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2020-05-27block: reduce part_stat_lock() scopeChristoph Hellwig1-1/+2
We only need the stats lock (aka preempt_disable()) for updating the states, not for looking up or dropping the hd_struct reference. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-27block: account merge of two requestsKonstantin Khlebnikov1-7/+5
Also rename blk_account_io_merge() into blk_account_io_merge_request() to distinguish it from merging request and bio. [hch: rebased] Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-19block: don't call part_{inc,dec}_in_flight for blk-mq devicesChristoph Hellwig1-2/+0
part_inc_in_flight and part_dec_in_flight are no-ops for blk-mq queues, so remove the calls in purely blk-mq callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-14block: Inline encryption support for blk-mqSatya Tangirala1-0/+11
We must have some way of letting a storage device driver know what encryption context it should use for en/decrypting a request. However, it's the upper layers (like the filesystem/fscrypt) that know about and manages encryption contexts. As such, when the upper layer submits a bio to the block layer, and this bio eventually reaches a device driver with support for inline encryption, the device driver will need to have been told the encryption context for that bio. We want to communicate the encryption context from the upper layer to the storage device along with the bio, when the bio is submitted to the block layer. To do this, we add a struct bio_crypt_ctx to struct bio, which can represent an encryption context (note that we can't use the bi_private field in struct bio to do this because that field does not function to pass information across layers in the storage stack). We also introduce various functions to manipulate the bio_crypt_ctx and make the bio/request merging logic aware of the bio_crypt_ctx. We also make changes to blk-mq to make it handle bios with encryption contexts. blk-mq can merge many bios into the same request. These bios need to have contiguous data unit numbers (the necessary changes to blk-merge are also made to ensure this) - as such, it suffices to keep the data unit number of just the first bio, since that's all a storage driver needs to infer the data unit number to use for each data block in each bio in a request. blk-mq keeps track of the encryption context to be used for all the bios in a request with the request's rq_crypt_ctx. When the first bio is added to an empty request, blk-mq will program the encryption context of that bio into the request_queue's keyslot manager, and store the returned keyslot in the request's rq_crypt_ctx. All the functions to operate on encryption contexts are in blk-crypto.c. Upper layers only need to call bio_crypt_set_ctx with the encryption key, algorithm and data_unit_num; they don't have to worry about getting a keyslot for each encryption context, as blk-mq/blk-crypto handles that. Blk-crypto also makes it possible for request-based layered devices like dm-rq to make use of inline encryption hardware by cloning the rq_crypt_ctx and programming a keyslot in the new request_queue when necessary. Note that any user of the block layer can submit bios with an encryption context, such as filesystems, device-mapper targets, etc. Signed-off-by: Satya Tangirala <satyat@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-29block: replace BIO_QUEUE_ENTERED with BIO_CGROUP_ACCTChristoph Hellwig1-10/+0
BIO_QUEUE_ENTERED is only used for cgroup accounting now, so rename the flag and move setting it into the cgroup code. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-22block: move dma_pad handling from blk_rq_map_sg into the callersChristoph Hellwig1-8/+0
There are only two callers of blk_rq_map_sg/__blk_rq_map_sg that set the dma_pad value in the queue. Move the handling into those callers instead of burdening the common code, and move the ->extra_len field from struct request to struct scsi_cmnd. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-22block: move dma drain handling to scsiChristoph Hellwig1-14/+0
Don't burden the common block code with with specifics of the libata DMA draining mechanism. Instead move most of the code to the scsi midlayer. That also means the nr_phys_segments adjustments in the blk-mq fast path can go away entirely, given that SCSI never looks at nr_phys_segments after mapping the request to a scatterlist. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-22block: provide a blk_rq_map_sg variant that returns the last elementChristoph Hellwig1-13/+12
To be able to move some of the special purpose hacks in blk_rq_map_sg into the callers we need a variant that returns the last mapped S/G list element to the caller. Add that variant as __blk_rq_map_sg and make blk_rq_map_sg a trivial inline wrapper around it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-22block: remove RQF_COPY_USERChristoph Hellwig1-2/+1
The RQF_COPY_USER is set for bio where the passthrough request mapping helpers decided that bounce buffering is required. It is then used to pad scatterlist for drivers that required it. But given that non-passthrough requests are per definition aligned, and directly mapped pass-through request must be aligned it is not actually required at all. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-14block: fix get_max_segment_size() overflow on 32bit archMing Lei1-2/+7
