kernel/linux.git/block/elevator.c, branch v6.6.132

block: Fix elevator_get_default() checking for NULL q->tag_set

2024-11-17T14:08:56+00:00

[ Upstream commit b402328a24ee7193a8ab84277c0c90ae16768126 ] elevator_get_default() and elv_support_iosched() both check for whether or not q->tag_set is non-NULL, however it's not possible for them to be NULL. This messes up some static checkers, as the checking of tag_set isn't consistent. Remove the checks, which both simplifies the logic and avoids checker errors. Signed-off-by: SurajSonawane2415 Link: https://lore.kernel.org/r/20241007111416.13814-1-surajsonawane0215@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

blk-mq: release scheduler resource when request completes

2023-08-19T13:47:17+00:00

Chuck reported [1] an IO hang problem on NFS exports that reside on SATA devices and bisected to commit 615939a2ae73 ("blk-mq: defer to the normal submission path for post-flush requests"). We analysed the IO hang problem, found there are two postflush requests waiting for each other. The first postflush request completed the REQ_FSEQ_DATA sequence, so go to the REQ_FSEQ_POSTFLUSH sequence and added in the flush pending list, but failed to blk_kick_flush() because of the second postflush request which is inflight waiting in scheduler queue. The second postflush waiting in scheduler queue can't be dispatched because the first postflush hasn't released scheduler resource even though it has completed by itself. Fix it by releasing scheduler resource when the first postflush request completed, so the second postflush can be dispatched and completed, then make blk_kick_flush() succeed. While at it, remove the check for e->ops.finish_request, as all schedulers set that. Reaffirm this requirement by adding a WARN_ON_ONCE() at scheduler registration time, just like we do for insert_requests and dispatch_request. [1] https://lore.kernel.org/all/7A57C7AE-A51A-4254-888B-FE15CA21F9E9@oracle.com/ Link: https://lore.kernel.org/linux-block/20230819031206.2744005-1-chengming.zhou@linux.dev/ Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202308172100.8ce4b853-oliver.sang@intel.com Fixes: 615939a2ae73 ("blk-mq: defer to the normal submission path for post-flush requests") Reported-by: Chuck Lever Signed-off-by: Chengming Zhou Tested-by: Chuck Lever Link: https://lore.kernel.org/r/20230813152325.3017343-1-chengming.zhou@linux.dev [axboe: folded in incremental fix and added tags] Signed-off-by: Jens Axboe

block: Replace all non-returning strlcpy with strscpy

2023-06-01T15:13:31+00:00

strlcpy() reads the entire source buffer first. This read may exceed the destination size limit. This is both inefficient and can lead to linear read overflows if a source string is not NUL-terminated [1]. In an effort to remove strlcpy() completely [2], replace strlcpy() here with strscpy(). No return values were used, so direct replacement is safe. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [2] https://github.com/KSPP/linux/issues/89 Signed-off-by: Azeem Shaikh Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20230530155608.272266-1-azeemshaikh38@gmail.com Signed-off-by: Jens Axboe

block: make kobj_type structures constant

2023-02-09T16:38:16+00:00

Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.") the driver core allows the usage of const struct kobj_type. Take advantage of this to constify the structure definitions to prevent modification at runtime. Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/r/20230208-kobj_type-block-v1-1-0b3eafd7d983@weissschuh.net Signed-off-by: Jens Axboe

block: untangle request_queue refcounting from sysfs

2022-11-30T18:09:00+00:00

The kobject embedded into the request_queue is used for the queue directory in sysfs, but that is a child of the gendisks directory and is intimately tied to it. Move this kobject to the gendisk and use a refcount_t in the request_queue for the actual request_queue refcounting that is completely unrelated to the device model. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20221114042637.1009333-5-hch@lst.de Signed-off-by: Jens Axboe

block: use bool as the return type of elv_iosched_allow_bio_merge

2022-11-29T17:53:10+00:00

We have bool type now, update the old signature. Signed-off-by: Jinlong Chen Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/0db0a0298758d60d0f4df8b7126ac6a381e5a5bb.1669736350.git.nickyc975@zju.edu.cn Signed-off-by: Jens Axboe

block: replace "len+name" with "name+len" in elv_iosched_show

2022-11-29T17:53:10+00:00

The "pointer + offset" pattern is more resonable. Signed-off-by: Jinlong Chen Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/d9beaee71b14f7b2a39ab0db6458dc0f7d961ceb.1669736350.git.nickyc975@zju.edu.cn Signed-off-by: Jens Axboe

block: always use 'e' when printing scheduler name

2022-11-29T17:53:10+00:00

Printing e->elevator_name in all cases improves the readability, and 'e' and 'cur' are identical in this branch. Suggested-by: Christoph Hellwig Signed-off-by: Jinlong Chen Link: https://lore.kernel.org/r/4bae180ffbac608ea0cf46ffa9739ce0973b60aa.1669736350.git.nickyc975@zju.edu.cn Signed-off-by: Jens Axboe

block: replace continue with else-if in elv_iosched_show

2022-11-29T17:53:06+00:00

else-if is more readable than continue here. Signed-off-by: Jinlong Chen Link: https://lore.kernel.org/r/77ac19ba556efd2c8639a6396eb4203c59bc13d6.1669736350.git.nickyc975@zju.edu.cn Signed-off-by: Jens Axboe

block: include 'none' for initial elv_iosched_show call

2022-11-29T17:48:59+00:00

This makes the printing order of the io schedulers consistent, and removes a redundant q->elevator check. Signed-off-by: Jinlong Chen Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/bdd7083ed4f232e3285f39081e3c5f30b20b8da2.1669736350.git.nickyc975@zju.edu.cn Signed-off-by: Jens Axboe