| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Konrad Rzeszutek Wilk | 3468 | 64.02% | 26 | 22.41% |
| Bob Liu | 618 | 11.41% | 7 | 6.03% |
| Roger Pau Monné | 247 | 4.56% | 10 | 8.62% |
| Paul Durrant | 204 | 3.77% | 4 | 3.45% |
| SeongJae Park | 109 | 2.01% | 5 | 4.31% |
| Li Dongyang | 101 | 1.86% | 1 | 0.86% |
| Jan Beulich | 97 | 1.79% | 6 | 5.17% |
| Valentin Priescu | 69 | 1.27% | 1 | 0.86% |
| Tao Chen | 64 | 1.18% | 1 | 0.86% |
| Juergen Gross | 62 | 1.14% | 7 | 6.03% |
| Dongli Zhang | 55 | 1.02% | 2 | 1.72% |
| Christian Brauner | 50 | 0.92% | 1 | 0.86% |
| Jeremy Fitzhardinge | 45 | 0.83% | 4 | 3.45% |
| David Vrabel | 44 | 0.81% | 3 | 2.59% |
| Stefan Bader | 28 | 0.52% | 1 | 0.86% |
| Christoph Hellwig | 22 | 0.41% | 8 | 6.90% |
| Chris Lalancette | 21 | 0.39% | 1 | 0.86% |
| Annie Li | 20 | 0.37% | 1 | 0.86% |
| Olaf Hering | 10 | 0.18% | 1 | 0.86% |
| Wenwen Wang | 9 | 0.17% | 1 | 0.86% |
| Laszlo Ersek | 9 | 0.17% | 1 | 0.86% |
| Julien Grall | 7 | 0.13% | 2 | 1.72% |
| K. Y. Srinivasan | 7 | 0.13% | 1 | 0.86% |
| Zoltan Kiss | 7 | 0.13% | 1 | 0.86% |
| Keir Fraser | 6 | 0.11% | 1 | 0.86% |
| Pawel Wieczorkiewicz | 6 | 0.11% | 1 | 0.86% |
| Gustavo A. R. Silva | 4 | 0.07% | 2 | 1.72% |
| Wei Liu | 4 | 0.07% | 1 | 0.86% |
| Matthew Wilcox | 3 | 0.06% | 1 | 0.86% |
| Joe Perches | 3 | 0.06% | 2 | 1.72% |
| Kees Cook | 3 | 0.06% | 2 | 1.72% |
| Maximilian Heyne | 2 | 0.04% | 1 | 0.86% |
| Jens Axboe | 2 | 0.04% | 1 | 0.86% |
| Joe Jin | 2 | 0.04% | 1 | 0.86% |
| Vitaly Kuznetsov | 2 | 0.04% | 1 | 0.86% |
| Thomas Gleixner | 2 | 0.04% | 1 | 0.86% |
| Justin P. Mattock | 1 | 0.02% | 1 | 0.86% |
| Wei Yongjun | 1 | 0.02% | 1 | 0.86% |
| Bart Van Assche | 1 | 0.02% | 1 | 0.86% |
| Dawei Li | 1 | 0.02% | 1 | 0.86% |
| Jingoo Han | 1 | 0.02% | 1 | 0.86% |
| Total | 5417 | 116 |
// SPDX-License-Identifier: GPL-2.0-or-later /* Xenbus code for blkif backend Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au> Copyright (C) 2005 XenSource Ltd */ #define pr_fmt(fmt) "xen-blkback: " fmt #include <linux/module.h> #include <linux/kthread.h> #include <linux/pagemap.h> #include <xen/events.h> #include <xen/grant_table.h> #include "common.h" /* On the XenBus the max length of 'ring-ref%u'. */ #define RINGREF_NAME_LEN (20) struct backend_info { struct xenbus_device *dev; struct xen_blkif *blkif; struct xenbus_watch backend_watch; unsigned major; unsigned minor; char *mode; }; static struct kmem_cache *xen_blkif_cachep; static void connect(struct backend_info *); static int connect_ring(struct backend_info *); static void backend_changed(struct xenbus_watch *, const char *, const char *); static void xen_blkif_free(struct xen_blkif *blkif); static void xen_vbd_free(struct xen_vbd *vbd); struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) { return be->dev; } /* * The last request could free the device from softirq context and * xen_blkif_free() can sleep. */ static void xen_blkif_deferred_free(struct work_struct *work) { struct xen_blkif *blkif; blkif = container_of(work, struct xen_blkif, free_work); xen_blkif_free(blkif); } static int blkback_name(struct xen_blkif *blkif, char *buf) { char *devpath, *devname; struct xenbus_device *dev = blkif->be->dev; devpath = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL); if (IS_ERR(devpath)) return PTR_ERR(devpath); devname = strstr(devpath, "/dev/"); if (devname != NULL) devname += strlen("/dev/"); else devname = devpath; snprintf(buf, TASK_COMM_LEN, "%d.