cregit-Linux how code gets into the kernel

Release 4.7 drivers/block/osdblk.c

Directory: drivers/block
/*
   osdblk.c -- Export a single SCSI OSD object as a Linux block device


   Copyright 2009 Red Hat, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.


   Instructions for use
   --------------------

   1) Map a Linux block device to an existing OSD object.

      In this example, we will use partition id 1234, object id 5678,
      OSD device /dev/osd1.

      $ echo "1234 5678 /dev/osd1" > /sys/class/osdblk/add


   2) List all active blkdev<->object mappings.

      In this example, we have performed step #1 twice, creating two blkdevs,
      mapped to two separate OSD objects.

      $ cat /sys/class/osdblk/list
      0 174 1234 5678 /dev/osd1
      1 179 1994 897123 /dev/osd0

      The columns, in order, are:
      - blkdev unique id
      - blkdev assigned major
      - OSD object partition id
      - OSD object id
      - OSD device


   3) Remove an active blkdev<->object mapping.

      In this example, we remove the mapping with blkdev unique id 1.

      $ echo 1 > /sys/class/osdblk/remove


   NOTE:  The actual creation and deletion of OSD objects is outside the scope
   of this driver.

 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <scsi/osd_initiator.h>
#include <scsi/osd_attributes.h>
#include <scsi/osd_sec.h>
#include <scsi/scsi_device.h>


#define DRV_NAME "osdblk"

#define PFX DRV_NAME ": "

/* #define _OSDBLK_DEBUG */
#ifdef _OSDBLK_DEBUG

#define OSDBLK_DEBUG(fmt, a...) \
	printk(KERN_NOTICE "osdblk @%s:%d: " fmt, __func__, __LINE__, ##a)
#else

#define OSDBLK_DEBUG(fmt, a...) \
	do { if (0) printk(fmt, ##a); } while (0)
#endif

MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>");
MODULE_DESCRIPTION("block device inside an OSD object osdblk.ko");
MODULE_LICENSE("GPL");

struct osdblk_device;

enum {
	
OSDBLK_MINORS_PER_MAJOR	= 256,		/* max minors per blkdev */
	
OSDBLK_MAX_REQ		= 32,		/* max parallel requests */
	
OSDBLK_OP_TIMEOUT	= 4 * 60,	/* sync OSD req timeout */
};


struct osdblk_request {
	
struct request		*rq;		/* blk layer request */
	
struct bio		*bio;		/* cloned bio */
	
struct osdblk_device	*osdev;		/* associated blkdev */
};


struct osdblk_device {
	
int			id;		/* blkdev unique id */

	
int			major;		/* blkdev assigned major */
	
struct gendisk		*disk;		/* blkdev's gendisk and rq */
	
struct request_queue	*q;

	
struct osd_dev		*osd;		/* associated OSD */

	
char			name[32];	/* blkdev name, e.g. osdblk34 */

	
spinlock_t		lock;		/* queue lock */

	
struct osd_obj_id	obj;		/* OSD partition, obj id */
	
uint8_t			obj_cred[OSD_CAP_LEN]; /* OSD cred */

	
struct osdblk_request	req[OSDBLK_MAX_REQ]; /* request table */

	
struct list_head	node;

	
char			osd_path[0];	/* OSD device path */
};


static struct class *class_osdblk;		
/* /sys/class/osdblk */
static DEFINE_MUTEX(ctl_mutex);	/* Serialize open/close/setup/teardown */
static LIST_HEAD(osdblkdev_list);


static const struct block_device_operations osdblk_bd_ops = {
	.owner		= THIS_MODULE,
};


static const struct osd_attr g_attr_logical_length = ATTR_DEF(
	OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);


static void osdblk_make_credential(u8 cred_a[OSD_CAP_LEN], const struct osd_obj_id *obj) { osd_sec_init_nosec_doall_caps(cred_a, obj, false, true); }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik29100.00%1100.00%
Total29100.00%1100.00%

