request so we can re-queue them. */ if (req_op(shadow[j].request) == REQ_OP_FLUSH || req_op(shadow[j].request) == REQ_OP_DISCARD || req_op(shadow[j].request) == REQ_OP_SECURE_ERASE || shadow[j].request->cmd_flags & REQ_FUA) { /* * Flush operations don't contain bios, so * we need to requeue the whole request * * XXX: but this doesn't make any sense for a * write with the FUA flag set.. */ list_add(&shadow[j].request->queuelist, &info->requests); continue; } merge_bio.head = shadow[j].request->bio; merge_bio.tail = shadow[j].request->biotail; bio_list_merge(&info->bio_list, &merge_bio); shadow[j].request->bio = NULL; blk_mq_end_request(shadow[j].request, BLK_STS_OK); } } blkif_free(info, info->connected == BLKIF_STATE_CONNECTED); err = talk_to_blkback(dev, info); if (!err) blk_mq_update_nr_hw_queues(&info->tag_set, info->nr_rings); /* * We have to wait for the backend to switch to * connected state, since we want to read which * features it supports. */ return err; } static void blkfront_closing(struct blkfront_info *info) { struct xenbus_device *xbdev = info->xbdev; struct block_device *bdev = NULL; mutex_lock(&info->mutex); if (xbdev->state == XenbusStateClosing) { mutex_unlock(&info->mutex); return; } if (info->gd) bdev = bdget_disk(info->gd, 0); mutex_unlock(&info->mutex); if (!bdev) { xenbus_frontend_closed(xbdev); return; } mutex_lock(&bdev->bd_mutex); if (bdev->bd_openers) { xenbus_dev_error(xbdev, -EBUSY, "Device in use; refusing to close"); xenbus_switch_state(xbdev, XenbusStateClosing); } else { xlvbd_release_gendisk(info); xenbus_frontend_closed(xbdev); } mutex_unlock(&bdev->bd_mutex); bdput(bdev); } static void blkfront_setup_discard(struct blkfront_info *info) { int err; unsigned int discard_granularity; unsigned int discard_alignment; info->feature_discard = 1; err = xenbus_gather(XBT_NIL, info->xbdev->otherend, "discard-granularity", "%u", &discard_granularity, "discard-alignment", "%u", &discard_alignment, NULL); if (!err) { info->discard_granularity = discard_granularity; info->discard_alignment = discard_alignment; } info->feature_secdiscard = !!xenbus_read_unsigned(info->xbdev->otherend, "discard-secure", 0); } static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) { unsigned int psegs, grants, memflags; int err, i; struct blkfront_info *info = rinfo->dev_info; memflags = memalloc_noio_save(); if (info->max_indirect_segments == 0) { if (!HAS_EXTRA_REQ) grants = BLKIF_MAX_SEGMENTS_PER_REQUEST; else { /* * When an extra req is required, the maximum * grants supported is related to the size of the * Linux block segment. */ grants = GRANTS_PER_PSEG; } } else grants = info->max_indirect_segments; psegs = DIV_ROUND_UP(grants, GRANTS_PER_PSEG); err = fill_grant_buffer(rinfo, (grants + INDIRECT_GREFS(grants)) * BLK_RING_SIZE(info)); if (err) goto out_of_memory; if (!info->feature_persistent && info->max_indirect_segments) { /* * We are using indirect descriptors but not persistent * grants, we need to allocate a set of pages that can be * used for mapping indirect grefs */ int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info); BUG_ON(!list_empty(&rinfo->indirect_pages)); for (i = 0; i < num; i++) { struct page *indirect_page = alloc_page(GFP_KERNEL); if (!indirect_page) goto out_of_memory; list_add(&indirect_page->lru, &rinfo->indirect_pages); } } for (i = 0; i < BLK_RING_SIZE(info); i++) { rinfo->shadow[i].grants_used = kvcalloc(grants, sizeof(rinfo->shadow[i].grants_used[0]), GFP_KERNEL); rinfo->shadow[i].sg = kvcalloc(psegs, sizeof(rinfo->shadow[i].sg[0]), GFP_KERNEL); if (info->max_indirect_segments) rinfo->shadow[i].indirect_grants = kvcalloc(INDIRECT_GREFS(grants), sizeof(rinfo->shadow[i].indirect_grants[0]), GFP_KERNEL); if ((rinfo->shadow[i].grants_used == NULL) || (rinfo->shadow[i].sg == NULL) || (info->max_indirect_segments && (rinfo->shadow[i].indirect_grants == NULL))) goto out_of_memory; sg_init_table(rinfo->shadow[i].sg, psegs); } memalloc_noio_restore(memflags); return 0; out_of_memory: for (i = 0; i < BLK_RING_SIZE(info); i++) { kvfree(rinfo->shadow[i].grants_used); rinfo->shadow[i].grants_used = NULL; kvfree(rinfo->shadow[i].sg); rinfo->shadow[i].sg = NULL; kvfree(rinfo->shadow[i].indirect_grants); rinfo->shadow[i].indirect_grants = NULL; } if (!list_empty(&rinfo->indirect_pages)) { struct page *indirect_page, *n; list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) { list_del(&indirect_page->lru); __free_page(indirect_page); } } memalloc_noio_restore(memflags); return -ENOMEM; } /* * Gather all backend feature-* */ static void blkfront_gather_backend_features(struct blkfront_info *info) { unsigned int indirect_segments; info->feature_flush = 0; info->feature_fua = 0; /* * If there's no "feature-barrier" defined, then it means * we're dealing with a very old backend which writes * synchronously; nothing to do. * * If there are barriers, then we use flush. */ if (xenbus_read_unsigned(info->xbdev->otherend, "feature-barrier", 0)) { info->feature_flush = 1; info->feature_fua = 1; } /* * And if there is "feature-flush-cache" use that above * barriers. */ if (xenbus_read_unsigned(info->xbdev->otherend, "feature-flush-cache", 0)) { info->feature_flush = 1; info->feature_fua = 0; } if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0)) blkfront_setup_discard(info); info->feature_persistent = !!xenbus_read_unsigned(info->xbdev->otherend, "feature-persistent", 0); indirect_segments = xenbus_read_unsigned(info->xbdev->otherend, "feature-max-indirect-segments", 0); if (indirect_segments > xen_blkif_max_segments) indirect_segments = xen_blkif_max_segments; if (indirect_segments <= BLKIF_MAX_SEGMENTS_PER_REQUEST) indirect_segments = 0; info->max_indirect_segments = indirect_segments; if (info->feature_persistent) { mutex_lock(&blkfront_mutex); schedule_delayed_work(&blkfront_work, HZ * 10); mutex_unlock(&blkfront_mutex); } } /* * Invoked when the backend is finally 'ready' (and has told produced * the details about the physical device - #sectors, size, etc). */ static void blkfront_connect(struct blkfront_info *info) { unsigned long long sectors; unsigned long sector_size; unsigned int physical_sector_size; unsigned int binfo; int err, i; struct blkfront_ring_info *rinfo; switch (info->connected) { case BLKIF_STATE_CONNECTED: /* * Potentially, the back-end may be signalling * a capacity change; update the capacity. */ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend, "sectors", "%Lu", §ors); if (XENBUS_EXIST_ERR(err)) return; printk(KERN_INFO "Setting capacity to %Lu\n", sectors); set_capacity_revalidate_and_notify(info->gd, sectors, true); return; case BLKIF_STATE_SUSPENDED: /* * If we are recovering from suspension, we need to wait * for the backend to announce it's features before * reconnecting, at least we need to know if the backend * supports indirect descriptors, and how many. */ blkif_recover(info); return; default: break; } dev_dbg(&info->xbdev->dev, "%s:%s.\n", __func__, info->xbdev->otherend); err = xenbus_gather(XBT_NIL, info->xbdev->otherend, "sectors", "%llu", §ors, "info", "%u", &binfo, "sector-size", "%lu", §or_size, NULL); if (err) { xenbus_dev_fatal(info->xbdev, err, "reading backend fields at %s", info->xbdev->otherend); return; } /* * physcial-sector-size is a newer field, so old backends may not * provide this. Assume physical sector size to be the same as * sector_size in that case. */ physical_sector_size = xenbus_read_unsigned(info->xbdev->otherend, "physical-sector-size", sector_size); blkfront_gather_backend_features(info); for_each_rinfo(info, rinfo, i) { err = blkfront_setup_indirect(rinfo); if (err) { xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s", info->xbdev->otherend); blkif_free(info, 