%s", blkif->domid, devname); kfree(devpath); return 0; } static void xen_update_blkif_status(struct xen_blkif *blkif) { int err; char name[TASK_COMM_LEN]; struct xen_blkif_ring *ring; int i; /* Not ready to connect? */ if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev_file) return; /* Already connected? */ if (blkif->be->dev->state == XenbusStateConnected) return; /* Attempt to connect: exit if we fail to. */ connect(blkif->be); if (blkif->be->dev->state != XenbusStateConnected) return; err = blkback_name(blkif, name); if (err) { xenbus_dev_error(blkif->be->dev, err, "get blkback dev name"); return; } err = sync_blockdev(file_bdev(blkif->vbd.bdev_file)); if (err) { xenbus_dev_error(blkif->be->dev, err, "block flush"); return; } invalidate_inode_pages2(blkif->vbd.bdev_file->f_mapping); for (i = 0; i < blkif->nr_rings; i++) { ring = &blkif->rings[i]; ring->xenblkd = kthread_run(xen_blkif_schedule, ring, "%s-%d", name, i); if (IS_ERR(ring->xenblkd)) { err = PTR_ERR(ring->xenblkd); ring->xenblkd = NULL; xenbus_dev_fatal(blkif->be->dev, err, "start %s-%d xenblkd", name, i); goto out; } } return; out: while (--i >= 0) { ring = &blkif->rings[i]; kthread_stop(ring->xenblkd); } return; } static int xen_blkif_alloc_rings(struct xen_blkif *blkif) { unsigned int r; blkif->rings = kcalloc(blkif->nr_rings, sizeof(struct xen_blkif_ring), GFP_KERNEL); if (!blkif->rings) return -ENOMEM; for (r = 0; r < blkif->nr_rings; r++) { struct xen_blkif_ring *ring = &blkif->rings[r]; spin_lock_init(&ring->blk_ring_lock); init_waitqueue_head(&ring->wq); INIT_LIST_HEAD(&ring->pending_free); INIT_LIST_HEAD(&ring->persistent_purge_list); INIT_WORK(&ring->persistent_purge_work, xen_blkbk_unmap_purged_grants); gnttab_page_cache_init(&ring->free_pages); spin_lock_init(&ring->pending_free_lock); init_waitqueue_head(&ring->pending_free_wq); init_waitqueue_head(&ring->shutdown_wq); ring->blkif = blkif; ring->st_print = jiffies; ring->active = true; } return 0; } /* Enable the persistent grants feature. */ static bool feature_persistent = true; module_param(feature_persistent, bool, 0644); MODULE_PARM_DESC(feature_persistent, "Enables the persistent grants feature"); static struct xen_blkif *xen_blkif_alloc(domid_t domid) { struct xen_blkif *blkif; BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL); if (!blkif) return ERR_PTR(-ENOMEM); blkif->domid = domid; atomic_set(&blkif->refcnt, 1); init_completion(&blkif->drain_complete); /* * Because freeing back to the cache may be deferred, it is not * safe to unload the module (and hence destroy the cache) until * this has completed. To prevent premature unloading, take an * extra module reference here and release only when the object * has been freed back to the cache. */ __module_get(THIS_MODULE); INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); return blkif; } static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, unsigned int nr_grefs, unsigned int evtchn) { int err; struct xen_blkif *blkif = ring->blkif; const struct blkif_common_sring *sring_common; RING_IDX rsp_prod, req_prod; unsigned int size; /* Already connected through? */ if (ring->irq) return 0; err = xenbus_map_ring_valloc(blkif->be->dev, gref, nr_grefs, &ring->blk_ring); if (err < 0) return err; sring_common = (struct blkif_common_sring *)ring->blk_ring; rsp_prod = READ_ONCE(sring_common->rsp_prod); req_prod = READ_ONCE(sring_common->req_prod); switch (blkif->blk_protocol) { case BLKIF_PROTOCOL_NATIVE: { struct blkif_sring *sring_native = (struct blkif_sring *)ring->blk_ring; BACK_RING_ATTACH(&ring->blk_rings.native, sring_native, rsp_prod, XEN_PAGE_SIZE * nr_grefs); size = __RING_SIZE(sring_native, XEN_PAGE_SIZE * nr_grefs); break; } case BLKIF_PROTOCOL_X86_32: { struct blkif_x86_32_sring *sring_x86_32 = (struct blkif_x86_32_sring *)ring->blk_ring; BACK_RING_ATTACH(&ring->blk_rings.x86_32, sring_x86_32, rsp_prod, XEN_PAGE_SIZE * nr_grefs); size = __RING_SIZE(sring_x86_32, XEN_PAGE_SIZE * nr_grefs); break; } case BLKIF_PROTOCOL_X86_64: { struct blkif_x86_64_sring *sring_x86_64 = (struct blkif_x86_64_sring *)ring->blk_ring; BACK_RING_ATTACH(&ring->blk_rings.x86_64, sring_x86_64, rsp_prod, XEN_PAGE_SIZE * nr_grefs); size = __RING_SIZE(sring_x86_64, XEN_PAGE_SIZE * nr_grefs); break; } default: BUG(); } err = -EIO; if (req_prod - rsp_prod > size) goto fail; err = bind_interdomain_evtchn_to_irqhandler_lateeoi(blkif->be->dev, evtchn, xen_blkif_be_int, 0, "blkif-backend", ring); if (err < 0) goto fail; ring->irq = err; return 0; fail: xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); ring->blk_rings.common.sring = NULL; return err; } static int xen_blkif_disconnect(struct xen_blkif *blkif) { struct pending_req *req, *n; unsigned int j, r; bool busy = false; for (r = 0; r < blkif->nr_rings; r++) { struct xen_blkif_ring *ring = &blkif->rings[r]; unsigned int i = 0; if (!ring->active) continue; if (ring->xenblkd) { kthread_stop(ring->xenblkd); ring->xenblkd = NULL; wake_up(&ring->shutdown_wq); } /* The above kthread_stop() guarantees that at this point we * don't have any discard_io or other_io requests. So, checking * for inflight IO is enough. */ if (atomic_read(&ring->inflight) > 0) { busy = true; continue; } if (ring->irq) { unbind_from_irqhandler(ring->irq, ring); ring->irq = 0; } if (ring->blk_rings.common.sring) { xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); ring->blk_rings.common.sring = NULL; } /* Remove all persistent grants and the cache of ballooned pages. */ xen_blkbk_free_caches(ring); /* Check that there is no request in use */ list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { list_del(&req->free_list); for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) kfree(req->segments[j]); for (j = 0; j < MAX_INDIRECT_PAGES; j++) kfree(req->indirect_pages[j]); kfree(req); i++; } BUG_ON(atomic_read(&ring->persistent_gnt_in_use) != 0); BUG_ON(!list_empty(&ring->persistent_purge_list)); BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts)); BUG_ON(ring->free_pages.num_pages != 0); BUG_ON(ring->persistent_gnt_c != 0); WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages)); ring->active = false; } if (busy) return -EBUSY; blkif->nr_ring_pages = 0; /* * blkif->rings was allocated in connect_ring, so we should free it in * here. */ kfree(blkif->rings); blkif->rings = NULL; blkif->nr_rings = 0; return 0; } static void xen_blkif_free(struct xen_blkif *blkif) { WARN_ON(xen_blkif_disconnect(blkif)); xen_vbd_free(&blkif->vbd); kfree(blkif->be->mode); kfree(blkif->be); /* Make sure everything is drained before shutting down */ kmem_cache_free(xen_blkif_cachep, blkif); module_put(THIS_MODULE); } int __init xen_blkif_interface_init(void) { xen_blkif_cachep = kmem_cache_create("blkif_cache", sizeof(struct xen_blkif), 0, 0, NULL); if (!xen_blkif_cachep) return -ENOMEM; return 0; } void xen_blkif_interface_fini(void) { kmem_cache_destroy(xen_blkif_cachep); xen_blkif_cachep = NULL; } /* * sysfs interface for VBD I/O requests */ #define VBD_SHOW_ALLRING(name, format) \ static ssize_t show_##name(struct device *_dev, \ struct device_attribute *attr, \ char *buf) \ { \ struct xenbus_device *dev = to_xenbus_device(_dev); \ struct backend_info *be = dev_get_drvdata(&dev->dev); \ struct xen_blkif *blkif = be->blkif; \ unsigned int i; \ unsigned long long result = 0; \ \ if (!blkif->rings) \ goto out; \ \ for (i = 0; i < blkif->nr_rings; i++) { \ struct xen_blkif_ring *ring = &blkif->rings[i]; \ \ result += ring->st_##name; \ } \ \ out: \ return sprintf(buf, format, result); \ } \ static DEVICE_ATTR(name, 