kernel/linux.git/include/linux/blkdev.h, branch v5.3.9

block: make rq sector size accessible for block stats

2019-10-05T13:12:06+00:00

[ Upstream commit 3d24430694077313c75c6b89f618db09943621e4 ] Currently rq->data_len will be decreased by partial completion or zeroed by completion, so when blk_stat_add() is invoked, data_len will be zero and there will never be samples in poll_cb because blk_mq_poll_stats_bkt() will return -1 if data_len is zero. We could move blk_stat_add() back to __blk_mq_complete_request(), but that would make the effort of trying to call ktime_get_ns() once in vain. Instead we can reuse throtl_size field, and use it for both block stats and block throttle, and adjust the logic in blk_mq_poll_stats_bkt() accordingly. Fixes: 4bc6339a583c ("block: move blk_stat_add() to __blk_mq_end_request()") Tested-by: Pavel Begunkov Signed-off-by: Hou Tao Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block: Limit zone array allocation size

2019-07-12T02:04:40+00:00

Limit the size of the struct blk_zone array used in blk_revalidate_disk_zones() to avoid memory allocation failures leading to disk revalidation failure. Also further reduce the likelyhood of such failures by using kvcalloc() (that is vmalloc()) instead of allocating contiguous pages with alloc_pages(). Fixes: 515ce6061312 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation") Fixes: e76239a3748c ("block: add a report_zones method") Cc: stable@vger.kernel.org Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Signed-off-by: Damien Le Moal Signed-off-by: Jens Axboe

block: Kill gfp_t argument of blkdev_report_zones()

2019-07-12T02:04:37+00:00

Only GFP_KERNEL and GFP_NOIO are used with blkdev_report_zones(). In preparation of using vmalloc() for large report buffer and zone array allocations used by this function, remove its "gfp_t gfp_mask" argument and rely on the caller context to use memalloc_noio_save/restore() where necessary (block layer zone revalidation and dm-zoned I/O error path). Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Signed-off-by: Damien Le Moal Signed-off-by: Jens Axboe

block: Fix potential overflow in blk_report_zones()

2019-07-10T15:00:57+00:00

For large values of the number of zones reported and/or large zone sizes, the sector increment calculated with blk_queue_zone_sectors(q) * n in blk_report_zones() loop can overflow the unsigned int type used for the calculation as both "n" and blk_queue_zone_sectors() value are unsigned int. E.g. for a device with 256 MB zones (524288 sectors), overflow happens with 8192 or more zones reported. Changing the return type of blk_queue_zone_sectors() to sector_t, fixes this problem and avoids overflow problem for all other callers of this helper too. The same change is also applied to the bdev_zone_sectors() helper. Fixes: e76239a3748c ("block: add a report_zones method") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Signed-off-by: Jens Axboe

block: add centralize REQ_OP_XXX to string helper

2019-06-20T19:03:51+00:00

In order to centralize the REQ_OP_XXX to string conversion which can be used in the block layer and different places in the kernel like f2fs, this patch adds a new helper function along with an array similar to the one present in the blk-mq-debugfs.c. We keep this helper functionality centralize under blk-core.c instead of blk-mq-debugfs.c since blk-core.c is configured using CONFIG_BLOCK and it will not be dependent on blk-mq-debugfs.c which is configured using CONFIG_BLK_DEBUG_FS. Next patch adjusts the code in the blk-mq-debugfs.c with newly introduced helper. Reviewed-by: Bart Van Assche Signed-off-by: Chaitanya Kulkarni Signed-off-by: Jens Axboe

block: remove the bi_phys_segments field in struct bio

2019-06-20T16:29:22+00:00

We only need the number of segments in the blk-mq submission path. Remove the field from struct bio, and return it from a variant of blk_queue_split instead of that it can passed as an argument to those functions that need the value. This also means we stop recounting segments except for cloning and partial segments. To keep the number of arguments in this how path down remove pointless struct request_queue arguments from any of the functions that had it and grew a nr_segs argument. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: remove blk_init_request_from_bio

