dm: allocate requests in target when stacking on blk-mq devices
For blk-mq request-based DM the responsibility of allocating a cloned request is transfered from DM core to the target type. Doing so enables the cloned request to be allocated from the appropriate blk-mq request_queue's pool (only the DM target, e.g. multipath, can know which block device to send a given cloned request to). Care was taken to preserve compatibility with old-style block request completion that requires request-based DM _not_ acquire the clone request's queue lock in the completion path. As such, there are now 2 different request-based DM target_type interfaces: 1) the original .map_rq() interface will continue to be used for non-blk-mq devices -- the preallocated clone request is passed in from DM core. 2) a new .clone_and_map_rq() and .release_clone_rq() will be used for blk-mq devices -- blk_get_request() and blk_put_request() are used respectively from these hooks. dm_table_set_type() was updated to detect if the request-based target is being stacked on blk-mq devices, if so DM_TYPE_MQ_REQUEST_BASED is set. DM core disallows switching the DM table's type after it is set. This means that there is no mixing of non-blk-mq and blk-mq devices within the same request-based DM table. [This patch was started by Keith and later heavily modified by Mike] Tested-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer
Родитель
466d89a6bc
Коммит
e5863d9ad7
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@ -11,6 +11,7 @@
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#include "dm-path-selector.h"
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#include "dm-uevent.h"
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#include <linux/blkdev.h>
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#include <linux/ctype.h>
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#include <linux/init.h>
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#include <linux/mempool.h>
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@ -378,12 +379,13 @@ static int __must_push_back(struct multipath *m)
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/*
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* Map cloned requests
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*/
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static int multipath_map(struct dm_target *ti, struct request *clone,
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union map_info *map_context)
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static int __multipath_map(struct dm_target *ti, struct request *clone,
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union map_info *map_context,
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struct request *rq, struct request **__clone)
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{
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struct multipath *m = (struct multipath *) ti->private;
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int r = DM_MAPIO_REQUEUE;
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size_t nr_bytes = blk_rq_bytes(clone);
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size_t nr_bytes = clone ? blk_rq_bytes(clone) : blk_rq_bytes(rq);
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struct pgpath *pgpath;
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struct block_device *bdev;
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struct dm_mpath_io *mpio;
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@ -416,11 +418,24 @@ static int multipath_map(struct dm_target *ti, struct request *clone,
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bdev = pgpath->path.dev->bdev;
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spin_unlock_irq(&m->lock);
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if (clone) {
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/* Old request-based interface: allocated clone is passed in */
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clone->q = bdev_get_queue(bdev);
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clone->rq_disk = bdev->bd_disk;
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clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
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spin_unlock_irq(&m->lock);
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} else {
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/* blk-mq request-based interface */
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*__clone = blk_get_request(bdev_get_queue(bdev),
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rq_data_dir(rq), GFP_KERNEL);
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if (IS_ERR(*__clone))
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/* ENOMEM, requeue */
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return r;
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(*__clone)->bio = (*__clone)->biotail = NULL;
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(*__clone)->rq_disk = bdev->bd_disk;
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(*__clone)->cmd_flags |= REQ_FAILFAST_TRANSPORT;
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}
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if (pgpath->pg->ps.type->start_io)
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pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
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@ -434,6 +449,24 @@ out_unlock:
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return r;
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}
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static int multipath_map(struct dm_target *ti, struct request *clone,
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union map_info *map_context)
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{
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return __multipath_map(ti, clone, map_context, NULL, NULL);
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}
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static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
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union map_info *map_context,
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struct request **clone)
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{
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return __multipath_map(ti, NULL, map_context, rq, clone);
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}
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static void multipath_release_clone(struct request *clone)
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{
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blk_put_request(clone);
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}
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/*
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* If we run out of usable paths, should we queue I/O or error it?