0444, show_##name, NULL) VBD_SHOW_ALLRING(oo_req, "%llu\n"); VBD_SHOW_ALLRING(rd_req, "%llu\n"); VBD_SHOW_ALLRING(wr_req, "%llu\n"); VBD_SHOW_ALLRING(f_req, "%llu\n"); VBD_SHOW_ALLRING(ds_req, "%llu\n"); VBD_SHOW_ALLRING(rd_sect, "%llu\n"); VBD_SHOW_ALLRING(wr_sect, "%llu\n"); static struct attribute *xen_vbdstat_attrs[] = { &dev_attr_oo_req.attr, &dev_attr_rd_req.attr, &dev_attr_wr_req.attr, &dev_attr_f_req.attr, &dev_attr_ds_req.attr, &dev_attr_rd_sect.attr, &dev_attr_wr_sect.attr, NULL }; static const struct attribute_group xen_vbdstat_group = { .name = "statistics", .attrs = xen_vbdstat_attrs, }; #define VBD_SHOW(name, format, args...) \ static ssize_t show_##name(struct device *_dev, \ struct device_attribute *attr, \ char *buf) \ { \ struct xenbus_device *dev = to_xenbus_device(_dev); \ struct backend_info *be = dev_get_drvdata(&dev->dev); \ \ return sprintf(buf, format, ##args); \ } \ static DEVICE_ATTR(name, 0444, show_##name, NULL) VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); VBD_SHOW(mode, "%s\n", be->mode); static int xenvbd_sysfs_addif(struct xenbus_device *dev) { int error; error = device_create_file(&dev->dev, &dev_attr_physical_device); if (error) goto fail1; error = device_create_file(&dev->dev, &dev_attr_mode); if (error) goto fail2; error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group); if (error) goto fail3; return 0; fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); fail2: device_remove_file(&dev->dev, &dev_attr_mode); fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); return error; } static void xenvbd_sysfs_delif(struct xenbus_device *dev) { sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); device_remove_file(&dev->dev, &dev_attr_mode); device_remove_file(&dev->dev, &dev_attr_physical_device); } static void xen_vbd_free(struct xen_vbd *vbd) { if (vbd->bdev_file) fput(vbd->bdev_file); vbd->bdev_file = NULL; } static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, unsigned major, unsigned minor, int readonly, int cdrom) { struct xen_vbd *vbd; struct file *bdev_file; vbd = &blkif->vbd; vbd->handle = handle; vbd->readonly = readonly; vbd->type = 0; vbd->pdevice = MKDEV(major, minor); bdev_file = bdev_file_open_by_dev(vbd->pdevice, vbd->readonly ? BLK_OPEN_READ : BLK_OPEN_WRITE, NULL, NULL); if (IS_ERR(bdev_file)) { pr_warn("xen_vbd_create: device %08x could not be opened\n", vbd->pdevice); return -ENOENT; } vbd->bdev_file = bdev_file; if (file_bdev(vbd->bdev_file)->bd_disk == NULL) { pr_warn("xen_vbd_create: device %08x doesn't exist\n", vbd->pdevice); xen_vbd_free(vbd); return -ENOENT; } vbd->size = vbd_sz(vbd); if (cdrom || disk_to_cdi(file_bdev(vbd->bdev_file)->bd_disk)) vbd->type |= VDISK_CDROM; if (file_bdev(vbd->bdev_file)->bd_disk->flags & GENHD_FL_REMOVABLE) vbd->type |= VDISK_REMOVABLE; if (bdev_write_cache(file_bdev(bdev_file))) vbd->flush_support = true; if (bdev_max_secure_erase_sectors(file_bdev(bdev_file))) vbd->discard_secure = true; pr_debug("Successful creation of handle=%04x (dom=%u)\n", handle, blkif->domid); return 0; } static void xen_blkbk_remove(struct xenbus_device *dev) { struct backend_info *be = dev_get_drvdata(&dev->dev); pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); if (be->major || be->minor) xenvbd_sysfs_delif(dev); if (be->backend_watch.node) { unregister_xenbus_watch(&be->backend_watch); kfree(be->backend_watch.node); be->backend_watch.node = NULL; } dev_set_drvdata(&dev->dev, NULL); if (be->blkif) { xen_blkif_disconnect(be->blkif); /* Put the reference we set in xen_blkif_alloc(). */ xen_blkif_put(be->blkif); } } int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, struct backend_info *be, int