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path: root/drivers/md
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2016-03-14md/raid1: remove unnecessary BUG_ONGuoqing Jiang
Since bitmap_start_sync will not return until sync_blocks is not less than PAGE_SIZE>>9, so the BUG_ON is not needed anymore. Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-03-14md: multipath: don't hardcopy bio in .make_request pathMing Lei
Inside multipath_make_request(), multipath maps the incoming bio into low level device's bio, but it is totally wrong to copy the bio into mapped bio via '*mapped_bio = *bio'. For example, .__bi_remaining is kept in the copy, especially if the incoming bio is chained to via bio splitting, so .bi_end_io can't be called for the mapped bio at all in the completing path in this kind of situation. This patch fixes the issue by using clone style. Cc: stable@vger.kernel.org (v3.14+) Reported-and-tested-by: Andrea Righi <righi.andrea@gmail.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-03-11dm thin: consistently return -ENOSPC if pool has run out of data spaceMike Snitzer
Commit 0a927c2f02 ("dm thin: return -ENOSPC when erroring retry list due to out of data space") was a step in the right direction but didn't go far enough. Add a new 'out_of_data_space' flag to 'struct pool' and set it if/when the pool runs of of data space. This fixes cell_error() and error_retry_list() to not blindly return -EIO. We cannot rely on the 'error_if_no_space' feature flag since it is transient (in that it can be reset once space is added, plus it only controls whether errors are issued, it doesn't reflect whether the pool is actually out of space). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm cache: bump the target versionMike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm cache: make sure every metadata function checks fail_ioJoe Thornber
Otherwise operations may be attempted that will only ever go on to crash (since the metadata device is either missing or unreliable if 'fail_io' is set). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2016-03-10dm: add missing newline between DM_DEBUG_BLOCK_STACK_TRACING and DM_BUFIOMike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm cache policy smq: clarify that mq registration failure was for 'mq'Mike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm: return error if bio_integrity_clone() fails in clone_bio()Mike Snitzer
clone_bio() now checks if bio_integrity_clone() returned an error rather than just drop it on the floor. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm thin metadata: don't issue prefetches if a transaction abort has failedJoe Thornber
If a transaction abort has failed then we can no longer use the metadata device. Typically this happens if the superblock is unreadable. This fix addresses a crash seen during metadata device failure testing. Fixes: 8a01a6af75 ("dm thin: prefetch missing metadata pages") Cc: stable@vger.kernel.org # 3.19+ Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm snapshot: disallow the COW and origin devices from being identicalDingXiang
Otherwise loading a "snapshot" table using the same device for the origin and COW devices, e.g.: echo "0 20971520 snapshot 253:3 253:3 P 8" | dmsetup create snap will trigger: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 [ 1958.979934] IP: [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot] [ 1958.989655] PGD 0 [ 1958.991903] Oops: 0000 [#1] SMP ... [ 1959.059647] CPU: 9 PID: 3556 Comm: dmsetup Tainted: G IO 4.5.0-rc5.snitm+ #150 ... [ 1959.083517] task: ffff8800b9660c80 ti: ffff88032a954000 task.ti: ffff88032a954000 [ 1959.091865] RIP: 0010:[<ffffffffa040efba>] [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot] [ 1959.104295] RSP: 0018:ffff88032a957b30 EFLAGS: 00010246 [ 1959.110219] RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000001 [ 1959.118180] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff880329334a00 [ 1959.126141] RBP: ffff88032a957b50 R08: 0000000000000000 R09: 0000000000000001 [ 1959.134102] R10: 000000000000000a R11: f000000000000000 R12: ffff880330884d80 [ 1959.142061] R13: 0000000000000008 R14: ffffc90001c13088 R15: ffff880330884d80 [ 1959.150021] FS: 00007f8926ba3840(0000) GS:ffff880333440000(0000) knlGS:0000000000000000 [ 1959.159047] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1959.165456] CR2: 0000000000000098 CR3: 000000032f48b000 CR4: 00000000000006e0 [ 1959.173415] Stack: [ 1959.175656] ffffc90001c13040 ffff880329334a00 ffff880330884ed0 ffff88032a957bdc [ 1959.183946] ffff88032a957bb8 ffffffffa040f225 ffff880329334a30 ffff880300000000 [ 1959.192233] ffffffffa04133e0 ffff880329334b30 0000000830884d58 00000000569c58cf [ 1959.200521] Call Trace: [ 1959.203248] [<ffffffffa040f225>] dm_exception_store_create+0x1d5/0x240 [dm_snapshot] [ 1959.211986] [<ffffffffa040d310>] snapshot_ctr+0x140/0x630 [dm_snapshot] [ 1959.219469] [<ffffffffa0005c44>] ? dm_split_args+0x64/0x150 [dm_mod] [ 1959.226656] [<ffffffffa0005ea7>] dm_table_add_target+0x177/0x440 [dm_mod] [ 1959.234328] [<ffffffffa0009203>] table_load+0x143/0x370 [dm_mod] [ 1959.241129] [<ffffffffa00090c0>] ? retrieve_status+0x1b0/0x1b0 [dm_mod] [ 1959.248607] [<ffffffffa0009e35>] ctl_ioctl+0x255/0x4d0 [dm_mod] [ 1959.255307] [<ffffffff813304e2>] ? memzero_explicit+0x12/0x20 [ 1959.261816] [<ffffffffa000a0c3>] dm_ctl_ioctl+0x13/0x20 [dm_mod] [ 1959.268615] [<ffffffff81215eb6>] do_vfs_ioctl+0xa6/0x5c0 [ 1959.274637] [<ffffffff81120d2f>] ? __audit_syscall_entry+0xaf/0x100 [ 1959.281726] [<ffffffff81003176>] ? do_audit_syscall_entry+0x66/0x70 [ 1959.288814] [<ffffffff81216449>] SyS_ioctl+0x79/0x90 [ 1959.294450] [<ffffffff8167e4ae>] entry_SYSCALL_64_fastpath+0x12/0x71 ... [ 1959.323277] RIP [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot] [ 1959.333090] RSP <ffff88032a957b30> [ 1959.336978] CR2: 0000000000000098 [ 1959.344121] ---[ end trace b049991ccad1169e ]--- Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1195899 Cc: stable@vger.kernel.org Signed-off-by: Ding Xiang <dingxiang@huawei.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm cache: make the 'mq' policy an alias for 'smq'Joe Thornber
smq seems to be performing better than the old mq policy in all situations, as well as using a quarter of the memory. Make 'mq' an alias for 'smq' when choosing a cache policy. The tunables that were present for the old mq are faked, and have no effect. mq should be considered deprecated now. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm: drop unnecessary assignment of md->queueBob Liu
md->queue and q are the same thing in dm_old_init_request_queue() and dm_mq_init_request_queue(). Also drop the temporary 'struct request_queue *q' in dm_old_init_request_queue(). Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm: reorder 'struct mapped_device' members to fix alignment and holesMike Snitzer
Saves 16 bytes by eliminating 4 4byte holes but more importantly: numerous members that crossed cachelines were fixed. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm: remove dummy definition of 'struct dm_table'Mike Snitzer
Change the map pointer in 'struct mapped_device' from 'struct dm_table __rcu *' to 'void __rcu *' to avoid the need for the dummy definition. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm: add 'dm_numa_node' module parameterMike Snitzer
Allows user to control which NUMA node the memory for DM device structures (e.g. mapped_device, request_queue, gendisk, blk_mq_tag_set) is allocated from. Defaults to NUMA_NO_NODE (-1). Allowable range is from -1 until the last online NUMA node id. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm thin metadata: remove needless newline from subtree_dec() DMERR messageMike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10dm mpath: cleanup reinstate_path() et al based on code reviewMike Snitzer
fail_path() will print a "Failing path ..." message but reinstate_path() doesn't print a "Reinstating path ...". Add that message to reinstate_path() to add symmetry and aid system debugging. Remove reinstate_path()'s check for the path_selector providing .reinstate_path hook. All path selectors provide this and any future ones must too. activate_path() calls pg_init_done() with SCSI_DH_DEV_OFFLINED but pg_init_done() doesn't expicitly handle it in its swicth statement. Add SCSI_DH_DEV_OFFLINED to the default case. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-09md/raid5: output stripe state for debugShaohua Li
Neil recently fixed an obscure race in break_stripe_batch_list. Debug would be quite convenient if we know the stripe state. This is what this patch does. Signed-off-by: Shaohua Li <shli@fb.com>
2016-03-09md/raid5: preserve STRIPE_PREREAD_ACTIVE in break_stripe_batch_listNeilBrown