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*/
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@ -1670,11 +1703,13 @@ out:
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*---------------------------------------------------------------*/
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static struct target_type multipath_target = {
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.name = "multipath",
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.version = {1, 7, 0},
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.version = {1, 8, 0},
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.module = THIS_MODULE,
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.ctr = multipath_ctr,
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.dtr = multipath_dtr,
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.map_rq = multipath_map,
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.clone_and_map_rq = multipath_clone_and_map,
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.release_clone_rq = multipath_release_clone,
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.rq_end_io = multipath_end_io,
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.presuspend = multipath_presuspend,
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.postsuspend = multipath_postsuspend,
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@ -827,6 +827,7 @@ static int dm_table_set_type(struct dm_table *t)
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{
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unsigned i;
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unsigned bio_based = 0, request_based = 0, hybrid = 0;
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bool use_blk_mq = false;
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struct dm_target *tgt;
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struct dm_dev_internal *dd;
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struct list_head *devices;
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@ -872,11 +873,26 @@ static int dm_table_set_type(struct dm_table *t)
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/* Non-request-stackable devices can't be used for request-based dm */
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devices = dm_table_get_devices(t);
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list_for_each_entry(dd, devices, list) {
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if (!blk_queue_stackable(bdev_get_queue(dd->dm_dev->bdev))) {
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DMWARN("table load rejected: including"
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struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
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if (!blk_queue_stackable(q)) {
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DMERR("table load rejected: including"
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" non-request-stackable devices");
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return -EINVAL;
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}
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if (q->mq_ops)
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use_blk_mq = true;
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}
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if (use_blk_mq) {
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/* verify _all_ devices in the table are blk-mq devices */
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list_for_each_entry(dd, devices, list)
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if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
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DMERR("table load rejected: not all devices"
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" are blk-mq request-stackable");
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return -EINVAL;
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}
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}
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/*
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@ -890,7 +906,7 @@ static int dm_table_set_type(struct dm_table *t)
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return -EINVAL;
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}
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t->type = DM_TYPE_REQUEST_BASED;
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t->type = !use_blk_mq ? DM_TYPE_REQUEST_BASED : DM_TYPE_MQ_REQUEST_BASED;
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return 0;
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}
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@ -907,7 +923,15 @@ struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
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bool dm_table_request_based(struct dm_table *t)
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{
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return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED;
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unsigned table_type = dm_table_get_type(t);
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return (table_type == DM_TYPE_REQUEST_BASED ||
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table_type == DM_TYPE_MQ_REQUEST_BASED);
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}
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bool dm_table_mq_request_based(struct dm_table *t)
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{
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return dm_table_get_type(t) == DM_TYPE_MQ_REQUEST_BASED;
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}
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static int dm_table_alloc_md_mempools(struct dm_table *t)
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@ -137,13 +137,26 @@ static int io_err_map_rq(struct dm_target *ti, struct request *clone,
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return -EIO;
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}
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static int io_err_clone_and_map_rq(struct dm_target *ti, struct request *rq,
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union map_info *map_context,
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struct request **clone)
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{
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return -EIO;
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}
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static void io_err_release_clone_rq(struct request *clone)
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{
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}
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static struct target_type error_target = {
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.name = "error",
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.version = {1, 2, 0},
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.version = {1, 3, 0},
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.ctr = io_err_ctr,
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.dtr = io_err_dtr,
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.map = io_err_map,
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.map_rq = io_err_map_rq,
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.clone_and_map_rq = io_err_clone_and_map_rq,
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.release_clone_rq = io_err_release_clone_rq,
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};
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int __init dm_target_init(void)
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@ -1044,6 +1044,9 @@ static void free_rq_clone(struct request *clone)
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struct dm_rq_target_io *tio = clone->end_io_data;
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blk_rq_unprep_clone(clone);
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if (clone->q && clone->q->mq_ops)
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tio->ti->type->release_clone_rq(clone);
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else
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free_clone_request(tio->md, clone);
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free_rq_tio(tio);
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}
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@ -1086,6 +1089,7 @@ static void dm_unprep_request(struct request *rq)
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rq->special = NULL;
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rq->cmd_flags &= ~REQ_DONTPREP;
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if (clone)
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free_rq_clone(clone);
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}
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@ -1185,6 +1189,13 @@ static void dm_softirq_done(struct request *rq)
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struct dm_rq_target_io *tio = rq->special;
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struct request *clone = tio->clone;
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if (!clone) {
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blk_end_request_all(rq, tio->error);
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rq_completed(tio->md, rq_data_dir(rq), false);
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free_rq_tio(tio);
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return;
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}
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if (rq->cmd_flags & REQ_FAILED)
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mapped = false;
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@ -1207,7 +1218,7 @@ static void dm_complete_request(struct request *rq, int error)
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* Complete the not-mapped clone and the original request with the error status
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* through softirq context.