state) { struct xenbus_device *dev = be->dev; int err; err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", "%d", state); if (err) dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err); return err; } static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be) { struct xenbus_device *dev = be->dev; struct xen_blkif *blkif = be->blkif; int err; int state = 0; struct block_device *bdev = file_bdev(be->blkif->vbd.bdev_file); if (!xenbus_read_unsigned(dev->nodename, "discard-enable", 1)) return; if (bdev_max_discard_sectors(bdev)) { err = xenbus_printf(xbt, dev->nodename, "discard-granularity", "%u", bdev_discard_granularity(bdev)); if (err) { dev_warn(&dev->dev, "writing discard-granularity (%d)", err); return; } err = xenbus_printf(xbt, dev->nodename, "discard-alignment", "%u", bdev_discard_alignment(bdev)); if (err) { dev_warn(&dev->dev, "writing discard-alignment (%d)", err); return; } state = 1; /* Optional. */ err = xenbus_printf(xbt, dev->nodename, "discard-secure", "%d", blkif->vbd.discard_secure); if (err) { dev_warn(&dev->dev, "writing discard-secure (%d)", err); return; } } err = xenbus_printf(xbt, dev->nodename, "feature-discard", "%d", state); if (err) dev_warn(&dev->dev, "writing feature-discard (%d)", err); } int xen_blkbk_barrier(struct xenbus_transaction xbt, struct backend_info *be, int state) { struct xenbus_device *dev = be->dev; int err; err = xenbus_printf(xbt, dev->nodename, "feature-barrier", "%d", state); if (err) dev_warn(&dev->dev, "writing feature-barrier (%d)", err); return err; } /* * Entry point to this code when a new device is created. Allocate the basic * structures, and watch the store waiting for the hotplug scripts to tell us * the device's physical major and minor numbers. Switch to InitWait. */ static int xen_blkbk_probe(struct xenbus_device *dev, const struct xenbus_device_id *id) { int err; struct backend_info *be = kzalloc(sizeof(struct backend_info), GFP_KERNEL); /* match the pr_debug in xen_blkbk_remove */ pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); if (!be) { xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure"); return -ENOMEM; } be->dev = dev; dev_set_drvdata(&dev->dev, be); be->blkif = xen_blkif_alloc(dev->otherend_id); if (IS_ERR(be->blkif)) { err = PTR_ERR(be->blkif); be->blkif = NULL; xenbus_dev_fatal(dev, err, "creating block interface"); goto fail; } err = xenbus_printf(XBT_NIL, dev->nodename, "feature-max-indirect-segments", "%u", MAX_INDIRECT_SEGMENTS); if (err) dev_warn(&dev->dev, "writing %s/feature-max-indirect-segments (%d)", dev->nodename, err); /* Multi-queue: advertise how many queues are supported by us.*/ err = xenbus_printf(XBT_NIL, dev->nodename, "multi-queue-max-queues", "%u", xenblk_max_queues); if (err) pr_warn("Error writing multi-queue-max-queues\n"); /* setup back pointer */ be->blkif->be = be; err = xenbus_watch_pathfmt(dev, &be->backend_watch, NULL, backend_changed, "%s/%s", dev->nodename, "physical-device"); if (err) goto fail; err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page-order", "%u", xen_blkif_max_ring_order); if (err) pr_warn("%s write out 'max-ring-page-order' failed\n", __func__); err = xenbus_switch_state(dev, XenbusStateInitWait); if (err) goto fail; return 0; fail: pr_warn("%s failed\n", __func__); xen_blkbk_remove(dev); return err; } /* * Callback received when the hotplug scripts have placed the physical-device * node. Read it and the mode node, and create a vbd. If the frontend is * ready, connect. */ static void backend_changed(struct xenbus_watch *watch, const char *path, const char *token) { int err; unsigned major; unsigned minor; struct backend_info *be = container_of(watch, struct