Commit 429120f3df2d starts to take account of segment's start dma address when computing max segment size, and data type of 'unsigned long' is used to do that. However, the segment mask may be 0xffffffff, so the figured out segment size may be overflowed in case of zero physical address on 32bit arch. Fix the issue by returning queue_max_segment_size() directly when that happens. Fixes: 429120f3df2d ("block: fix splitting segments on boundary masks") Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Cc: Christoph Hellwig <hch@lst.de> Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-12-30block: fix splitting segments on boundary masksMing Lei1-9/+9
We ran into a problem with a mpt3sas based controller, where we would see random (and hard to reproduce) file corruption). The issue seemed specific to this controller, but wasn't specific to the file system. After a lot of debugging, we find out that it's caused by segments spanning a 4G memory boundary. This shouldn't happen, as the default setting for segment boundary masks is 4G. Turns out there are two issues in get_max_segment_size(): 1) The default segment boundary mask is bypassed 2) The segment start address isn't taken into account when checking segment boundary limit Fix these two issues by removing the bypass of the segment boundary check even if the mask is set to the default value, and taking into account the actual start address of the request when checking if a segment needs splitting. Cc: stable@vger.kernel.org # v5.1+ Reviewed-by: Chris Mason <clm@fb.com> Tested-by: Chris Mason <clm@fb.com> Fixes: dcebd755926b ("block: use bio_for_each_bvec() to compute multi-page bvec count") Signed-off-by: Ming Lei <ming.lei@redhat.com> Dropped const on the page pointer, ppc page_to_phys() doesn't mark the page as const... Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-21Revert "block: split bio if the only bvec's length is > SZ_4K"Jens Axboe1-1/+1
We really don't need this, as the slow path will do the right thing anyway. This reverts commit 6952a7f8446ee85ea9d10ab87b64797a031eaae3. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08block: split bio if the only bvec's length is > SZ_4KMing Lei1-1/+1
64K PAGE_SIZE is popular on ARM64 or other ARCHs, and 64K has been big enough to break some devices probably, so change the logic to split bio if the only bvec's length is > SZ_4K instead of PAGE_SIZE. Fixes: fa5322872187 (block: avoid blk_bio_segment_split for small I/O operations) Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-08block: still try to split bio if the bvec crosses pagesMing Lei1-1/+2
Some device may set segment boundary as PAGE_SIZE - 1. If the bvec crosses pages, and meantime its length is <= PAGE_SIZE, we still need to split the bvec into 2 segments. Fixes this issue by still splitting bio if the single bvec crosses pages. Reported-by: kernel test robot <lkp@intel.com> Fixes: fa5322872187 (block: avoid blk_bio_segment_split for small I/O operations) Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-04block: avoid blk_bio_segment_split for small I/O operationsChristoph Hellwig1-1/+15
__blk_queue_split() adds significant overhead for small I/O operations. Add a shortcut to avoid it for cases where we know we never need to split. Based on a patch from Ming Lei. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-08-04block: Improve physical block alignment of split biosBart Van Assche1-4/+17
Consider the following example: * The logical block size is 4 KB. * The physical block size is 8 KB. * max_sectors equals (16 KB >> 9) sectors. * A non-aligned 4 KB and an aligned 64 KB bio are merged into a single non-aligned 68 KB bio. The current behavior is to split such a bio into (16 KB + 16 KB + 16 KB + 16 KB + 4 KB). The start of none of these five bio's is aligned to a physical block boundary. This patch ensures that such a bio is split into four aligned and one non-aligned bio instead of being split into five non-aligned bios. This improves performance because most block devices can handle aligned requests faster than non-aligned requests. Since the physical block size is larger than or equal to the logical block size, this patch preserves the guarantee that the returned value is a multiple of the logical block size. Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-08-04block: Simplify blk_bio_segment_split()Bart Van Assche1-35/+33
Move the max_sectors check into bvec_split_segs() such that a single call to that function can do all the necessary checks. This patch optimizes the fast path further, namely if a bvec fits in a page. Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-08-04block: Simplify bvec_split_segs()Bart Van Assche1-9/+7
Simplify this function by by removing two if-tests. Other than requiring that the @sectors pointer is not NULL, this patch does not change the behavior of bvec_split_segs(). Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-08-04block: Document the bio splitting functionsBart Van Assche1-0/+43