/* copied from exofs; move to libosd? */ /* * Perform a synchronous OSD operation. copied from exofs; move to libosd? */
static int osd_sync_op(struct osd_request *or, int timeout, uint8_t *credential) { int ret; or->timeout = timeout; ret = osd_finalize_request(or, 0, credential, NULL); if (ret) return ret; ret = osd_execute_request(or); /* osd_req_decode_sense(or, ret); */ return ret; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik58100.00%1100.00%
Total58100.00%1100.00%

/* * Perform an asynchronous OSD operation. copied from exofs; move to libosd? */
static int osd_async_op(struct osd_request *or, osd_req_done_fn *async_done, void *caller_context, u8 *cred) { int ret; ret = osd_finalize_request(or, 0, cred, NULL); if (ret) return ret; ret = osd_execute_request_async(or, async_done, caller_context); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik60100.00%1100.00%
Total60100.00%1100.00%

/* copied from exofs; move to libosd? */
static int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr) { struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */ void *iter = NULL; int nelem; do { nelem = 1; osd_req_decode_get_attr_list(or, &cur_attr, &nelem, &iter); if ((cur_attr.attr_page == attr->attr_page) && (cur_attr.attr_id == attr->attr_id)) { attr->len = cur_attr.len; attr->val_ptr = cur_attr.val_ptr; return 0; } } while (iter); return -EIO; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik110100.00%1100.00%
Total110100.00%1100.00%


static int osdblk_get_obj_size(struct osdblk_device *osdev, u64 *size_out) { struct osd_request *or; struct osd_attr attr; int ret; /* start request */ or = osd_start_request(osdev->osd, GFP_KERNEL); if (!or) return -ENOMEM; /* create a get-attributes(length) request */ osd_req_get_attributes(or, &osdev->obj); osd_req_add_get_attr_list(or, &g_attr_logical_length, 1); /* execute op synchronously */ ret = osd_sync_op(or, OSDBLK_OP_TIMEOUT, osdev->obj_cred); if (ret) goto out; /* extract length from returned attribute info */ attr = g_attr_logical_length; ret = extract_attr_from_req(or, &attr); if (ret) goto out; *size_out = get_unaligned_be64(attr.val_ptr); out: osd_end_request(or); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik132100.00%1100.00%
Total132100.00%1100.00%


static void osdblk_osd_complete(struct osd_request *or, void *private) { struct osdblk_request *orq = private; struct osd_sense_info osi; int ret = osd_req_decode_sense(or, &osi); if (ret) { ret = -EIO; OSDBLK_DEBUG("osdblk_osd_complete with err=%d\n", ret); } /* complete OSD request */ osd_end_request(or); /* complete request passed to osdblk by block layer */ __blk_end_request_all(orq->rq, ret); }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik71100.00%1100.00%
Total71100.00%1100.00%


static void bio_chain_put(struct bio *chain) { struct bio *tmp; while (chain) { tmp = chain; chain = chain->bi_next; bio_put(tmp); } }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik37100.00%1100.00%
Total37100.00%1100.00%


static struct bio *bio_chain_clone(struct bio *old_chain, gfp_t gfpmask) { struct bio *tmp, *new_chain = NULL, *tail = NULL; while (old_chain) { tmp = bio_clone_kmalloc(old_chain, gfpmask); if (!tmp) goto err_out; tmp->bi_bdev = NULL; gfpmask &= ~__GFP_DIRECT_RECLAIM; tmp->bi_next = NULL; if (!new_chain) new_chain = tail = tmp; else { tail->bi_next = tmp; tail = tmp; } old_chain = old_chain->bi_next; } return new_chain; err_out: OSDBLK_DEBUG("bio_chain_clone with err\n"); bio_chain_put(new_chain); return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik11596.64%133.33%
kent overstreetkent overstreet32.52%133.33%
mel gormanmel gorman10.84%133.33%
Total119100.00%3100.00%


