- 03 Jun, 2021 3 commits
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Bart Van Assche authored
Although the original intent was to use blk_update_request() in stacking block drivers only, it is used much more widely today. Reflect this in the documentation block above this function. See also: * commit 32fab448 ("block: add request update interface"). * commit 2e60e022 ("block: clean up request completion API"). * commit ed6565e7 ("block: handle partial completions for special payload requests"). Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Signed-off-by:
Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210519175226.8853-1-bvanassche@acm.orgSigned-off-by:
Jens Axboe <axboe@kernel.dk>
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Jan Kara authored
Provided the device driver does not implement dispatch budget accounting (which only SCSI does) the loop in __blk_mq_do_dispatch_sched() pulls requests from the IO scheduler as long as it is willing to give out any. That defeats scheduling heuristics inside the scheduler by creating false impression that the device can take more IO when it in fact cannot. For example with BFQ IO scheduler on top of virtio-blk device setting blkio cgroup weight has barely any impact on observed throughput of async IO because __blk_mq_do_dispatch_sched() always sucks out all the IO queued in BFQ. BFQ first submits IO from higher weight cgroups but when that is all dispatched, it will give out IO of lower weight cgroups as well. And then we have to wait for all this IO to be dispatched to the disk (which means lot of it actually has to complete) before the IO scheduler is queried again for dispatching more requests. This completely destroys any service differentiation. So grab request tag for a request pulled out of the IO scheduler already in __blk_mq_do_dispatch_sched() and do not pull any more requests if we cannot get it because we are unlikely to be able to dispatch it. That way only single request is going to wait in the dispatch list for some tag to free. Reviewed-by:
Ming Lei <ming.lei@redhat.com> Signed-off-by:
Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210603104721.6309-1-jack@suse.czSigned-off-by:
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Colin Ian King authored
The error handling on a nullb->disk allocation currently jumps to out_cleanup_disk that calls blk_cleanup_disk with a null pointer causing a null pointer dereference issue. Fix this by jumping to out_cleanup_tags instead. Addresses-Coverity: ("Dereference after null check") Fixes: 132226b3 ("null_blk: convert to blk_alloc_disk/blk_cleanup_disk") Signed-off-by:Colin Ian King <colin.king@canonical.com> Reviewed-by:
Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210602100659.11058-1-colin.king@canonical.comSigned-off-by:
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- 01 Jun, 2021 34 commits
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Christoph Hellwig authored
Just opencode the xa_load in the callers, as none of them actually needs a reference to the bdev. Signed-off-by:
Hannes Reinecke <hare@suse.de> Reviewed-by:
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Christoph Hellwig authored
Add a helper to find the dev_t for a disk + partno tuple. Signed-off-by:
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Christoph Hellwig authored
The bd_part_count value only makes sense for whole devices, so move it to struct gendisk and give it a more descriptive name. Signed-off-by:
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Christoph Hellwig authored
Split __blkdev_put into one helper for the whole device, and one for partitions as well as another shared helper for flushing the block device inode mapping. Signed-off-by:
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Christoph Hellwig authored
Keep in the callers and thus remove the for_part argument. This mirrors what is done on the blkdev_get side and slightly simplifies blkdev_get_part as well. Signed-off-by:
Ming Lei <ming.lei@rehat.com> Link: https://lore.kernel.org/r/20210525061301.2242282-5-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
Replace the per-block device bd_mutex with a per-gendisk open_mutex, thus simplifying locking wherever we deal with partitions. Signed-off-by:
Roger Pau Monné <roger.pau@citrix.com> Link: https://lore.kernel.org/r/20210525061301.2242282-4-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
Do the early unlocked syncing even earlier to move more code out of the recursive path. Signed-off-by:
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Christoph Hellwig authored
Split __blkdev_get into one helper for the whole device, and one for opening partitions. This removes the (bounded) recursion when opening a partition. Signed-off-by:
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Christoph Hellwig authored
blk_alloc_queue is just an internal helper now, unexport it and remove it from the public header. Signed-off-by:
Ulf Hansson <ulf.hansson@linaro.org> Link: https://lore.kernel.org/r/20210521055116.1053587-27-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
Convert the null_blk driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Note that the blk-mq mode is left with its own allocations scheme, to be handled later. Signed-off-by:
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Christoph Hellwig authored