break_stripe_batch_list breaks up a batch and copies some flags from the batch head to the members, preserving others. It doesn't preserve or copy STRIPE_PREREAD_ACTIVE. This is not normally a problem as STRIPE_PREREAD_ACTIVE is cleared when a stripe_head is added to a batch, and is not set on stripe_heads already in a batch. However there is no locking to ensure one thread doesn't set the flag after it has just been cleared in another. This does occasionally happen. md/raid5 maintains a count of the number of stripe_heads with STRIPE_PREREAD_ACTIVE set: conf->preread_active_stripes. When break_stripe_batch_list clears STRIPE_PREREAD_ACTIVE inadvertently this could becomes incorrect and will never again return to zero. md/raid5 delays the handling of some stripe_heads until preread_active_stripes becomes zero. So when the above mention race happens, those stripe_heads become blocked and never progress, resulting is write to the array handing. So: change break_stripe_batch_list to preserve STRIPE_PREREAD_ACTIVE in the members of a batch. URL: https://bugzilla.kernel.org/show_bug.cgi?id=108741 URL: https://bugzilla.redhat.com/show_bug.cgi?id=1258153 URL: http://thread.gmane.org/5649C0E9.2030204@zoner.cz Reported-by: Martin Svec <martin.svec@zoner.cz> (and others) Tested-by: Tom Weber <linux@junkyard.4t2.com> Fixes: 1b956f7a8f9a ("md/raid5: be more selective about distributing flags across batch.") Cc: stable@vger.kernel.org (v4.1 and later) Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-03-08bcache: fix cache_set_flush() NULL pointer dereference on OOMEric Wheeler
When bch_cache_set_alloc() fails to kzalloc the cache_set, the asyncronous closure handling tries to dereference a cache_set that hadn't yet been allocated inside of cache_set_flush() which is called by __cache_set_unregister() during cleanup. This appears to happen only during an OOM condition on bcache_register. Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net> Cc: stable@vger.kernel.org
2016-03-08bcache: cleaned up error handling around register_cache()Eric Wheeler
Fix null pointer dereference by changing register_cache() to return an int instead of being void. This allows it to return -ENOMEM or -ENODEV and enables upper layers to handle the OOM case without NULL pointer issues. See this thread: http://thread.gmane.org/gmane.linux.kernel.bcache.devel/3521 Fixes this error: gargamel:/sys/block/md5/bcache# echo /dev/sdh2 > /sys/fs/bcache/register bcache: register_cache() error opening sdh2: cannot allocate memory BUG: unable to handle kernel NULL pointer dereference at 00000000000009b8 IP: [<ffffffffc05a7e8d>] cache_set_flush+0x102/0x15c [bcache] PGD 120dff067 PUD 1119a3067 PMD 0 Oops: 0000 [#1] SMP Modules linked in: veth ip6table_filter ip6_tables (...) CPU: 4 PID: 3371 Comm: kworker/4:3 Not tainted 4.4.2-amd64-i915-volpreempt-20160213bc1 #3 Hardware name: System manufacturer System Product Name/P8H67-M PRO, BIOS 3904 04/27/2013 Workqueue: events cache_set_flush [bcache] task: ffff88020d5dc280 ti: ffff88020b6f8000 task.ti: ffff88020b6f8000 RIP: 0010:[<ffffffffc05a7e8d>] [<ffffffffc05a7e8d>] cache_set_flush+0x102/0x15c [bcache] Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net> Tested-by: Marc MERLIN <marc@merlins.org> Cc: <stable@vger.kernel.org>
2016-03-08bcache: fix race of writeback thread starting before complete initializationEric Wheeler
The bch_writeback_thread might BUG_ON in read_dirty() if dc->sb==BDEV_STATE_DIRTY and bch_sectors_dirty_init has not yet completed its related initialization. This patch downs the dc->writeback_lock until after initialization is complete, thus preventing bch_writeback_thread from proceeding prematurely. See this thread: http://thread.gmane.org/gmane.linux.kernel.bcache.devel/3453 Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net> Tested-by: Marc MERLIN <marc@merlins.org> Cc: <stable@vger.kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-03-07md/bitmap: remove redundant checkEric Engestrom
daemon_sleep is an unsigned, so testing if it's 0 or less than 1 does the same thing. Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-02-26MD: warn for potential deadlockShaohua Li
The personality thread shouldn't call mddev_suspend(). Because mddev_suspend() will for all IO finish, but IO is handled in personality thread, so this could cause deadlock. To trigger this early, add a warning if mddev_suspend() is called from personality thread. Suggested-by: NeilBrown <neilb@suse.com> Cc: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-02-26md: Drop sending a change uevent when stoppingSebastian Parschauer
When stopping an MD device, then its device node /dev/mdX may still exist afterwards or it is recreated by udev. The next open() call can lead to creation of an inoperable MD device. The reason for this is that a change event (KOBJ_CHANGE) is sent to udev which races against the remove event (KOBJ_REMOVE) from md_free(). So drop sending the change event. A change is likely also required in mdadm as many versions send the change event to udev as well. Neil mentioned the change event is a workaround for old kernel Commit: 934d9c23b4c7 ("md: destroy partitions and notify udev when md array is stopped.") new mdadm can handle device remove now, so this isn't required any more. Cc: NeilBrown <neilb@suse.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Jes Sorensen <Jes.Sorensen@redhat.com> Signed-off-by: Sebastian Parschauer <sebastian.riemer@profitbricks.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-02-26RAID5: revert e9e4c377e2f563 to fix a livelockShaohua Li
