- 21 Jun, 2017 10 commits
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Bart Van Assche authored
Instead of documenting the locking assumptions of most block layer functions as a comment, use lockdep_assert_held() to verify locking assumptions at runtime. Signed-off-by:
Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by:
Jens Axboe <axboe@kernel.dk>
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Bart Van Assche authored
Add a comment above the queue_lockdep_assert_held() macro that explains the purpose of the q->queue_lock test. Signed-off-by:
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Bart Van Assche authored
Initialization of blk-mq requests is a bit weird: blk_mq_rq_ctx_init() is called after a value has been assigned to .rq_flags and .rq_flags is initialized in __blk_mq_finish_request(). Initialize .rq_flags in blk_mq_rq_ctx_init() instead of relying on __blk_mq_finish_request(). Moving the initialization of .rq_flags is fine because all changes and tests of .rq_flags occur between blk_get_request() and finishing a request. Signed-off-by:
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Bart Van Assche authored
Since scsi_req_init() works on a struct scsi_request, change the argument type into struct scsi_request *. Signed-off-by:
Hannes Reinecke <hare@suse.com> Reviewed-by:
Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
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Bart Van Assche authored
Instead of explicitly calling scsi_req_init() after blk_get_request(), call that function from inside blk_get_request(). Add an .initialize_rq_fn() callback function to the block drivers that need it. Merge the IDE .init_rq_fn() function into .initialize_rq_fn() because it is too small to keep it as a separate function. Keep the scsi_req_init() call in ide_prep_sense() because it follows a blk_rq_init() call. References: commit 82ed4db4 ("block: split scsi_request out of struct request") Signed-off-by:
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Bart Van Assche authored
Several block drivers need to initialize the driver-private request data after having called blk_get_request() and before .prep_rq_fn() is called, e.g. when submitting a REQ_OP_SCSI_* request. Avoid that that initialization code has to be repeated after every blk_get_request() call by adding new callback functions to struct request_queue and to struct blk_mq_ops. Signed-off-by:
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Bart Van Assche authored
Instead of declaring the second argument of blk_*_get_request() as int and passing it to functions that expect an unsigned int, declare that second argument as unsigned int. Also because of consistency, rename that second argument from 'rw' into 'op'. This patch does not change any functionality. Signed-off-by:
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Bart Van Assche authored
Since the srcu structure is rather large (184 bytes on an x86-64 system with kernel debugging disabled), only allocate it if needed. Reported-by:
Ming Lei <ming.lei@redhat.com> Signed-off-by:
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Christoph Hellwig authored
While the Write Same page currently always is in low-level it is just as easy and safer to just compare the page and offset directly. Signed-off-by:
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Christoph Hellwig authored
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- 20 Jun, 2017 11 commits
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Jens Axboe authored
Some storage drivers need to share tag sets between devices. It's useful to be able to model that with null_blk, to find hangs or performance issues. Add a 'shared_tags' bool module parameter that. If that is set to true and nr_devices is bigger than 1, all devices allocated will share the same tag set. Signed-off-by: -
Goldwyn Rodrigues authored
Return EAGAIN if any of the following checks fail + i_rwsem is not lockable + NODATACOW or PREALLOC is not set + Cannot nocow at the desired location + Writing beyond end of file which is not allocated Acked-by:
David Sterba <dsterba@suse.com> Signed-off-by:
Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by:
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Goldwyn Rodrigues authored
If IOCB_NOWAIT is set, bail if the i_rwsem is not lockable immediately. IF IOMAP_NOWAIT is set, return EAGAIN in xfs_file_iomap_begin if it needs allocation either due to file extension, writing to a hole, or COW or waiting for other DIOs to finish. Return -EAGAIN if we don't have extent list in memory. Signed-off-by:
Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by:
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Goldwyn Rodrigues authored
Return EAGAIN if any of the following checks fail for direct I/O: + i_rwsem is lockable + Writing beyond end of file (will trigger allocation) + Blocks are not allocated at the write location Signed-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
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Goldwyn Rodrigues authored
A new bio operation flag REQ_NOWAIT is introduced to identify bio's orignating from iocb with IOCB_NOWAIT. This flag indicates to return immediately if a request cannot be made instead of retrying. Stacked devices such as md (the ones with make_request_fn hooks) currently are not supported because it may block for housekeeping. For example, an md can have a part of the device suspended. For this reason, only request based devices are supported. In the future, this feature will be expanded to stacked devices by teaching them how to handle the REQ_NOWAIT flags. Reviewed-by:
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Goldwyn Rodrigues authored