Convert the xpram driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the dcssblk driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the ps3vram driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the n64cart driver to use the blk_alloc_disk helper to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the simdisk driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the nfblock driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by:
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Christoph Hellwig authored
Convert the nvme-multipath driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the nvdimm-pmem driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the nvdimm-btt driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the nvdimm-blk driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the md driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the dm driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the bcache driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
Coly Li <colyli@suse.de> Reviewed-by:
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Christoph Hellwig authored
Convert the lightnvm driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the zram driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the rsxx driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the pktcdvd driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the drbd driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. Signed-off-by:
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Christoph Hellwig authored
Convert the brd driver to use the blk_alloc_disk and blk_cleanup_disk helpers to simplify gendisk and request_queue allocation. This also allows to remove the request_queue pointer in struct request_queue, and to simplify the initialization as blk_cleanup_disk can be called on any disk returned from blk_alloc_disk. Signed-off-by:
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Christoph Hellwig authored
Add two new APIs to allocate and free a gendisk including the request_queue for use with BIO based drivers. This is to avoid boilerplate code in drivers. Signed-off-by:
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Christoph Hellwig authored
Add a flag to indicate that __device_add_disk did grab a queue reference so that disk_release only drops it if we actually had it. This sort out one of the major pitfals with partially initialized gendisk that a lot of drivers did get wrong or still do. Signed-off-by:
Luis Chamberlain <mcgrof@kernel.org> Reviewed-by:
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Christoph Hellwig authored
Automatically set the GENHD_FL_EXT_DEVT flag for all disks allocated without an explicit number of minors. This is what all new block drivers should do, so make sure it is the default without boilerplate code. Signed-off-by:
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Christoph Hellwig authored
Keep this together with the first place that actually looks at ->minors and prepare for not passing a minors argument to alloc_disk. Signed-off-by:
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Christoph Hellwig authored
Untangle the mess around blk_alloc_devt by moving the check for the used allocation scheme into the callers. Signed-off-by:
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- 24 May, 2021 3 commits
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John Garry authored
The tags used for an IO scheduler are currently per hctx. As such, when q->nr_hw_queues grows, so does the request queue total IO scheduler tag depth. This may cause problems for SCSI MQ HBAs whose total driver depth is fixed. Ming and Yanhui report higher CPU usage and lower throughput in scenarios where the fixed total driver tag depth is appreciably lower than the total scheduler tag depth: https://lore.kernel.org/linux-block/440dfcfc-1a2c-bd98-1161-cec4d78c6dfc@huawei.com/T/#mc0d6d4f95275a2743d1c8c3e4dc9ff6c9aa3a76b In that scenario, since the scheduler tag is got first, much contention is introduced since a driver tag may not be available after we have got the sched tag. Improve this scenario by introducing request queue-wide tags for when a tagset-wide sbitmap is used. The static sched requests are still allocated per hctx, as requests are initialised per hctx, as in blk_mq_init_request(..., hctx_idx, ...) -> set->ops->init_request(.., hctx_idx, ...). For simplicity of resizing the request queue sbitmap when updating the request queue depth, just init at the max possible size, so we don't need to deal with the possibly with swapping out a new sbitmap for old if we need to grow. Signed-off-by:
John Garry <john.garry@huawei.com> Reviewed-by:
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John Garry authored
The tag allocation code to alloc the sbitmap pairs is common for regular bitmaps tags and shared sbitmap, so refactor into a common function. Also remove superfluous "flags" argument from blk_mq_init_shared_sbitmap(). Signed-off-by:
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Ming Lei authored
Before we free request queue, clearing flush request reference in tags->rqs[], so that potential UAF can be avoided. Based on one patch written by David Jeffery. Tested-by:
David Jeffery <djeffery@redhat.com> Signed-off-by:
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