static void osdblk_rq_fn(struct request_queue *q) { struct osdblk_device *osdev = q->queuedata; while (1) { struct request *rq; struct osdblk_request *orq; struct osd_request *or; struct bio *bio; bool do_write, do_flush; /* peek at request from block layer */ rq = blk_fetch_request(q); if (!rq) break; /* filter out block requests we don't understand */ if (rq->cmd_type != REQ_TYPE_FS) { blk_end_request_all(rq, 0); continue; } /* deduce our operation (read, write, flush) */ /* I wish the block layer simplified cmd_type/cmd_flags/cmd[] * into a clearly defined set of RPC commands: * read, write, flush, scsi command, power mgmt req, * driver-specific, etc. */ do_flush = rq->cmd_flags & REQ_FLUSH; do_write = (rq_data_dir(rq) == WRITE); if (!do_flush) { /* osd_flush does not use a bio */ /* a bio clone to be passed down to OSD request */ bio = bio_chain_clone(rq->bio, GFP_ATOMIC); if (!bio) break; } else bio = NULL; /* alloc internal OSD request, for OSD command execution */ or = osd_start_request(osdev->osd, GFP_ATOMIC); if (!or) { bio_chain_put(bio); OSDBLK_DEBUG("osd_start_request with err\n"); break; } orq = &osdev->req[rq->tag]; orq->rq = rq; orq->bio = bio; orq->osdev = osdev; /* init OSD command: flush, write or read */ if (do_flush) osd_req_flush_object(or, &osdev->obj, OSD_CDB_FLUSH_ALL, 0, 0); else if (do_write) osd_req_write(or, &osdev->obj, blk_rq_pos(rq) * 512ULL, bio, blk_rq_bytes(rq)); else osd_req_read(or, &osdev->obj, blk_rq_pos(rq) * 512ULL, bio, blk_rq_bytes(rq)); OSDBLK_DEBUG("%s 0x%x bytes at 0x%llx\n", do_flush ? "flush" : do_write ? "write" : "read", blk_rq_bytes(rq), blk_rq_pos(rq) * 512ULL); /* begin OSD command execution */ if (osd_async_op(or, osdblk_osd_complete, orq, osdev->obj_cred)) { osd_end_request(or); blk_requeue_request(q, rq); bio_chain_put(bio); OSDBLK_DEBUG("osd_execute_request_async with err\n"); break; } /* remove the special 'flush' marker, now that the command * is executing */ rq->special = NULL; } }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik33997.98%133.33%
christoph hellwigchristoph hellwig41.16%133.33%
fujita tomonorifujita tomonori30.87%133.33%
Total346100.00%3100.00%


static void osdblk_free_disk(struct osdblk_device *osdev) { struct gendisk *disk = osdev->disk; if (!disk) return; if (disk->flags & GENHD_FL_UP) del_gendisk(disk); if (disk->queue) blk_cleanup_queue(disk->queue); put_disk(disk); }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik57100.00%1100.00%
Total57100.00%1100.00%