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* Target's rq_end_io() function isn't called.
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* This may be used when the target's map_rq() function fails.
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* This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
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*/
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static void dm_kill_unmapped_request(struct request *rq, int error)
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{
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@ -1222,13 +1233,15 @@ static void end_clone_request(struct request *clone, int error)
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{
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struct dm_rq_target_io *tio = clone->end_io_data;
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if (!clone->q->mq_ops) {
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/*
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* For just cleaning up the information of the queue in which
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* the clone was dispatched.
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* The clone is *NOT* freed actually here because it is alloced from
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* dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
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* The clone is *NOT* freed actually here because it is alloced
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* from dm own mempool (REQ_ALLOCED isn't set).
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*/
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__blk_put_request(clone->q, clone);
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}
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/*
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* Actual request completion is done in a softirq context which doesn't
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@ -1789,6 +1802,8 @@ static struct dm_rq_target_io *prep_tio(struct request *rq,
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struct mapped_device *md, gfp_t gfp_mask)
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{
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struct dm_rq_target_io *tio;
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int srcu_idx;
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struct dm_table *table;
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tio = alloc_rq_tio(md, gfp_mask);
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if (!tio)
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@ -1802,10 +1817,15 @@ static struct dm_rq_target_io *prep_tio(struct request *rq,
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memset(&tio->info, 0, sizeof(tio->info));
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init_kthread_work(&tio->work, map_tio_request);
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table = dm_get_live_table(md, &srcu_idx);
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if (!dm_table_mq_request_based(table)) {
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if (!clone_rq(rq, md, tio, gfp_mask)) {
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dm_put_live_table(md, srcu_idx);
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free_rq_tio(tio);
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return NULL;
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}
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}
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dm_put_live_table(md, srcu_idx);
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return tio;
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}
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@ -1835,17 +1855,36 @@ static int dm_prep_fn(struct request_queue *q, struct request *rq)
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/*
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* Returns:
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* 0 : the request has been processed (not requeued)
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* !0 : the request has been requeued
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* 0 : the request has been processed
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* DM_MAPIO_REQUEUE : the original request needs to be requeued
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* < 0 : the request was completed due to failure
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*/
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static int map_request(struct dm_target *ti, struct request *rq,
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struct mapped_device *md)
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{
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int r, requeued = 0;
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int r;
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struct dm_rq_target_io *tio = rq->special;
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struct request *clone = tio->clone;
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struct request *clone = NULL;
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if (tio->clone) {
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clone = tio->clone;
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r = ti->type->map_rq(ti, clone, &tio->info);
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} else {
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r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
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if (r < 0) {
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/* The target wants to complete the I/O */
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dm_kill_unmapped_request(rq, r);
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return r;
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}
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if (IS_ERR(clone))
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return DM_MAPIO_REQUEUE;
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if (setup_clone(clone, rq, tio, GFP_KERNEL)) {
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/* -ENOMEM */
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ti->type->release_clone_rq(clone);
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return DM_MAPIO_REQUEUE;
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}
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}
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switch (r) {
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case DM_MAPIO_SUBMITTED:
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/* The target has taken the I/O to submit by itself later */
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@ -1859,7 +1898,6 @@ static int map_request(struct dm_target *ti, struct request *rq,
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case DM_MAPIO_REQUEUE:
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/* The target wants to requeue the I/O */
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dm_requeue_unmapped_request(clone);
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requeued = 1;
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break;
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default:
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if (r > 0) {
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@ -1869,17 +1907,20 @@ static int map_request(struct dm_target *ti, struct request *rq,
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/* The target wants to complete the I/O */
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dm_kill_unmapped_request(rq, r);
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break;
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return r;
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}
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return requeued;
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return 0;
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}
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static void map_tio_request(struct kthread_work *work)
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{
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struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work);
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struct request *rq = tio->orig;
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struct mapped_device *md = tio->md;
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map_request(tio->ti, tio->orig, tio->md);
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if (map_request(tio->ti, rq, md) == DM_MAPIO_REQUEUE)
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dm_requeue_unmapped_original_request(md, rq);
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}
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static void dm_start_request(struct mapped_device *md, struct request *orig)