Since what the bio splitting functions do is nontrivial, document these functions. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-08-04block: Declare several function pointer arguments 'const'Bart Van Assche1-3/+4
Make it clear to the compiler and also to humans that the functions that query request queue properties do not modify any member of the request_queue data structure. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-07-03block: nr_phys_segments needs to be zero for REQ_OP_WRITE_ZEROESChristoph Hellwig1-1/+1
Fix a regression introduced when removing bi_phys_segments for Write Zeroes requests, which need to have a segment count of zero, as they don't have a payload. Fixes: 14ccb66b3f58 ("block: remove the bi_phys_segments field in struct bio") Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: untangle the end of blk_bio_segment_splitChristoph Hellwig1-11/+3
Now that we don't need to assign the front/back segment sizes, we can duplicating the segs assignment for the split vs no-split case and remove a whole chunk of boilerplate code. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: simplify blk_recalc_rq_segmentsChristoph Hellwig1-15/+6
Return the segement and let the callers assign them, which makes the code a littler more obvious. Also pass the request instead of q plus bio chain, allowing for the use of rq_for_each_bvec. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: remove the bi_phys_segments field in struct bioChristoph Hellwig1-48/+27
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 <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-23block: remove the bi_seg_{front,back}_size fields in struct bioChristoph Hellwig1-82/+12
At this point these fields aren't used for anything, so we can remove them. Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-23block: remove the segment size check in bio_will_gapChristoph Hellwig1-18/+1
We fundamentally do not have a maximum segement size for devices with a virt boundary. So don't bother checking it, especially given that the existing checks didn't properly work to start with as we never fully update the front/back segment size and miss the bi_seg_front_size that wuld have been required for some cases. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-23block: don't decrement nr_phys_segments for physically contigous segmentsChristoph Hellwig1-22/+1
Currently ll_merge_requests_fn, unlike all other merge functions, reduces nr_phys_segments by one if the last segment of the previous, and the first segment of the next segement are contigous. While this seems like a nice solution to avoid building smaller than possible requests it causes a mismatch between the segments actually present in the request and those iterated over by the bvec iterators, including __rq_for_each_bio. This can for example mistrigger the single segment optimization in the nvme-pci driver, and might lead to mismatching nr_phys_segments number when recalculating the number of request when inserting a cloned request. We could possibly work around this by making the bvec iterators take the front and back segment size into account, but that would require moving them from the bio to the bio_iter and spreading this mess over all users of bvecs. Or we could simply remove this optimization under the assumption that most users already build good enough bvecs, and that the bio merge patch never cared about this optimization either. The latter is what this patch does. dff824b2aadb ("nvme-pci: optimize mapping of small single segment requests"). Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-22block: avoid scatterlist offsets > PAGE_SIZEChristoph Hellwig1-1/+13
While we generally allow scatterlists to have offsets larger than page size for an entry, and other subsystems like the crypto code make use of that, the block layer isn't quite ready for that. Flip the switch back to avoid them for now, and revisit that decision early in a merge window once the known offenders are fixed. Fixes: 8a96a0e40810 ("block: rewrite blk_bvec_map_sg to avoid a nth_page call") Reviewed-by: Ming Lei <ming.lei@redhat.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-12block: rewrite blk_bvec_map_sg to avoid a nth_page callChristoph Hellwig1-15/+6
The offset in scatterlists is allowed to be larger than the page size, so don't go to great length to avoid that case and simplify the arithmetics. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-08block: fix build warning in merging bvecsMing Lei1-6/+10
Commit f6970f83ef79 ("block: don't check if adjacent bvecs in one bio can be mergeable") changes bvec merge by only considering two bvecs from different bios. However, if the former bio doesn't inlcude any io bvec, then the following warning may be triggered: warning: ‘bvec.bv_offset’ may be used uninitialized in this function [-Wmaybe-uninitialized] In practice, it shouldn't be triggered. Fixes it by adding check on former bio, the check shouldn't add any cost given 'bio->bi_iter' can be hit in cache. Reported-by: Jens Axboe <axboe@kernel.dk> Fixes: f6970f83ef79 ("block: don't check if adjacent bvecs in one bio can be mergeable") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-01block: don't check if adjacent bvecs in one bio can be mergeableMing Lei1-27/+42