static int osdblk_init_disk(struct osdblk_device *osdev) { struct gendisk *disk; struct request_queue *q; int rc; u64 obj_size = 0; /* contact OSD, request size info about the object being mapped */ rc = osdblk_get_obj_size(osdev, &obj_size); if (rc) return rc; /* create gendisk info */ disk = alloc_disk(OSDBLK_MINORS_PER_MAJOR); if (!disk) return -ENOMEM; sprintf(disk->disk_name, DRV_NAME "%d", osdev->id); disk->major = osdev->major; disk->first_minor = 0; disk->fops = &osdblk_bd_ops; disk->private_data = osdev; /* init rq */ q = blk_init_queue(osdblk_rq_fn, &osdev->lock); if (!q) { put_disk(disk); return -ENOMEM; } /* switch queue to TCQ mode; allocate tag map */ rc = blk_queue_init_tags(q, OSDBLK_MAX_REQ, NULL, BLK_TAG_ALLOC_FIFO); if (rc) { blk_cleanup_queue(q); put_disk(disk); return rc; } /* Set our limits to the lower device limits, because osdblk cannot * sleep when allocating a lower-request and therefore cannot be * bouncing. */ blk_queue_stack_limits(q, osd_request_queue(osdev->osd)); blk_queue_prep_rq(q, blk_queue_start_tag); blk_queue_write_cache(q, true, false); disk->queue = q; q->queuedata = osdev; osdev->disk = disk; osdev->q = q; /* finally, announce the disk to the world */ set_capacity(disk, obj_size / 512ULL); add_disk(disk); printk(KERN_INFO "%s: Added of size 0x%llx\n", disk->disk_name, (unsigned long long)obj_size); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik23692.55%125.00%
boaz harroshboaz harrosh135.10%125.00%
jens axboejens axboe41.57%125.00%
shaohua lishaohua li20.78%125.00%
Total255100.00%4100.00%

/******************************************************************** * /sys/class/osdblk/ * add map OSD object to blkdev * remove unmap OSD object * list show mappings *******************************************************************/
static void class_osdblk_release(struct class *cls) { kfree(cls); }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik16100.00%1100.00%
Total16100.00%1100.00%


static ssize_t class_osdblk_list(struct class *c, struct class_attribute *attr, char *data) { int n = 0; struct list_head *tmp; mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); list_for_each(tmp, &osdblkdev_list) { struct osdblk_device *osdev; osdev = list_entry(tmp, struct osdblk_device, node); n += sprintf(data+n, "%d %d %llu %llu %s\n", osdev->id, osdev->major, osdev->obj.partition, osdev->obj.id, osdev->osd_path); } mutex_unlock(&ctl_mutex); return n; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik10295.33%150.00%
andi kleenandi kleen54.67%150.00%
Total107100.00%2100.00%


static ssize_t class_osdblk_add(struct class *c, struct class_attribute *attr, const char *buf, size_t count) { struct osdblk_device *osdev; ssize_t rc; int irc, new_id = 0; struct list_head *tmp; if (!try_module_get(THIS_MODULE)) return -ENODEV; /* new osdblk_device object */ osdev = kzalloc(sizeof(*osdev) + strlen(buf) + 1, GFP_KERNEL); if (!osdev) { rc = -ENOMEM; goto err_out_mod; } /* static osdblk_device initialization */ spin_lock_init(&osdev->lock); INIT_LIST_HEAD(&osdev->node); /* generate unique id: find highest unique id, add one */ mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); list_for_each(tmp, &osdblkdev_list) { struct osdblk_device *osdev; osdev = list_entry(tmp, struct osdblk_device, node); if (osdev->id > new_id) new_id = osdev->id + 1; } osdev->id = new_id; /* add to global list */ list_add_tail(&osdev->node, &osdblkdev_list); mutex_unlock(&ctl_mutex); /* parse add command */ if (sscanf(buf, "%llu %llu %s", &osdev->obj.partition, &osdev->obj.id, osdev->osd_path) != 3) { rc = -EINVAL; goto err_out_slot; } /* initialize rest of new object */ sprintf(osdev->name, DRV_NAME "%d", osdev->id); /* contact requested OSD */ osdev->osd = osduld_path_lookup(osdev->osd_path); if (IS_ERR(osdev->osd)) { rc = PTR_ERR(osdev->osd); goto err_out_slot; } /* build OSD credential */ osdblk_make_credential(osdev->obj_cred, &osdev->obj); /* register our block device */ irc = register_blkdev(0, osdev->name); if (irc < 0) { rc = irc; goto err_out_osd; } osdev->major = irc; /* set up and announce blkdev mapping */ rc = osdblk_init_disk(osdev); if (rc) goto err_out_blkdev; return count; err_out_blkdev: unregister_blkdev(osdev->major, osdev->name); err_out_osd: osduld_put_device(osdev->osd); err_out_slot: mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); list_del_init(&osdev->node); mutex_unlock(&ctl_mutex); kfree(osdev); err_out_mod: OSDBLK_DEBUG("Error adding device %s\n", buf); module_put(THIS_MODULE); return rc; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik40098.77%150.00%
andi kleenandi kleen51.23%150.00%
Total405100.00%2100.00%