0); break; } } err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size, physical_sector_size); if (err) { xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s", info->xbdev->otherend); goto fail; } xenbus_switch_state(info->xbdev, XenbusStateConnected); /* Kick pending requests. */ info->connected = BLKIF_STATE_CONNECTED; for_each_rinfo(info, rinfo, i) kick_pending_request_queues(rinfo); device_add_disk(&info->xbdev->dev, info->gd, NULL); info->is_ready = 1; return; fail: blkif_free(info, 0); return; } /** * Callback received when the backend's state changes. */ static void blkback_changed(struct xenbus_device *dev, enum xenbus_state backend_state) { struct blkfront_info *info = dev_get_drvdata(&dev->dev); dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state); switch (backend_state) { case XenbusStateInitWait: if (dev->state != XenbusStateInitialising) break; if (talk_to_blkback(dev, info)) break; case XenbusStateInitialising: case XenbusStateInitialised: case XenbusStateReconfiguring: case XenbusStateReconfigured: case XenbusStateUnknown: break; case XenbusStateConnected: /* * talk_to_blkback sets state to XenbusStateInitialised * and blkfront_connect sets it to XenbusStateConnected * (if connection went OK). * * If the backend (or toolstack) decides to poke at backend * state (and re-trigger the watch by setting the state repeatedly * to XenbusStateConnected (4)) we need to deal with this. * This is allowed as this is used to communicate to the guest * that the size of disk has changed! */ if ((dev->state != XenbusStateInitialised) && (dev->state != XenbusStateConnected)) { if (talk_to_blkback(dev, info)) break; } blkfront_connect(info); break; case XenbusStateClosed: if (dev->state == XenbusStateClosed) break; /* fall through */ case XenbusStateClosing: if (info) blkfront_closing(info); break; } } static int blkfront_remove(struct xenbus_device *xbdev) { struct blkfront_info *info = dev_get_drvdata(&xbdev->dev); struct block_device *bdev = NULL; struct gendisk *disk; dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename); if (!info) return 0; blkif_free(info, 0); mutex_lock(&info->mutex); disk = info->gd; if (disk) bdev = bdget_disk(disk, 0); info->xbdev = NULL; mutex_unlock(&info->mutex); if (!bdev) { mutex_lock(&blkfront_mutex); free_info(info); mutex_unlock(&blkfront_mutex); return 0; } /* * The xbdev was removed before we reached the Closed * state. See if it's safe to remove the disk. If the bdev * isn't closed yet, we let release take care of it. */ mutex_lock(&bdev->bd_mutex); info = disk->private_data; dev_warn(disk_to_dev(disk), "%s was hot-unplugged, %d stale handles\n", xbdev->nodename, bdev->bd_openers); if (info && !bdev->bd_openers) { xlvbd_release_gendisk(info); disk->private_data = NULL; mutex_lock(&blkfront_mutex); free_info(info); mutex_unlock(&blkfront_mutex); } mutex_unlock(&bdev->bd_mutex); bdput(bdev); return 0; } static int blkfront_is_ready(struct xenbus_device *dev) { struct blkfront_info *info = dev_get_drvdata(&dev->dev); return info->is_ready && info->xbdev; } static int blkif_open(struct block_device *bdev, fmode_t mode) { struct gendisk *disk = bdev->bd_disk; struct blkfront_info *info; int err = 0; mutex_lock(&blkfront_mutex); info = disk->private_data; if (!info) { /* xbdev gone */ err = -ERESTARTSYS; goto out; } mutex_lock(&info->mutex); if (!info->gd) /* xbdev is closed */ err = -ERESTARTSYS; mutex_unlock(&info->mutex); out: mutex_unlock(&blkfront_mutex); return err; } static void blkif_release(struct gendisk *disk, fmode_t mode) { struct blkfront_info *info = disk->private_data; struct block_device *bdev; struct xenbus_device *xbdev; mutex_lock(&blkfront_mutex); bdev = bdget_disk(disk, 0); if (!bdev) { WARN(1, "Block device %s yanked out from us!