IOCB_NOWAIT translates to IOMAP_NOWAIT for iomaps. This is used by XFS in the XFS patch. Reviewed-by:
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Goldwyn Rodrigues authored
Find out if the I/O will trigger a wait due to writeback. If yes, return -EAGAIN. Return -EINVAL for buffered AIO: there are multiple causes of delay such as page locks, dirty throttling logic, page loading from disk etc. which cannot be taken care of. Reviewed-by:
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Goldwyn Rodrigues authored
RWF_NOWAIT informs kernel to bail out if an AIO request will block for reasons such as file allocations, or a writeback triggered, or would block while allocating requests while performing direct I/O. RWF_NOWAIT is translated to IOCB_NOWAIT for iocb->ki_flags. FMODE_AIO_NOWAIT is a flag which identifies the file opened is capable of returning -EAGAIN if the AIO call will block. This must be set by supporting filesystems in the ->open() call. Filesystems xfs, btrfs and ext4 would be supported in the following patches. Reviewed-by:
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Goldwyn Rodrigues authored
aio_rw_flags is introduced in struct iocb (using aio_reserved1) which will carry the RWF_* flags. We cannot use aio_flags because they are not checked for validity which may break existing applications. Note, the only place RWF_HIPRI comes in effect is dio_await_one(). All the rest of the locations, aio code return -EIOCBQUEUED before the checks for RWF_HIPRI. Reviewed-by:
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Goldwyn Rodrigues authored
filemap_range_has_page() return true if the file's mapping has a page within the range mentioned. This function will be used to check if a write() call will cause a writeback of previous writes. Reviewed-by:
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Goldwyn Rodrigues authored
Also added RWF_SUPPORTED to encompass all flags. Reviewed-by:
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- 19 Jun, 2017 1 commit
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Ming Lei authored
When nvme_kill_queues() is run, queues may be in quiesced state, so we forcibly unquiesce queues to avoid blocking dispatch, and I/O hang can be avoided in remove path. Peviously we use blk_mq_start_stopped_hw_queues() as counterpart of blk_mq_quiesce_queue(), now we have introduced blk_mq_unquiesce_queue(), so use it explicitly. Cc: linux-nvme@lists.infradead.org Signed-off-by:
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- 18 Jun, 2017 18 commits
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Ming Lei authored
This patch reverts commit 2719aa21(blk-mq: don't use sync workqueue flushing from drivers) because only blk_mq_quiesce_queue() need the sync flush, and now we don't need to stop queue any more, so revert it. Also changes to cancel_delayed_work() in blk_mq_stop_hw_queue(). Reviewed-by:
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Ming Lei authored
BLK_MQ_S_STOPPED may not be observed in other concurrent I/O paths, we can't guarantee that dispatching won't happen after returning from the APIs of stopping queue. So clarify the fact and avoid potential misuse. Signed-off-by:
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Ming Lei authored
Queue can be started by other blk-mq APIs and can be used in different cases, this limits uses of blk_mq_quiesce_queue() if it is based on stopping queue, and make its usage very difficult, especially users have to use the stop queue APIs carefully for avoiding to break blk_mq_quiesce_queue(). We have applied the QUIESCED flag for draining and blocking dispatch, so it isn't necessary to stop queue any more. After stopping queue is removed, blk_mq_quiesce_queue() can be used safely and easily, then users won't worry about queue restarting during quiescing at all. Reviewed-by:
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Ming Lei authored
Actually what we want to get from blk_mq_quiesce_queue() isn't only to wait for completion of all ongoing .queue_rq(). In the typical context of canceling requests, we need to make sure that the following is done in the dispatch path before starting to cancel requests: - failed dispatched request is finished - busy dispatched request is requeued, and the STARTED flag is cleared So update comment to keep code, doc and our expection consistent. Signed-off-by:
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Ming Lei authored
It is required that no dispatch can happen any more once blk_mq_quiesce_queue() returns, and we don't have such requirement on APIs of stopping queue. But blk_mq_quiesce_queue() still may not block/drain dispatch in the the case of BLK_MQ_S_START_ON_RUN, so use the new introduced flag of QUEUE_FLAG_QUIESCED and evaluate it inside RCU read-side critical sections for fixing this issue. Also blk_mq_quiesce_queue() is implemented via stopping queue, which limits its uses, and easy to cause race, because any queue restart in other paths may break blk_mq_quiesce_queue(). With the introduced flag of QUEUE_FLAG_QUIESCED, we don't need to depend on stopping queue for quiescing any more. Signed-off-by:
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Ming Lei authored
blk_mq_unquiesce_queue() is used for unquiescing the queue explicitly, so replace blk_mq_start_stopped_hw_queues() with it. For the scsi part, this patch takes Bart's suggestion to switch to block quiesce/unquiesce API completely. Cc: linux-nvme@lists.infradead.org Cc: linux-scsi@vger.kernel.org Cc: dm-devel@redhat.com Reviewed-by:
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Ming Lei authored
blk_mq_start_stopped_hw_queues() is used implictly as counterpart of blk_mq_quiesce_queue() for unquiescing queue, so we introduce blk_mq_unquiesce_queue() and make it as counterpart of blk_mq_quiesce_queue() explicitly. This function is for improving the current quiescing mechanism in the following patches. Reviewed-by:
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Ming Lei authored
This patch introduces blk_mq_quiesce_queue_nowait() so that we can workaround mpt3sas for quiescing its queue. Once mpt3sas is fixed, we can remove this helper. Reviewed-by:
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Ming Lei authored
We usually put blk_mq_*() into include/linux/blk-mq.h, so move this API into there. Signed-off-by:
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NeilBrown authored
blk_bio_segment_split() makes sure bios have no more than BIO_MAX_PAGES entries in the bi_io_vec. This was done because bio_clone_bioset() (when given a mempool bioset) could not handle larger io_vecs. No driver uses bio_clone_bioset() any more, they all use bio_clone_fast() if anything, and bio_clone_fast() doesn't clone the bi_io_vec. The main user of of bio_clone_bioset() at this level is bounce.c, and bouncing now happens before blk_bio_segment_split(), so that is not of concern. So remove the big helpful comment and the code. Reviewed-by:
NeilBrown <neilb@suse.com> Signed-off-by:
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NeilBrown authored
bio_clone() is no longer used. Only bio_clone_bioset() or bio_clone_fast(). This is for the best, as bio_clone() used fs_bio_set, and filesystems are unlikely to want to use bio_clone(). So remove bio_clone() and all references. This includes a fix to some incorrect documentation. Reviewed-by:
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NeilBrown authored
This function allocates a bio, then a collection of pages. It copes with failure. It currently uses a mempool() to allocate the bio, but alloc_page() to allocate the pages. These fail in different ways, so the usage is inconsistent. Change the bio_clone() to bio_clone_kmalloc() so that no pool is used either for the bio or the pages. Reviewed-by:
Kent Overstreet <kent.overstreet@gmail.com> Reviewed-by : Ming Lei <ming.lei@redhat.com> Signed-off-by:
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NeilBrown authored
bios that are re-submitted will pass through blk_queue_split() when blk_queue_bio() is called, and this will split the bio if necessary. There is no longer any need to do this splitting in xen-blkfront. Acked-by:
Roger Pau Monné <roger.pau@citrix.com> Reviewed-by:
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NeilBrown authored
pblk_submit_read() uses bio_clone_bioset() but doesn't change the io_vec, so bio_clone_fast() is a better choice. It also uses fs_bio_set which is intended for filesystems. Using it in a device driver can deadlock. So allocate a new bioset, and and use bio_clone_fast(). Reviewed-by:
Javier González <javier@cnexlabs.com> Tested-by:
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NeilBrown authored
pktcdvd doesn't change the bi_io_vec of the clone bio, so it is more efficient to use bio_clone_fast(), and not clone the bi_io_vec. This requires providing a bio_set, and it is safest to provide a dedicated bio_set rather than sharing fs_bio_set, which filesytems use. This new bio_set, pkt_bio_set, can also be use for the bio_split() call as the two allocations (bio_clone_fast, and bio_split) are independent, neither can block a bio allocated by the other. Reviewed-by:
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NeilBrown authored
drbd does not modify the bi_io_vec of the cloned bio, so there is no need to clone that part. So bio_clone_fast() is the better choice. For bio_clone_fast() we need to specify a bio_set. We could use fs_bio_set, which bio_clone() uses, or drbd_md_io_bio_set, which drbd uses for metadata, but it is generally best to avoid sharing bio_sets unless you can be certain that there are no interdependencies. So create a new bio_set, drbd_io_bio_set, and use bio_clone_fast(). Also remove a "XXX cannot fail ???" comment because it definitely cannot fail - bio_clone_fast() doesn't fail if the GFP flags allow for sleeping. Reviewed-by:
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NeilBrown authored
bio_clone() makes a copy of the bi_io_vec, but rbd never changes that, so there is no need for a copy. bio_clone_fast() can be used instead, which avoids making the copy. This requires that we provide a bio_set. bio_clone() uses fs_bio_set, but it isn't, in general, safe to use the same bio_set at different levels of the stack, as that can lead to deadlocks. As filesystems use fs_bio_set, block devices shouldn't. As rbd never stacks, it is safe to have a single global bio_set for all rbd devices to use. So allocate that when the module is initialised, and use it with bio_clone_fast(). Reviewed-by:
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NeilBrown authored
Since commit 23688bf4 ("block: ensure to split after potentially bouncing a bio") blk_queue_bounce() is called *before* blk_queue_split(). This means that: 1/ the comments blk_queue_split() about bounce buffers are irrelevant, and 2/ a very large bio (more than BIO_MAX_PAGES) will no longer be split before it arrives at blk_queue_bounce(), leading to the possibility that bio_clone_bioset() will fail and a NULL will be dereferenced. Separately, blk_queue_bounce() shouldn't use fs_bio_set as the bio being copied could be from the same set, and this could lead to a deadlock. So: - allocate 2 private biosets for blk_queue_bounce, one for splitting enormous bios and one for cloning bios. - add code to split a bio that exceeds BIO_MAX_PAGES. - Fix up the comments in blk_queue_split() Credit-to: Ming Lei <tom.leiming@gmail.com> (suggested using single bio_for_each_segment loop) Reviewed-by:
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