static ssize_t class_osdblk_remove(struct class *c, struct class_attribute *attr, const char *buf, size_t count) { struct osdblk_device *osdev = NULL; int target_id, rc; unsigned long ul; struct list_head *tmp; rc = kstrtoul(buf, 10, &ul); if (rc) return rc; /* convert to int; abort if we lost anything in the conversion */ target_id = (int) ul; if (target_id != ul) return -EINVAL; /* remove object from list immediately */ mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); list_for_each(tmp, &osdblkdev_list) { osdev = list_entry(tmp, struct osdblk_device, node); if (osdev->id == target_id) { list_del_init(&osdev->node); break; } osdev = NULL; } mutex_unlock(&ctl_mutex); if (!osdev) return -ENOENT; /* clean up and free blkdev and associated OSD connection */ osdblk_free_disk(osdev); unregister_blkdev(osdev->major, osdev->name); osduld_put_device(osdev->osd); kfree(osdev); /* release module ref */ module_put(THIS_MODULE); return count; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik18196.79%133.33%
andi kleenandi kleen52.67%133.33%
jingoo hanjingoo han10.53%133.33%
Total187100.00%3100.00%

static struct class_attribute class_osdblk_attrs[] = { __ATTR(add, 0200, NULL, class_osdblk_add), __ATTR(remove, 0200, NULL, class_osdblk_remove), __ATTR(list, 0444, class_osdblk_list, NULL), __ATTR_NULL };
static int osdblk_sysfs_init(void) { int ret = 0; /* * create control files in sysfs * /sys/class/osdblk/... */ class_osdblk = kzalloc(sizeof(*class_osdblk), GFP_KERNEL); if (!class_osdblk) return -ENOMEM; class_osdblk->name = DRV_NAME; class_osdblk->owner = THIS_MODULE; class_osdblk->class_release = class_osdblk_release; class_osdblk->class_attrs = class_osdblk_attrs; ret = class_register(class_osdblk); if (ret) { kfree(class_osdblk); class_osdblk = NULL; printk(PFX "failed to create class osdblk\n"); return ret; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik94100.00%1100.00%
Total94100.00%1100.00%


static void osdblk_sysfs_cleanup(void) { if (class_osdblk) class_destroy(class_osdblk); class_osdblk = NULL; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik21100.00%1100.00%
Total21100.00%1100.00%


static int __init osdblk_init(void) { int rc; rc = osdblk_sysfs_init(); if (rc) return rc; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik27100.00%1100.00%
Total27100.00%1100.00%


static void __exit osdblk_exit(void) { osdblk_sysfs_cleanup(); }

Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik12100.00%1100.00%
Total12100.00%1100.00%

module_init(osdblk_init); module_exit(osdblk_exit);

Overall Contributors

PersonTokensPropCommitsCommitProp
jeff garzikjeff garzik239697.84%18.33%
boaz harroshboaz harrosh160.65%18.33%
andi kleenandi kleen150.61%18.33%
jens axboejens axboe40.16%18.33%
christoph hellwigchristoph hellwig40.16%18.33%
fujita tomonorifujita tomonori30.12%18.33%
kent overstreetkent overstreet30.12%18.33%
tejun heotejun heo30.12%18.33%
shaohua lishaohua li20.08%18.33%
alexey dobriyanalexey dobriyan10.04%18.33%
mel gormanmel gorman10.04%18.33%
jingoo hanjingoo han10.04%18.33%
Total2449100.00%12100.00%
Directory: drivers/block
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
{% endraw %}