\n", disk->disk_name); goto out_mutex; } if (bdev->bd_openers) goto out; /* * Check if we have been instructed to close. We will have * deferred this request, because the bdev was still open. */ mutex_lock(&info->mutex); xbdev = info->xbdev; if (xbdev && xbdev->state == XenbusStateClosing) { /* pending switch to state closed */ dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n"); xlvbd_release_gendisk(info); xenbus_frontend_closed(info->xbdev); } mutex_unlock(&info->mutex); if (!xbdev) { /* sudden device removal */ dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n"); xlvbd_release_gendisk(info); disk->private_data = NULL; free_info(info); } out: bdput(bdev); out_mutex: mutex_unlock(&blkfront_mutex); } static const struct block_device_operations xlvbd_block_fops = { .owner = THIS_MODULE, .open = blkif_open, .release = blkif_release, .getgeo = blkif_getgeo, .ioctl = blkif_ioctl, .compat_ioctl = blkdev_compat_ptr_ioctl, }; static const struct xenbus_device_id blkfront_ids[] = { { "vbd" }, { "" } }; static struct xenbus_driver blkfront_driver = { .ids = blkfront_ids, .probe = blkfront_probe, .remove = blkfront_remove, .resume = blkfront_resume, .otherend_changed = blkback_changed, .is_ready = blkfront_is_ready, }; static void purge_persistent_grants(struct blkfront_info *info) { unsigned int i; unsigned long flags; struct blkfront_ring_info *rinfo; for_each_rinfo(info, rinfo, i) { struct grant *gnt_list_entry, *tmp; spin_lock_irqsave(&rinfo->ring_lock, flags); if (rinfo->persistent_gnts_c == 0) { spin_unlock_irqrestore(&rinfo->ring_lock, flags); continue; } list_for_each_entry_safe(gnt_list_entry, tmp, &rinfo->grants, node) { if (gnt_list_entry->gref == GRANT_INVALID_REF || gnttab_query_foreign_access(gnt_list_entry->gref)) continue; list_del(&gnt_list_entry->node); gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL); rinfo->persistent_gnts_c--; gnt_list_entry->gref = GRANT_INVALID_REF; list_add_tail(&gnt_list_entry->node, &rinfo->grants); } spin_unlock_irqrestore(&rinfo->ring_lock, flags); } } static void blkfront_delay_work(struct work_struct *work) { struct blkfront_info *info; bool need_schedule_work = false; mutex_lock(&blkfront_mutex); list_for_each_entry(info, &info_list, info_list) { if (info->feature_persistent) { need_schedule_work = true; mutex_lock(&info->mutex); purge_persistent_grants(info); mutex_unlock(&info->mutex); } } if (need_schedule_work) schedule_delayed_work(&blkfront_work, HZ * 10); mutex_unlock(&blkfront_mutex); } static int __init xlblk_init(void) { int ret; int nr_cpus = num_online_cpus(); if (!xen_domain()) return -ENODEV; if (!xen_has_pv_disk_devices()) return -ENODEV; if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) { pr_warn("xen_blk: can't get major %d with name %s\n", XENVBD_MAJOR, DEV_NAME); return -ENODEV; } if (xen_blkif_max_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST) xen_blkif_max_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) { pr_info("Invalid max_ring_order (%d), will use default max: %d.\n", xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER); xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER; } if (xen_blkif_max_queues > nr_cpus) { pr_info("Invalid max_queues (%d), will use default max: %d.\n", xen_blkif_max_queues, nr_cpus); xen_blkif_max_queues = nr_cpus; } INIT_DELAYED_WORK(&blkfront_work, blkfront_delay_work); ret = xenbus_register_frontend(&blkfront_driver); if (ret) { unregister_blkdev(XENVBD_MAJOR, DEV_NAME); return ret; } return 0; } module_init(xlblk_init); static void __exit xlblk_exit(void) { cancel_delayed_work_sync(&blkfront_work); xenbus_unregister_driver(&blkfront_driver); unregister_blkdev(XENVBD_MAJOR, DEV_NAME); kfree(minors); } module_exit(xlblk_exit); MODULE_DESCRIPTION("Xen virtual block device frontend"); MODULE_LICENSE("GPL"); MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR); MODULE_ALIAS("xen:vbd"); MODULE_ALIAS("xenblk");
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