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2015-07-23block: Do a full clone when splitting discard biosMartin K. Petersen
This fixes a data corruption bug when using discard on top of MD linear, raid0 and raid10 personalities. Commit 20d0189b1012 "block: Introduce new bio_split()" permits sharing the bio_vec between the two resulting bios. That is fine for read/write requests where the bio_vec is immutable. For discards, however, we need to be able to attach a payload and update the bio_vec so the page can get mapped to a scatterlist entry. Therefore the bio_vec can not be shared when splitting discards and we must do a full clone. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reported-by: Seunguk Shin <seunguk.shin@samsung.com> Tested-by: Seunguk Shin <seunguk.shin@samsung.com> Cc: Seunguk Shin <seunguk.shin@samsung.com> Cc: Jens Axboe <axboe@fb.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: <stable@vger.kernel.org> # v3.14+ Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-23block: export bio_associate_*() and wbc_account_io()Tejun Heo
bio_associate_blkcg(), bio_associate_current() and wbc_account_io() are used to implement cgroup writeback support for filesystems and thus need to be exported. Export them. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-06-02blkcg: implement bio_associate_blkcg()Tejun Heo
Currently, a bio can only be associated with the io_context and blkcg of %current using bio_associate_current(). This is too restrictive for cgroup writeback support. Implement bio_associate_blkcg() which associates a bio with the specified blkcg. bio_associate_blkcg() leaves the io_context unassociated. bio_associate_current() is updated so that it considers a bio as already associated if it has a blkcg_css, instead of an io_context, associated with it. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-06-02cgroup, block: implement task_get_css() and use it in bio_associate_current()Tejun Heo
bio_associate_current() currently open codes task_css() and css_tryget_online() to find and pin $current's blkcg css. Abstract it into task_get_css() which is implemented from cgroup side. As a task is always associated with an online css for every subsystem except while the css_set update is propagating, task_get_css() retries till css_tryget_online() succeeds. This is a cleanup and shouldn't lead to noticeable behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-22block: remove management of bi_remaining when restoring original bi_end_ioMike Snitzer
Commit c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains") regressed all existing callers that followed this pattern: 1) saving a bio's original bi_end_io 2) wiring up an intermediate bi_end_io 3) restoring the original bi_end_io from intermediate bi_end_io 4) calling bio_endio() to execute the restored original bi_end_io The regression was due to BIO_CHAIN only ever getting set if bio_inc_remaining() is called. For the above pattern it isn't set until step 3 above (step 2 would've needed to establish BIO_CHAIN). As such the first bio_endio(), in step 2 above, never decremented __bi_remaining before calling the intermediate bi_end_io -- leaving __bi_remaining with the value 1 instead of 0. When bio_inc_remaining() occurred during step 3 it brought it to a value of 2. When the second bio_endio() was called, in step 4 above, it should've called the original bi_end_io but it didn't because there was an extra reference that wasn't dropped (due to atomic operations being optimized away since BIO_CHAIN wasn't set upfront). Fix this issue by removing the __bi_remaining management complexity for all callers that use the above pattern -- bio_chain() is the only interface that _needs_ to be concerned with __bi_remaining. For the above pattern callers just expect the bi_end_io they set to get called! Remove bio_endio_nodec() and also remove all bio_inc_remaining() calls that aren't associated with the bio_chain() interface. Also, the bio_inc_remaining() interface has been moved local to bio.c. Fixes: c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains") Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-05bio: skip atomic inc/dec of ->bi_cnt for most use casesJens Axboe
Struct bio has a reference count that controls when it can be freed. Most uses cases is allocating the bio, which then returns with a single reference to it, doing IO, and then dropping that single reference. We can remove this atomic_dec_and_test() in the completion path, if nobody else is holding a reference to the bio. If someone does call bio_get() on the bio, then we flag the bio as now having valid count and that we must properly honor the reference count when it's being put. Tested-by: Robert Elliott <elliott@hp.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-05bio: skip atomic inc/dec of ->bi_remaining for non-chainsJens Axboe
Struct bio has an atomic ref count for chained bio's, and we use this to know when to end IO on the bio. However, most bio's are not chained, so we don't need to always introduce this atomic operation as part of ending IO. Add a helper to elevate the bi_remaining count, and flag the bio as now actually needing the decrement at end_io time. Rename the field to __bi_remaining to catch any current users of this doing the incrementing manually. For high IOPS workloads, this reduces the overhead of bio_endio() substantially. Tested-by: Robert Elliott <elliott@hp.com> Acked-by: Kent Overstreet <kent.overstreet@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: rewrite and split __bio_copy_iov()Dongsu Park
