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2017-02-03block: free merged request in the callerJens Axboe5-12/+35
If we end up doing a request-to-request merge when we have completed a bio-to-request merge, we free the request from deep down in that path. For blk-mq-sched, the merge path has to hold the appropriate lock, but we don't need it for freeing the request. And in fact holding the lock is problematic, since we are now calling the mq sched put_rq_private() hook with the lock held. Other call paths do not hold this lock. Fix this inconsistency by ensuring that the caller frees a merged request. Then we can do it outside of the lock, making it both more efficient and fixing the blk-mq-sched problem of invoking parts of the scheduler with an unknown lock state. Reported-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com>
2017-02-03blk-merge: return the merged requestJens Axboe2-17/+18
When we attempt to merge request-to-request, we return a 0/1 if we ended up merging or not. Change that to return the pointer to the request that we freed. We will use this to move the freeing of that request out of the merge logic, so that callers can drop locks before freeing the request. There should be no functional changes in this patch. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com>
2017-02-03blkcg: fix double free of new_blkg in blkcg_init_queueHou Tao1-3/+1
If blkg_create fails, new_blkg passed as an argument will be freed by blkg_create, so there is no need to free it again. Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-03blk-mq-sched: bypass the scheduler for flushes entirelyOmar Sandoval3-6/+23
There's a weird inconsistency that flushes are mostly hidden from the scheduler, but it needs to be aware of them in ->insert_requests(). Instead of having every scheduler call blk_mq_sched_bypass_insert(), let's do it in the common framework. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02blk-mq: move debugfs_remove() of disk dir to blk_release_queue()Omar Sandoval2-1/+4
This needs to happen after we tear down blktrace. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02block: use same block debugfs directory for blk-mq and blktraceOmar Sandoval5-16/+16
When I added the blk-mq debugging information to debugfs, I didn't notice that blktrace also creates a "block" directory in debugfs. Make them use the same dentry, now created in the core block code. Based on a patch from Jens. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02scsi, block: fix duplicate bdi name registration crashesDan Williams2-0/+22
Warnings of the following form occur because scsi reuses a devt number while the block layer still has it referenced as the name of the bdi [1]: WARNING: CPU: 1 PID: 93 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x62/0x80 sysfs: cannot create duplicate filename '/devices/virtual/bdi/8:192' [..] Call Trace: dump_stack+0x86/0xc3 __warn+0xcb/0xf0 warn_slowpath_fmt+0x5f/0x80 ? kernfs_path_from_node+0x4f/0x60 sysfs_warn_dup+0x62/0x80 sysfs_create_dir_ns+0x77/0x90 kobject_add_internal+0xb2/0x350 kobject_add+0x75/0xd0 device_add+0x15a/0x650 device_create_groups_vargs+0xe0/0xf0 device_create_vargs+0x1c/0x20 bdi_register+0x90/0x240 ? lockdep_init_map+0x57/0x200 bdi_register_owner+0x36/0x60 device_add_disk+0x1bb/0x4e0 ? __pm_runtime_use_autosuspend+0x5c/0x70 sd_probe_async+0x10d/0x1c0 async_run_entry_fn+0x39/0x170 This is a brute-force fix to pass the devt release information from sd_probe() to the locations where we register the bdi, device_add_disk(), and unregister the bdi, blk_cleanup_queue(). Thanks to Omar for the quick reproducer script [2]. This patch survives where an unmodified kernel fails in a few seconds. [1]: https://marc.info/?l=linux-scsi&m=147116857810716&w=4 [2]: http://marc.info/?l=linux-block&m=148554717109098&w=2 Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: Bart Van Assche <bart.vanassche@sandisk.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Jan Kara <jack@suse.cz> Reported-by: Omar Sandoval <osandov@osandov.com> Tested-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02block: Get rid of blk_get_backing_dev_info()Jan Kara3-24/+4
blk_get_backing_dev_info() is now a simple dereference. Remove that function and simplify some code around that. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02block: Make blk_get_backing_dev_info() safe without open bdevJan Kara1-5/+3
Currenly blk_get_backing_dev_info() is not safe to be called when the block device is not open as bdev->bd_disk is NULL in that case. However inode_to_bdi() uses this function and may be call called from flusher worker or other writeback related functions without bdev being open which leads to crashes such as: [113031.075540] Unable to handle kernel paging request for data at address 0x00000000 [113031.075614] Faulting instruction address: 0xc0000000003692e0 0:mon> t [c0000000fb65f900] c00000000036cb6c writeback_sb_inodes+0x30c/0x590 [c0000000fb65fa10] c00000000036ced4 __writeback_inodes_wb+0xe4/0x150 [c0000000fb65fa70] c00000000036d33c wb_writeback+0x30c/0x450 [c0000000fb65fb40] c00000000036e198 wb_workfn+0x268/0x580 [c0000000fb65fc50] c0000000000f3470 process_one_work+0x1e0/0x590 [c0000000fb65fce0] c0000000000f38c8 worker_thread+0xa8/0x660 [c0000000fb65fd80] c0000000000fc4b0 kthread+0x110/0x130 [c0000000fb65fe30] c0000000000098f0 ret_from_kernel_thread+0x5c/0x6c Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02block: Dynamically allocate and refcount backing_dev_infoJan Kara2-8/+6
