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authorDan Williams <dan.j.williams@intel.com>2015-10-21 13:20:12 -0400
committerJens Axboe <axboe@fb.com>2015-10-21 14:43:41 -0600
commit3ef28e83ab15799742e55fd13243a5f678b04242 (patch)
treee594552aaeaafed8468ae96e54992cf1697a1fc7 /block/blk-mq-sysfs.c
parent4cfc766e07a5ed709a9d5289c8644fe78e9f24de (diff)
downloadlinux-linaro-stable-3ef28e83ab15799742e55fd13243a5f678b04242.tar.gz
block: generic request_queue reference counting
Allow pmem, and other synchronous/bio-based block drivers, to fallback on a per-cpu reference count managed by the core for tracking queue live/dead state. The existing per-cpu reference count for the blk_mq case is promoted to be used in all block i/o scenarios. This involves initializing it by default, waiting for it to drop to zero at exit, and holding a live reference over the invocation of q->make_request_fn() in generic_make_request(). The blk_mq code continues to take its own reference per blk_mq request and retains the ability to freeze the queue, but the check that the queue is frozen is moved to generic_make_request(). This fixes crash signatures like the following: BUG: unable to handle kernel paging request at ffff880140000000 [..] Call Trace: [<ffffffff8145e8bf>] ? copy_user_handle_tail+0x5f/0x70 [<ffffffffa004e1e0>] pmem_do_bvec.isra.11+0x70/0xf0 [nd_pmem] [<ffffffffa004e331>] pmem_make_request+0xd1/0x200 [nd_pmem] [<ffffffff811c3162>] ? mempool_alloc+0x72/0x1a0 [<ffffffff8141f8b6>] generic_make_request+0xd6/0x110 [<ffffffff8141f966>] submit_bio+0x76/0x170 [<ffffffff81286dff>] submit_bh_wbc+0x12f/0x160 [<ffffffff81286e62>] submit_bh+0x12/0x20 [<ffffffff813395bd>] jbd2_write_superblock+0x8d/0x170 [<ffffffff8133974d>] jbd2_mark_journal_empty+0x5d/0x90 [<ffffffff813399cb>] jbd2_journal_destroy+0x24b/0x270 [<ffffffff810bc4ca>] ? put_pwq_unlocked+0x2a/0x30 [<ffffffff810bc6f5>] ? destroy_workqueue+0x225/0x250 [<ffffffff81303494>] ext4_put_super+0x64/0x360 [<ffffffff8124ab1a>] generic_shutdown_super+0x6a/0xf0 Cc: Jens Axboe <axboe@kernel.dk> Cc: Keith Busch <keith.busch@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Suggested-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-mq-sysfs.c')
-rw-r--r--block/blk-mq-sysfs.c6
1 files changed, 0 insertions, 6 deletions
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 788fffd9b409..6f57a110289c 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -413,12 +413,6 @@ static void blk_mq_sysfs_init(struct request_queue *q)
kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
}
-/* see blk_register_queue() */
-void blk_mq_finish_init(struct request_queue *q)
-{
- percpu_ref_switch_to_percpu(&q->mq_usage_counter);
-}
-
int blk_mq_register_disk(struct gendisk *disk)
{
struct device *dev = disk_to_dev(disk);