Revert commit e9e4c377e2f563(md/raid5: per hash value and exclusive wait_for_stripe) The problem is raid5_get_active_stripe waits on conf->wait_for_stripe[hash]. Assume hash is 0. My test release stripes in this order: - release all stripes with hash 0 - raid5_get_active_stripe still sleeps since active_stripes > max_nr_stripes * 3 / 4 - release all stripes with hash other than 0. active_stripes becomes 0 - raid5_get_active_stripe still sleeps, since nobody wakes up wait_for_stripe[0] The system live locks. The problem is active_stripes isn't a per-hash count. Revert the patch makes the live lock go away. Cc: stable@vger.kernel.org (v4.2+) Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com> Cc: NeilBrown <neilb@suse.de> Signed-off-by: Shaohua Li <shli@fb.com>
2016-02-26RAID5: check_reshape() shouldn't call mddev_suspendShaohua Li
check_reshape() is called from raid5d thread. raid5d thread shouldn't call mddev_suspend(), because mddev_suspend() waits for all IO finish but IO is handled in raid5d thread, we could easily deadlock here. This issue is introduced by 738a273 ("md/raid5: fix allocation of 'scribble' array.") Cc: stable@vger.kernel.org (v4.1+) Reported-and-tested-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-02-25md/raid5: Compare apples to apples (or sectors to sectors)Jes Sorensen
'max_discard_sectors' is in sectors, while 'stripe' is in bytes. This fixes the problem where DISCARD would get disabled on some larger RAID5 configurations (6 or more drives in my testing), while it worked as expected with smaller configurations. Fixes: 620125f2bf8 ("MD: raid5 trim support") Cc: stable@vger.kernel.org v3.7+ Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-02-22dm mpath: remove __pgpath_busy forward declaration, rename to pgpath_busyMike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm mpath: switch from 'unsigned' to 'bool' for flags where appropriateMike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm round robin: use percpu 'repeat_count' and 'current_path'Mike Snitzer
Now that dm-mpath core is lockless in the per-IO fast path it is critical, for performance, to have the .select_path hook (rr_select_path) also be as lockless as possible. The new percpu members of 'struct selector' allow for lockless support of 'repeat_count' governed repeat use of a previously selected path. If a path fails while it is 'current_path' the worst case is concurrent IO might be mapped to the failed path until the .fail_path hook (rr_fail_path) is called. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm path selector: remove 'repeat_count' return from .select_path hookMike Snitzer
If a path selector has any use for a repeat_count it should be handled locally and not depend on the dm-mpath core to be concerned with it. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm mpath: push path selector locking down to path selectorsMike Snitzer
Proper locking of the lists used by the path selectors should be handled within the selectors (relying on dm-mpath.c code's use of the m->lock spinlock was reckless). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm mpath: remove repeat_count support from multipath coreMike Snitzer
Preparation for making __multipath_map() avoid taking the m->lock spinlock -- in favor of using RCU locking. repeat_count was primarily for bio-based DM multipath's benefit. There is really no need for it anymore now that DM multipath is request-based. As such, repeat_count > 1 is no longer honored and a warning is displayed if the user attempts to use a value > 1. This is a temporary change for the round-robin path-selector (as a later commit will restore its support for repeat_count > 1). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm mpath: remove unnecessary casts in front of ti->privateMike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm mpath: use blk_mq_alloc_request() and blk_mq_free_request() directlyMike Snitzer
There isn't any need to support both old .request_fn and blk-mq paths in the blk-mq specific portion of __multipath_map(). Call blk_mq_alloc_request() directly rather than use blk_get_request(). Similarly, call blk_mq_free_request(), rather than blk_put_request(), in multipath_release_clone(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm mpath: cleanup 'struct dm_mpath_io' management codeMike Snitzer
Refactor and rename existing interfaces to be more specific and self-documenting. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm mpath: use blk-mq pdu for per-request 'struct dm_mpath_io'Mike Snitzer