Instead of storing backing_dev_info inside struct request_queue, allocate it dynamically, reference count it, and free it when the last reference is dropped. Currently only request_queue holds the reference but in the following patch we add other users referencing backing_dev_info. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02block: Use pointer to backing_dev_info from request_queueJan Kara7-28/+29
We will want to have struct backing_dev_info allocated separately from struct request_queue. As the first step add pointer to backing_dev_info to request_queue and convert all users touching it. No functional changes in this patch. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02block: Unhash block device inodes on gendisk destructionJan Kara1-0/+2
Currently, block device inodes stay around after corresponding gendisk hash died until memory reclaim finds them and frees them. Since we will make block device inode pin the bdi, we want to free the block device inode as soon as the device goes away so that bdi does not stay around unnecessarily. Furthermore we need to avoid issues when new device with the same major,minor pair gets created since reusing the bdi structure would be rather difficult in this case. Unhashing block device inode on gendisk destruction nicely deals with these problems. Once last block device inode reference is dropped (which may be directly in del_gendisk()), the inode gets evicted. Furthermore if the major,minor pair gets reallocated, we are guaranteed to get new block device inode even if old block device inode is not yet evicted and thus we avoid issues with possible reuse of bdi. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-01blk-mq-debug: Introduce debugfs_create_files()Bart Van Assche1-17/+17
Replace the two debugfs_create_file() loops by a call to the new debugfs_create_files() function. Add an empty element at the end of the two attribute arrays such that the array size does not have to be passed to debugfs_create_files(). Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-01blk-mq-debug: Make show() operations interruptibleBart Van Assche1-8/+26
Allow users to interrupt show operations instead of making a user space process unkillable if ownership of q->sysfs_lock cannot be obtained. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-01blk-mq-debug: Avoid that sparse complains about req_flags_t usageBart Van Assche2-2/+2
Avoid that sparse reports the following complaints: block/elevator.c:541:29: warning: incorrect type in assignment (different base types) block/elevator.c:541:29: expected bool [unsigned] [usertype] next_sorted block/elevator.c:541:29: got restricted req_flags_t block/blk-mq-debugfs.c:92:54: warning: cast from restricted req_flags_t Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-01blk-mq-debugfs: Add missing __acquires() / __releases() annotationsBart Van Assche1-0/+4
This patch avoids that sparse complains about lock imbalances. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-01block: fold cmd_type into the REQ_OP_ spaceChristoph Hellwig7-36/+24
Instead of keeping two levels of indirection for requests types, fold it all into the operations. The little caveat here is that previously cmd_type only applied to struct request, while the request and bio op fields were set to plain REQ_OP_READ/WRITE even for passthrough operations. Instead this patch adds new REQ_OP_* for SCSI passthrough and driver private requests, althought it has to add two for each so that we can communicate the data in/out nature of the request. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-01block: introduce blk_rq_is_passthroughChristoph Hellwig5-9/+9
This can be used to check for fs vs non-fs requests and basically removes all knowledge of BLOCK_PC specific from the block layer, as well as preparing for removing the cmd_type field in struct request. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-31block: make scsi_request and scsi ioctl support optionalChristoph Hellwig2-2/+8
We only need this code to support scsi, ide, cciss and virtio. And at least for virtio it's a deprecated feature to start with. This should shrink the kernel size for embedded device that only use, say eMMC a bit. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-28block: don't assign cmd_flags in __blk_rq_prep_cloneChristoph Hellwig1-1/+0
These days we have the proper flags set since request allocation time. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-28block: split scsi_request out of struct requestChristoph Hellwig6-128/+87