Rewrite __bio_copy_iov using the copy_page_{from,to}_iter helpers, and split it into two simpler functions. This commit should contain only literal replacements, without functional changes. Cc: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dongsu Park <dongsu.park@profitbricks.com> [hch: removed the __bio_copy_iov wrapper] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: merge __bio_map_user_iov into bio_map_user_iovChristoph Hellwig
And also remove the unused bdev argument. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: merge __bio_map_kern into bio_map_kernChristoph Hellwig
This saves a little code, and allow to simplify the error handling. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: pass iov_iter to the BLOCK_PC mapping functionsKent Overstreet
Make use of a new interface provided by iov_iter, backed by scatter-gather list of iovec, instead of the old interface based on sg_iovec. Also use iov_iter_advance() instead of manual iteration. This commit should contain only literal replacements, without functional changes. Cc: Christoph Hellwig <hch@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Doug Gilbert <dgilbert@interlog.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Signed-off-by: Kent Overstreet <kmo@daterainc.com> [dpark: add more description in commit message] Signed-off-by: Dongsu Park <dongsu.park@profitbricks.com> [hch: fixed to do a deep clone of the iov_iter, and to properly use the iov_iter direction] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: add a helper to free bio bounce buffer pagesChristoph Hellwig
The code sniplet to walk all bio_vecs and free their pages is opencoded in way to many places, so factor it into a helper. Also convert the slightly more complex cases in bio_kern_endio and __bio_copy_iov where we break the freeing from an existing loop into a separate one. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: use blk_rq_map_user_iov to implement blk_rq_map_userChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: simplify bio_map_kernChristoph Hellwig
Just open code the trivial mapping from a kernel virtual address to a bio instead of going through the complex user address mapping machinery. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-11bio: modify __bio_add_page() to accept pages that don't start a new segmentMaurizio Lombardi
The original behaviour is to refuse to add a new page if the maximum number of segments has been reached, regardless of the fact the page we are going to add can be merged into the last segment or not. Unfortunately, when the system runs under heavy memory fragmentation conditions, a driver may try to add multiple pages to the last segment. The original code won't accept them and EBUSY will be reported to userspace. This patch modifies the function so it refuses to add a page only in case the latter starts a new segment and the maximum number of segments has already been reached. The bug can be easily reproduced with the st driver: 1) set CONFIG_SCSI_MPT2SAS_MAX_SGE or CONFIG_SCSI_MPT3SAS_MAX_SGE to 16 2) modprobe st buffer_kbs=1024 3) #dd if=/dev/zero of=/dev/st0 bs=1M count=10 dd: error writing `/dev/st0': Device or resource busy Signed-off-by: Maurizio Lombardi <mlombard@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Cc: Jet Chen <jet.chen@intel.com> Cc: Tomas Henzl <thenzl@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-11-24blk: introduce generic io stat accounting help functionGu Zheng
Many block drivers accounting io stat based on bio (e.g. NVMe...), the blk_account_io_start/end() which is based on request does not make sense to them, so here we introduce the similar help function named generic_start/end_io_acct base on raw sectors, and it can simplify some driver's open io accounting code. Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-10-03block: add bioset_create_nobvec()Junichi Nomura
Users of bio_clone_fast() do not want bios with their own bvecs. Allocating a bvec mempool as part of the bioset intended for such users is a waste of memory. bioset_create_nobvec() creates a bioset that doesn't have the bvec mempool. Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-08-01block: use kmalloc alignment for bio slabMikulas Patocka
Various subsystems can ask the bio subsystem to create a bio slab cache with some free space before the bio. This free space can be used for any purpose. Device mapper uses this per-bio-data feature to place some target-specific and device-mapper specific data before the bio, so that the target-specific data doesn't have to be allocated separately. This per-bio-data mechanism is used in place of kmalloc, so we need the allocated slab to have the same memory alignment as memory allocated with kmalloc. Change bio_find_or_create_slab() so that it uses ARCH_KMALLOC_MINALIGN alignment when creating the slab cache. This is needed so that dm-crypt can use per-bio-data for encryption - the crypto subsystem assumes this data will have the same alignment as kmalloc'ed memory. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Jens Axboe <axboe@fb.com>
2014-06-24block: add support for limiting gaps in SG listsJens Axboe