Now both passthrough and FS IO have supported multi-page bvec, and bvec merging has been handled actually when adding page to bio, then adjacent bvecs won't be mergeable any more if they belong to same bio. So only try to merge bvecs if they are from different bios. Cc: Omar Sandoval <osandov@fb.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-01block: reuse __blk_bvec_map_sg() for mapping page sized bvecMing Lei1-11/+9
Inside __blk_segment_map_sg(), page sized bvec mapping is optimized a bit with one standalone branch. So reuse __blk_bvec_map_sg() to do that. Cc: Omar Sandoval <osandov@fb.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-01block: remove argument of 'request_queue' from __blk_bvec_map_sgMing Lei1-3/+3
The argument of 'request_queue' isn't used by __blk_bvec_map_sg(), so remove it. Cc: Omar Sandoval <osandov@fb.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-01block: don't merge adjacent bvecs to one segment in bio blk_queue_splitMing Lei1-17/+0
For normal filesystem IO, each page is added via blk_add_page(), in which bvec(page) merge has been handled already, and basically not possible to merge two adjacent bvecs in one bio. So not try to merge two adjacent bvecs in blk_queue_split(). Cc: Omar Sandoval <osandov@fb.com> Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-03-06block: fix segment calculation for passthrough IOMing Lei1-7/+8
blk_recount_segments() can be called in bio_add_pc_page() for calculating how many segments this bio will has after one page is added to this bio. If the resulted segment number is beyond the queue limit, the added page will be removed. The try-and-fix policy requires blk_recount_segments(__blk_recalc_rq_segments) to not consider the segment number limit. Unfortunately bvec_split_segs() does check this limit, and causes small segment number returned to bio_add_pc_page(), then page still may be added to the bio even though segment number limit becomes broken. Fixes this issue by not considering segment number limit when calcualting bio's segment number. Fixes: dcebd755926b ("block: use bio_for_each_bvec() to compute multi-page bvec count") Cc: Christoph Hellwig <hch@lst.de> Cc: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-03-02block: fix updating bio's front segment sizeMing Lei1-0/+8
When the current bvec can be merged to the 1st segment, the bio's front segment size has to be updated. However, dcebd755926b doesn't consider that case, then bio's front segment size may not be correct. This patch fixes this issue. Cc: Christoph Hellwig <hch@lst.de> Cc: Omar Sandoval <osandov@fb.com> Fixes: dcebd755926b ("block: use bio_for_each_bvec() to compute multi-page bvec count") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-27block: optimize blk_bio_segment_split for single-page bvecMing Lei1-3/+9
Introduce a fast path for single-page bvec IO, then we can avoid to call bvec_split_segs() unnecessarily. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-27block: optimize __blk_segment_map_sg() for single-page bvecMing Lei1-2/+7
Introduce a fast path for single-page bvec IO, then blk_bvec_map_sg() can be avoided. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-27block: introduce bvec_nth_page()Ming Lei1-1/+1
Single-page bvec can often be seen in small BS workloads, so introduce bvec_nth_page() for avoiding to call nth_page() unnecessarily, which looks not cheap. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-19block: avoid to READ fields of null bioMing Lei1-1/+3
rq->bio can be NULL sometimes, such as flush request, so don't read bio->bi_seg_front_size until this 'bio' is checked as valid. Cc: Bart Van Assche <bvanassche@acm.org> Reported-by: Bart Van Assche <bvanassche@acm.org> Fixes: dcebd755926b0f39dd1e ("block: use bio_for_each_bvec() to compute multi-page bvec count") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15block: kill QUEUE_FLAG_NO_SG_MERGEMing Lei1-25/+6
Since bdced438acd83ad83a6c ("block: setup bi_phys_segments after splitting"), physical segment number is mainly figured out in blk_queue_split() for fast path, and the flag of BIO_SEG_VALID is set there too. Now only blk_recount_segments() and blk_recalc_rq_segments() use this flag. Basically blk_recount_segments() is bypassed in fast path given BIO_SEG_VALID is set in blk_queue_split(). For another user of blk_recalc_rq_segments(): - run in partial completion branch of blk_update_request, which is an unusual case - run in blk_cloned_rq_check_limits(), still not a big problem if the flag is killed since dm-rq is the only user. Multi-page bvec is enabled now, not doing S/G merging is rather pointless with the current setup of the I/O path, as it isn't going to save you a significant amount of cycles. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15block: use bio_for_each_bvec() to map sgMing Lei1-20/+50
It is more efficient to use bio_for_each_bvec() to map sg, meantime we have to consider splitting multipage bvec as done in blk_bio_segment_split(). Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15block: use bio_for_each_bvec() to compute multi-page bvec countMing Lei1-20/+83