2019-06-20T16:29:22+00:00

lightnvm should have never used this function, as it is sending passthrough requests, so switch it to blk_rq_append_bio like all the other passthrough request users. Inline blk_init_request_from_bio into the only remaining caller. Reviewed-by: Hannes Reinecke Reviewed-by: Minwoo Im Reviewed-by: Javier González Reviewed-by: Matias Bjørling Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

blk-core: Remove blk_end_request*() declarations

2019-06-20T09:26:19+00:00

Commit a1ce35fa49852db60fc6e268 ("block: remove dead elevator code") deleted blk_end_request() and friends, but some declaration are still left. Purge them. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe

block: move tag field position in struct request

2019-06-20T09:17:05+00:00

__data_len and __sector are internal fields which should not be accessed directly in driver-level like the comment above it. But, tag field can be accessed by driver level directly so that we need to make the comment right by moving it to some other place. Cc: Jens Axboe Cc: linux-block@vger.kernel.org Signed-off-by: Minwoo Im Reviewed-by: Chaitanya Kulkarni Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

blk-mq: fix hang caused by freeze/unfreeze sequence

2019-05-23T16:25:26+00:00

The following is a description of a hang in blk_mq_freeze_queue_wait(). The hang happens on attempt to freeze a queue while another task does queue unfreeze. The root cause is an incorrect sequence of percpu_ref_resurrect() and percpu_ref_kill() and as a result those two can be swapped: CPU#0 CPU#1 ---------------- ----------------- q1 = blk_mq_init_queue(shared_tags) q2 = blk_mq_init_queue(shared_tags): blk_mq_add_queue_tag_set(shared_tags): blk_mq_update_tag_set_depth(shared_tags): list_for_each_entry() blk_mq_freeze_queue(q1) > percpu_ref_kill() > blk_mq_freeze_queue_wait() blk_cleanup_queue(q1) blk_mq_freeze_queue(q1) > percpu_ref_kill() ^^^^^^ freeze_depth can't guarantee the order blk_mq_unfreeze_queue() > percpu_ref_resurrect() > blk_mq_freeze_queue_wait() ^^^^^^ Hang here!!!! This wrong sequence raises kernel warning: percpu_ref_kill_and_confirm called more than once on blk_queue_usage_counter_release! WARNING: CPU: 0 PID: 11854 at lib/percpu-refcount.c:336 percpu_ref_kill_and_confirm+0x99/0xb0 But the most unpleasant effect is a hang of a blk_mq_freeze_queue_wait(), which waits for a zero of a q_usage_counter, which never happens because percpu-ref was reinited (instead of being killed) and stays in PERCPU state forever. How to reproduce: - "insmod null_blk.ko shared_tags=1 nr_devices=0 queue_mode=2" - cpu0: python Script.py 0; taskset the corresponding process running on cpu0 - cpu1: python Script.py 1; taskset the corresponding process running on cpu1 Script.py: ------ #!/usr/bin/python3 import os import sys while True: on = "echo 1 > /sys/kernel/config/nullb/%s/power" % sys.argv[1] off = "echo 0 > /sys/kernel/config/nullb/%s/power" % sys.argv[1] os.system(on) os.system(off) ------ This bug was first reported and fixed by Roman, previous discussion: [1] Message id: 1443287365-4244-7-git-send-email-akinobu.mita@gmail.com [2] Message id: 1443563240-29306-6-git-send-email-tj@kernel.org [3] https://patchwork.kernel.org/patch/9268199/ Reviewed-by: Hannes Reinecke Reviewed-by: Ming Lei Reviewed-by: Bart Van Assche Reviewed-by: Christoph Hellwig Signed-off-by: Roman Pen Signed-off-by: Bob Liu Signed-off-by: Jens Axboe