Another restriction inherited for NVMe - those devices don't support SG lists that have "gaps" in them. Gaps refers to cases where the previous SG entry doesn't end on a page boundary. For NVMe, all SG entries must start at offset 0 (except the first) and end on a page boundary (except the last). Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-11Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block layer fixes from Jens Axboe: "Final small batch of fixes to be included before -rc1. Some general cleanups in here as well, but some of the blk-mq fixes we need for the NVMe conversion and/or scsi-mq. The pull request contains: - Support for not merging across a specified "chunk size", if set by the driver. Some NVMe devices perform poorly for IO that crosses such a chunk, so we need to support it generically as part of request merging avoid having to do complicated split logic. From me. - Bump max tag depth to 10Ki tags. Some scsi devices have a huge shared tag space. Before we failed with EINVAL if a too large tag depth was specified, now we truncate it and pass back the actual value. From me. - Various blk-mq rq init fixes from me and others. - A fix for enter on a dying queue for blk-mq from Keith. This is needed to prevent oopsing on hot device removal. - Fixup for blk-mq timer addition from Ming Lei. - Small round of performance fixes for mtip32xx from Sam Bradshaw. - Minor stack leak fix from Rickard Strandqvist. - Two __init annotations from Fabian Frederick" * 'for-linus' of git://git.kernel.dk/linux-block: block: add __init to blkcg_policy_register block: add __init to elv_register block: ensure that bio_add_page() always accepts a page for an empty bio blk-mq: add timer in blk_mq_start_request blk-mq: always initialize request->start_time block: blk-exec.c: Cleaning up local variable address returnd mtip32xx: minor performance enhancements blk-mq: ->timeout should be cleared in blk_mq_rq_ctx_init() blk-mq: don't allow queue entering for a dying queue blk-mq: bump max tag depth to 10K tags block: add blk_rq_set_block_pc() block: add notion of a chunk size for request merging
2014-06-10block: ensure that bio_add_page() always accepts a page for an empty bioJens Axboe
With commit 762380ad9322 added support for chunk sizes and no merging across them, it broke the rule of always allowing adding of a single page to an empty bio. So relax the restriction a bit to allow for that, similarly to what we have always done. This fixes a crash with mkfs.xfs and 512b sector sizes on NVMe. Reported-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-09Merge branch 'for-3.16' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "A lot of activities on cgroup side. Heavy restructuring including locking simplification took place to improve the code base and enable implementation of the unified hierarchy, which currently exists behind a __DEVEL__ mount option. The core support is mostly complete but individual controllers need further work. To explain the design and rationales of the the unified hierarchy Documentation/cgroups/unified-hierarchy.txt is added. Another notable change is css (cgroup_subsys_state - what each controller uses to identify and interact with a cgroup) iteration update. This is part of continuing updates on css object lifetime and visibility. cgroup started with reference count draining on removal way back and is now reaching a point where csses behave and are iterated like normal refcnted objects albeit with some complexities to allow distinguishing the state where they're being deleted. The css iteration update isn't taken advantage of yet but is planned to be used to simplify memcg significantly" * 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (77 commits) cgroup: disallow disabled controllers on the default hierarchy cgroup: don't destroy the default root cgroup: disallow debug controller on the default hierarchy cgroup: clean up MAINTAINERS entries cgroup: implement css_tryget() device_cgroup: use css_has_online_children() instead of has_children() cgroup: convert cgroup_has_live_children() into css_has_online_children() cgroup: use CSS_ONLINE instead of CGRP_DEAD cgroup: iterate cgroup_subsys_states directly cgroup: introduce CSS_RELEASED and reduce css iteration fallback window cgroup: move cgroup->serial_nr into cgroup_subsys_state cgroup: link all cgroup_subsys_states in their sibling lists cgroup: move cgroup->sibling and ->children into cgroup_subsys_state cgroup: remove cgroup->parent device_cgroup: remove direct access to cgroup->children memcg: update memcg_has_children() to use css_next_child() memcg: remove tasks/children test from mem_cgroup_force_empty() cgroup: remove css_parent() cgroup: skip refcnting on normal root csses and cgrp_dfl_root self css cgroup: use cgroup->self.refcnt for cgroup refcnting ...
2014-06-05block: add notion of a chunk size for request mergingJens Axboe
Some drivers have different limits on what size a request should optimally be, depending on the offset of the request. Similar to dividing a device into chunks. Add a setting that allows the driver to inform the block layer of such a chunk size. The block layer will then prevent merging across the chunks. This is needed to optimally support NVMe with a non-zero stripe size. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-19block: move bio.c and bio-integrity.c from fs/ to block/Jens Axboe
They really belong in block/, especially now since it's not in drivers/block/ anymore. Additionally, the get_maintainer script gets it wrong when in fs/. Suggested-by: Christoph Hellwig <hch@infradead.org> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Jens Axboe <axboe@fb.com>