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@ -2459,6 +2500,14 @@ unsigned dm_get_md_type(struct mapped_device *md)
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return md->type;
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}
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static bool dm_md_type_request_based(struct mapped_device *md)
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{
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unsigned table_type = dm_get_md_type(md);
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return (table_type == DM_TYPE_REQUEST_BASED ||
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table_type == DM_TYPE_MQ_REQUEST_BASED);
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}
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struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
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{
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return md->immutable_target_type;
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@ -2511,8 +2560,7 @@ static int dm_init_request_based_queue(struct mapped_device *md)
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*/
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int dm_setup_md_queue(struct mapped_device *md)
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{
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if ((dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) &&
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!dm_init_request_based_queue(md)) {
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if (dm_md_type_request_based(md) && !dm_init_request_based_queue(md)) {
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DMWARN("Cannot initialize queue for request-based mapped device");
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return -EINVAL;
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}
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@ -3184,27 +3232,35 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, u
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{
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struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
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struct kmem_cache *cachep;
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unsigned int pool_size;
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unsigned int pool_size = 0;
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unsigned int front_pad;
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if (!pools)
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return NULL;
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if (type == DM_TYPE_BIO_BASED) {
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switch (type) {
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case DM_TYPE_BIO_BASED:
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cachep = _io_cache;
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pool_size = dm_get_reserved_bio_based_ios();
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front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
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} else if (type == DM_TYPE_REQUEST_BASED) {
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cachep = _rq_tio_cache;
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break;
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case DM_TYPE_REQUEST_BASED:
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pool_size = dm_get_reserved_rq_based_ios();
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pools->rq_pool = mempool_create_slab_pool(pool_size, _rq_cache);
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if (!pools->rq_pool)
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goto out;
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/* fall through to setup remaining rq-based pools */
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case DM_TYPE_MQ_REQUEST_BASED:
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cachep = _rq_tio_cache;
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if (!pool_size)
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pool_size = dm_get_reserved_rq_based_ios();
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front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
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/* per_bio_data_size is not used. See __bind_mempools(). */
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WARN_ON(per_bio_data_size != 0);
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} else
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break;
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default:
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goto out;
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}
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|
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pools->io_pool = mempool_create_slab_pool(pool_size, cachep);
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if (!pools->io_pool)
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|
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@ -37,6 +37,7 @@
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#define DM_TYPE_NONE 0
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#define DM_TYPE_BIO_BASED 1
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#define DM_TYPE_REQUEST_BASED 2
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#define DM_TYPE_MQ_REQUEST_BASED 3
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/*
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* List of devices that a metadevice uses and should open/close.
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@ -73,6 +74,7 @@ int dm_table_any_busy_target(struct dm_table *t);
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unsigned dm_table_get_type(struct dm_table *t);
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struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
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bool dm_table_request_based(struct dm_table *t);
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bool dm_table_mq_request_based(struct dm_table *t);
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void dm_table_free_md_mempools(struct dm_table *t);
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struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
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|
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@ -48,6 +48,11 @@ typedef void (*dm_dtr_fn) (struct dm_target *ti);
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typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
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typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
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union map_info *map_context);
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typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
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struct request *rq,
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union map_info *map_context,
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struct request **clone);
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typedef void (*dm_release_clone_request_fn) (struct request *clone);
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/*
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* Returns:
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|
@ -143,6 +148,8 @@ struct target_type {
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dm_dtr_fn dtr;
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dm_map_fn map;
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dm_map_request_fn map_rq;
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dm_clone_and_map_request_fn clone_and_map_rq;
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dm_release_clone_request_fn release_clone_rq;
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dm_endio_fn end_io;
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dm_request_endio_fn rq_end_io;
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dm_presuspend_fn presuspend;
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|
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@ -267,9 +267,9 @@ enum {
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#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
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#define DM_VERSION_MAJOR 4
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#define DM_VERSION_MINOR 29
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#define DM_VERSION_MINOR 30
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#define DM_VERSION_PATCHLEVEL 0
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#define DM_VERSION_EXTRA "-ioctl (2014-10-28)"
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#define DM_VERSION_EXTRA "-ioctl (2014-12-22)"
|
||||
|
||||
/* Status bits */
|
||||
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
|
||||
|
|
|
|||
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