Allow the multipath target to avoid making small allocations for each 'struct dm_mpath_io' that is needed for each request. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: allow immutable request-based targets to use blk-mq pduMike Snitzer
This will allow DM multipath to use a portion of the blk-mq pdu space for target data (e.g. struct dm_mpath_io). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: rename target's per_bio_data_size to per_io_data_sizeMike Snitzer
Request-based DM will also make use of per_bio_data_size. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: distinquish old .request_fn (dm-old) vs dm-mq request-based DMMike Snitzer
Rename various methods to have either a "dm_old" or "dm_mq" prefix. Improve code comments to assist with understanding the duality of code that handles both "dm_old" and "dm_mq" cases. It is no much easier to quickly look at the code and _know_ that a given method is either 1) "dm_old" only 2) "dm_mq" only 3) common to both. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: remove support for stacking dm-mq on .request_fn device(s)Mike Snitzer
Remove all fiddley code that propped up this support for a blk-mq request-queue ontop of all .request_fn devices. Testing has proven this niche request-based dm-mq mode to be buggy, when testing fault tolerance with DM multipath, and there is no point trying to preserve it. Should help improve efficiency of pure dm-mq code and make code maintenance less delicate. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: fix a couple locking issues with use of block interfacesMike Snitzer
old_stop_queue() was checking blk_queue_stopped() without holding the q->queue_lock. dm_requeue_original_request() needed to check blk_queue_stopped(), with q->queue_lock held, before calling blk_mq_kick_requeue_list(). And a side-effect of that change is start_queue() must also call blk_mq_kick_requeue_list(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: allocate blk_mq_tag_set rather than embed in mapped_deviceMike Snitzer
The blk_mq_tag_set is only needed for dm-mq support. There is point wasting space in 'struct mapped_device' for non-dm-mq devices. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> # check kzalloc return
2016-02-22dm: add 'dm_mq_nr_hw_queues' and 'dm_mq_queue_depth' module paramsMike Snitzer
Allow user to change these values via module params or sysfs. 'dm_mq_nr_hw_queues' defaults to 1 (max 32). 'dm_mq_queue_depth' defaults to 2048 (up from 64, which proved far too small under moderate sized workloads -- the dm-multipath device would continuously block waiting for tags (requests) to become available). The maximum is BLK_MQ_MAX_DEPTH (currently 10240). Keep in mind the total number of pre-allocated requests per request-based dm-mq device is 'dm_mq_nr_hw_queues' * 'dm_mq_queue_depth' (currently 2048). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: optimize dm_request_fn()Mike Snitzer
DM multipath is the only request-based DM target -- which only supports tables with a single target that is immutable. Leverage this fact in dm_request_fn(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: optimize dm_mq_queue_rq()Mike Snitzer
DM multipath is the only dm-mq target. But that aside, request-based DM only supports tables with a single target that is immutable. Leverage this fact in dm_mq_queue_rq() by using the 'immutable_target' stored in the mapped_device when the table was made active. This saves the need to even take the read-side of the SRCU via dm_{get,put}_live_table. If the active DM table does not have an immutable target (e.g. "error" target was swapped in) then fallback to the slow-path where the target is looked up from the live table. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: set DM_TARGET_WILDCARD feature on "error" targetMike Snitzer
The DM_TARGET_WILDCARD feature indicates that the "error" target may replace any target; even immutable targets. This feature will be useful to preserve the ability to replace the "multipath" target even once it is formally converted over to having the DM_TARGET_IMMUTABLE feature. Also, implicit in the DM_TARGET_WILDCARD feature flag being set is that .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined in the target_type. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: cleanup dm_any_congested()Mike Snitzer
The request-based DM support for checking queue congestion doesn't require access to the live DM table. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22dm: remove unused dm_get_rq_mapinfo()Mike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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