First it is more efficient to use bio_for_each_bvec() in both blk_bio_segment_split() and __blk_recalc_rq_segments() to compute how many multi-page bvecs there are in the bio. Secondly once bio_for_each_bvec() is used, the bvec may need to be splitted because its length can be very longer than max segment size, so we have to split the big bvec into several segments. Thirdly when splitting multi-page bvec into segments, the max segment limit may be reached, so the bio split need to be considered under this situation too. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15block: don't use bio->bi_vcnt to figure out segment numberMing Lei1-7/+1
It is wrong to use bio->bi_vcnt to figure out how many segments there are in the bio even though CLONED flag isn't set on this bio, because this bio may be splitted or advanced. So always use bio_segments() in blk_recount_segments(), and it shouldn't cause any performance loss now because the physical segment number is figured out in blk_queue_split() and BIO_SEG_VALID is set meantime since bdced438acd83ad83a6c ("block: setup bi_phys_segments after splitting"). Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Fixes: 76d8137a3113 ("blk-merge: recaculate segment if it isn't less than max segments") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-01-27Revert "block: cover another queue enter recursion via BIO_QUEUE_ENTERED"Jens Axboe1-0/+10
We can't touch a bio after ->make_request_fn(), for all we know it could already have been completed by the time this function returns. This reverts commit 698cef173983b086977e633e46476e0f925ca01e. Reported-by: syzbot+4df6ca820108fd248943@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-01-22block: cover another queue enter recursion via BIO_QUEUE_ENTEREDMing Lei1-10/+0
Except for blk_queue_split(), bio_split() is used for splitting bio too, then the remained bio is often resubmit to queue via generic_make_request(). So the same queue enter recursion exits in this case too. Unfortunatley commit cd4a4ae4683dc2 doesn't help this case. This patch covers the above case by setting BIO_QUEUE_ENTERED before calling q->make_request_fn. In theory the per-bio flag is used to simulate one stack variable, it is just fine to clear it after q->make_request_fn is returned. Especially the same bio can't be submitted from another context. Fixes: cd4a4ae4683dc2 ("block: don't use blocking queue entered for recursive bio submits") Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: NeilBrown <neilb@suse.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-28Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds1-11/+7
Pull SCSI updates from James Bottomley: "This is mostly update of the usual drivers: smarpqi, lpfc, qedi, megaraid_sas, libsas, zfcp, mpt3sas, hisi_sas. Additionally, we have a pile of annotation, unused variable and minor updates. The big API change is the updates for Christoph's DMA rework which include removing the DISABLE_CLUSTERING flag. And finally there are a couple of target tree updates" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (259 commits) scsi: isci: request: mark expected switch fall-through scsi: isci: remote_node_context: mark expected switch fall-throughs scsi: isci: remote_device: Mark expected switch fall-throughs scsi: isci: phy: Mark expected switch fall-through scsi: iscsi: Capture iscsi debug messages using tracepoints scsi: myrb: Mark expected switch fall-throughs scsi: megaraid: fix out-of-bound array accesses scsi: mpt3sas: mpt3sas_scsih: Mark expected switch fall-through scsi: fcoe: remove set but not used variable 'port' scsi: smartpqi: call pqi_free_interrupts() in pqi_shutdown() scsi: smartpqi: fix build warnings scsi: smartpqi: update driver version scsi: smartpqi: add ofa support scsi: smartpqi: increase fw status register read timeout scsi: smartpqi: bump driver version scsi: smartpqi: add smp_utils support scsi: smartpqi: correct lun reset issues scsi: smartpqi: correct volume status scsi: smartpqi: do not offline disks for transient did no connect conditions scsi: smartpqi: allow for larger raid maps ...
2018-12-18scsi: block: remove the cluster flagChristoph Hellwig1-11/+7
Now that the the SCSI layer replaced the use of the cluster flag with segment size limits and the DMA boundary we can remove the cluster flag from the block layer. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-12-14block: remove the blk_recount_segments exportChristoph Hellwig1-1/+0
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-10block: delete part_round_stats and switch to less precise countingMikulas Patocka1-1/+0
We want to convert to per-cpu in_flight counters. The function part_round_stats needs the in_flight counter every jiffy, it would be too costly to sum all the percpu variables every jiffy, so it must be deleted. part_round_stats is used to calculate two counters - time_in_queue and io_ticks. time_in_queue can be calculated without part_round_stats, by adding the duration of the I/O when the I/O ends (the value is almost as exact as the previously calculated value, except that time for in-progress I/Os is not counted). io_ticks can be approximated by increasing the value when I/O is started or ended and the jiffies value has changed. If the I/Os take less than a jiffy, the value is as exact as the previously calculated value. If the I/Os take more than a jiffy, io_ticks can drift behind the previously calculated value. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>