backend_info, backend_watch); struct xenbus_device *dev = be->dev; int cdrom = 0; unsigned long handle; char *device_type; pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", &major, &minor); if (XENBUS_EXIST_ERR(err)) { /* * Since this watch will fire once immediately after it is * registered, we expect this. Ignore it, and wait for the * hotplug scripts. */ return; } if (err != 2) { xenbus_dev_fatal(dev, err, "reading physical-device"); return; } if (be->major | be->minor) { if (be->major != major || be->minor != minor) pr_warn("changing physical device (from %x:%x to %x:%x) not supported.\n", be->major, be->minor, major, minor); return; } be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); if (IS_ERR(be->mode)) { err = PTR_ERR(be->mode); be->mode = NULL; xenbus_dev_fatal(dev, err, "reading mode"); return; } device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); if (!IS_ERR(device_type)) { cdrom = strcmp(device_type, "cdrom") == 0; kfree(device_type); } /* Front end dir is a number, which is used as the handle. */ err = kstrtoul(strrchr(dev->otherend, '/') + 1, 0, &handle); if (err) { kfree(be->mode); be->mode = NULL; return; } be->major = major; be->minor = minor; err = xen_vbd_create(be->blkif, handle, major, minor, !strchr(be->mode, 'w'), cdrom); if (err) xenbus_dev_fatal(dev, err, "creating vbd structure"); else { err = xenvbd_sysfs_addif(dev); if (err) { xen_vbd_free(&be->blkif->vbd); xenbus_dev_fatal(dev, err, "creating sysfs entries"); } } if (err) { kfree(be->mode); be->mode = NULL; be->major = 0; be->minor = 0; } else { /* We're potentially connected now */ xen_update_blkif_status(be->blkif); } } /* * Callback received when the frontend's state changes. */ static void frontend_changed(struct xenbus_device *dev, enum xenbus_state frontend_state) { struct backend_info *be = dev_get_drvdata(&dev->dev); int err; pr_debug("%s %p %s\n", __func__, dev, xenbus_strstate(frontend_state)); switch (frontend_state) { case XenbusStateInitialising: if (dev->state == XenbusStateClosed) { pr_info("%s: prepare for reconnect\n", dev->nodename); xenbus_switch_state(dev, XenbusStateInitWait); } break; case XenbusStateInitialised: case XenbusStateConnected: /* * Ensure we connect even when two watches fire in * close succession and we miss the intermediate value * of frontend_state. */ if (dev->state == XenbusStateConnected) break; /* * Enforce precondition before potential leak point. * xen_blkif_disconnect() is idempotent. */ err = xen_blkif_disconnect(be->blkif); if (err) { xenbus_dev_fatal(dev, err, "pending I/O"); break; } err = connect_ring(be); if (err) { /* * Clean up so that memory resources can be used by * other devices. connect_ring reported already error. */ xen_blkif_disconnect(be->blkif); break; } xen_update_blkif_status(be->blkif); break; case XenbusStateClosing: xenbus_switch_state(dev, XenbusStateClosing); break; case XenbusStateClosed: xen_blkif_disconnect(be->blkif); xenbus_switch_state(dev, XenbusStateClosed); if (xenbus_dev_is_online(dev)) break; fallthrough; /* if not online */ case XenbusStateUnknown: /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ device_unregister(&dev->dev); break; default: xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", frontend_state); break; } } /* Once a memory pressure is detected, squeeze free page pools for a while. */ static unsigned int buffer_squeeze_duration_ms = 10; module_param_named(buffer_squeeze_duration_ms, buffer_squeeze_duration_ms, int, 0644); MODULE_PARM_DESC(buffer_squeeze_duration_ms, "Duration in ms to squeeze pages buffer when a memory pressure is detected"); /* * Callback received when the memory pressure is detected. */ static void reclaim_memory(struct xenbus_device *dev) { struct backend_info *be = dev_get_drvdata(&dev->dev); if (!be) return; be->blkif->buffer_squeeze_end = jiffies + msecs_to_jiffies(buffer_squeeze_duration_ms); } /* ** Connection ** */ /* * Write the physical details regarding the block device to the store, and * switch to Connected state. */ static void connect(struct backend_info *be) { struct xenbus_transaction xbt; int err; struct xenbus_device *dev = be->dev; pr_debug("%s %s\n", __func__, dev->otherend); /* Supply the information about the device the frontend needs */ again: err = xenbus_transaction_start(&xbt); if (err) { xenbus_dev_fatal(dev, err, "starting transaction"); return; } /* If we can't advertise it is OK. */ xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); xen_blkbk_discard(xbt, be); xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", be->blkif->vbd.feature_gnt_persistent_parm); if (err) { xenbus_dev_fatal(dev, err, "writing %s/feature-persistent", dev->nodename); goto abort; } err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", (unsigned long long)vbd_sz(&be->blkif->vbd)); if (err) { xenbus_dev_fatal(dev, err, "writing %s/sectors", dev->nodename); goto abort; } /* FIXME: use a typename instead */ err = xenbus_printf(xbt, dev->nodename, "info", "%u", be->blkif->vbd.type | (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); if (err) { xenbus_dev_fatal(dev, err, "writing %s/info", dev->nodename); goto abort; } err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", (unsigned long)bdev_logical_block_size( file_bdev(be->blkif->vbd.bdev_file))); if (err) { xenbus_dev_fatal(dev, err, "writing %s/sector-size", dev->nodename); goto abort; } err = xenbus_printf(xbt, dev->nodename, "physical-sector-size", "%u", bdev_physical_block_size( file_bdev(be->blkif->vbd.bdev_file))); if (err) xenbus_dev_error(dev, err, "writing %s/physical-sector-size", dev->nodename); err = xenbus_transaction_end(xbt, 0); if (err == -EAGAIN) goto again; if (err) xenbus_dev_fatal(dev, err, "ending transaction"); err = xenbus_switch_state(dev, XenbusStateConnected); if (err) xenbus_dev_fatal(dev, err, "%s: switching to Connected state", dev->nodename); return; abort: xenbus_transaction_end(xbt, 1); } /* * Each ring may have multi pages, depends on "ring-page-order". */ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir) { unsigned int ring_ref[XENBUS_MAX_RING_GRANTS]; struct pending_req *req, *n; int err, i, j; struct xen_blkif *blkif = ring->blkif; struct xenbus_device *dev = blkif->be->dev; unsigned int nr_grefs, evtchn; err = xenbus_scanf(XBT_NIL, dir, "event-channel", "%u", &evtchn); if (err != 1) { err = -EINVAL; xenbus_dev_fatal(dev, err, "reading %s/event-channel", dir); return err; } nr_grefs = blkif->nr_ring_pages; if (unlikely(!nr_grefs)) { WARN_ON(true); return -EINVAL; } for (i = 0; i < nr_grefs; i++) { char ring_ref_name[RINGREF_NAME_LEN]; if (blkif->multi_ref) snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); else { WARN_ON(i != 0); snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref"); } err = xenbus_scanf(XBT_NIL, dir, ring_ref_name, "%u", &ring_ref[i]); if (err != 1) { err = -EINVAL; xenbus_dev_fatal(dev, err, "reading %s/%s", dir, ring_ref_name); return err; } } err = -ENOMEM; for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) { req = kzalloc(sizeof(*req), GFP_KERNEL); if (!req) goto fail; list_add_tail(&req->free_list, &ring->pending_free); for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL); if (!req->segments[j]) goto fail; } for (j = 0; j < MAX_INDIRECT_PAGES; j++) { req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]), GFP_KERNEL); if (!req->indirect_pages[j]) goto fail; } } /* Map the shared frame, irq etc. */ err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn); if (err) { xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn); goto fail; } return 0; fail: list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { list_del(&req->free_list); for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { if (!req->segments[j]) break; kfree(req->segments[j]); } for (j = 0; j < MAX_INDIRECT_PAGES; j++) { if (!req->indirect_pages[j]) break; kfree(req->indirect_pages[j]); } kfree(req); } return err; } static int connect_ring(struct backend_info *be) { struct xenbus_device *dev = be->dev; struct xen_blkif *blkif = be->blkif; char protocol[64] = ""; int err, i; char *xspath; size_t xspathsize; const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */ unsigned int requested_num_queues = 0; unsigned int ring_page_order; pr_debug("%s %s\n", __func__, dev->otherend); blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT; err = xenbus_scanf(XBT_NIL, dev->otherend, "protocol", "%63s", protocol); if (err <= 0) strcpy(protocol, "unspecified, assuming default"); else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; else { xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); return -ENOSYS; } blkif->vbd.feature_gnt_persistent_parm = feature_persistent; blkif->vbd.feature_gnt_persistent = blkif->vbd.feature_gnt_persistent_parm && xenbus_read_unsigned(dev->otherend, "feature-persistent", 0); blkif->vbd.overflow_max_grants = 0; /* * Read the number of hardware queues from frontend. */ requested_num_queues = xenbus_read_unsigned(dev->otherend, "multi-queue-num-queues", 1); if (requested_num_queues > xenblk_max_queues || requested_num_queues == 0) { /* Buggy or malicious guest. */ xenbus_dev_fatal(dev, err, "guest requested %u queues, exceeding the maximum of %u.", requested_num_queues, xenblk_max_queues); return -ENOSYS; } blkif->nr_rings = requested_num_queues; if (xen_blkif_alloc_rings(blkif)) return -ENOMEM; pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename, blkif->nr_rings, blkif->blk_protocol, protocol, blkif->vbd.feature_gnt_persistent ? "persistent grants" : ""); err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u", &ring_page_order); if (err != 1) { blkif->nr_ring_pages = 1; blkif->multi_ref = false; } else if (ring_page_order <= xen_blkif_max_ring_order) { blkif->nr_ring_pages = 1 << ring_page_order; blkif->multi_ref = true; } else { err = -EINVAL; xenbus_dev_fatal(dev, err, "requested ring page order %d exceed max:%d", ring_page_order, xen_blkif_max_ring_order); return err; } if (blkif->nr_rings == 1) return read_per_ring_refs(&blkif->rings[0], dev->otherend); else { xspathsize = strlen(dev->otherend) + xenstore_path_ext_size; xspath = kmalloc(xspathsize, GFP_KERNEL); if (!xspath) { xenbus_dev_fatal(dev, -ENOMEM, "reading ring references"); return -ENOMEM; } for (i = 0; i < blkif->nr_rings; i++) { memset(xspath, 0, xspathsize); snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend, i); err = read_per_ring_refs(&blkif->rings[i], xspath); if (err) { kfree(xspath); return err; } } kfree(xspath); } return 0; } static const struct xenbus_device_id xen_blkbk_ids[] = { { "vbd" }, { "" } }; static struct xenbus_driver xen_blkbk_driver = { .ids = xen_blkbk_ids, .probe = xen_blkbk_probe, .remove = xen_blkbk_remove, .otherend_changed = frontend_changed, .allow_rebind = true, .reclaim_memory = reclaim_memory, }; int xen_blkif_xenbus_init(void) { return xenbus_register_backend(&xen_blkbk_driver); } void xen_blkif_xenbus_fini(void) { xenbus_unregister_driver(&xen_blkbk_driver); }
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