And require all drivers that want to support BLOCK_PC to allocate it as the first thing of their private data. To support this the legacy IDE and BSG code is switched to set cmd_size on their queues to let the block layer allocate the additional space. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-28block/bsg: move queue creation into bsg_setup_queueChristoph Hellwig1-10/+11
Simply the boilerplate code needed for bsg nodes a bit. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-28block: allow specifying size for extra command dataChristoph Hellwig3-17/+54
This mirrors the blk-mq capabilities to allocate extra drivers-specific data behind struct request by setting a cmd_size field, as well as having a constructor / destructor for it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-28block: simplify blk_init_allocated_queueChristoph Hellwig1-23/+15
Return an errno value instead of the passed in queue so that the callers don't have to keep track of two queues, and move the assignment of the request_fn and lock to the caller as passing them as argument doesn't simplify anything. While we're at it also remove two pointless NULL assignments, given that the request structure is zeroed on allocation. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-28block: fix elevator init checkChristoph Hellwig1-22/+4
We can't initalize the elevator fields for flushes as flush share space in struct request with the elevator data. But currently we can't communicate that a request is a flush through blk_get_request as we can only pass READ or WRITE, and the low-level code looks at the possible NULL bio to check for a flush. Fix this by allowing to pass any block op and flags, and by checking for the flush flags in __get_request. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-28Merge branch 'for-4.11/block' into for-4.11/rq-refactorJens Axboe26-634/+2827
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-28blk-mq: fix debugfs compilation issuesOmar Sandoval3-6/+19
This fixes a couple of problems: 1. In the !CONFIG_DEBUG_FS case, the stub definitions were bogus. 2. In the !CONFIG_BLOCK case, blk-mq-debugfs.c shouldn't be compiled at all. Fix the stub definitions and add a CONFIG_BLK_DEBUG_FS Kconfig option. Fixes: 07e4fead45e6 ("blk-mq: create debugfs directory tree") Signed-off-by: Omar Sandoval <osandov@fb.com> Augment Kconfig description. Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27block: cleanup remaining manual checks for PREFLUSH|FUAJens Axboe2-2/+2
Use op_is_flush() where applicable. Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq-sched: add flush insertion into blk_mq_sched_insert_request()Jens Axboe8-55/+89
Instead of letting the caller check this and handle the details of inserting a flush request, put the logic in the scheduler insertion function. This fixes direct flush insertion outside of the usual make_request_fn calls, like from dm via blk_insert_cloned_request(). Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27block: add a op_is_flush helperChristoph Hellwig3-9/+8
This centralizes the checks for bios that needs to be go into the flush state machine. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq-sched: change ->dispatch_requests() to ->dispatch_request()Jens Axboe3-13/+22
When we invoke dispatch_requests(), the scheduler empties everything into the passed in list. This isn't always a good thing, since it means that we remove items that we could have potentially merged with. Change the function to dispatch single requests at the time. If we do that, we can backoff exactly at the point where the device can't consume more IO, and leave the rest with the scheduler for better merging and future dispatch decision making. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Tested-by: Hannes Reinecke <hare@suse.com>
2017-01-27blk-mq-sched: fix starvation for multiple hardware queues and shared tagsJens Axboe4-7/+40
If we have both multiple hardware queues and shared tag map between devices, we need to ensure that we propagate the hardware queue restart bit higher up. This is because we can get into a situation where we don't have any IO pending on a hardware queue, yet we fail getting a tag to start new IO. If that happens, it's not enough to mark the hardware queue as needing a restart, we need to bubble that up to the higher level queue as well. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Tested-by: Hannes Reinecke <hare@suse.com>
2017-01-27blk-mq: release driver tag on a requeue eventJens Axboe1-0/+16
We don't want to hold on to this resource when we have a scheduler attached. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Tested-by: Hannes Reinecke <hare@suse.com>
2017-01-27blk-mq: fix potential race in queue restart and driver tag allocationJens Axboe1-1/+9
Once we mark the queue as needing a restart, re-check if we can get a driver tag. This fixes a theoretical issue where the needed IO completes _after_ blk_mq_get_driver_tag() fails, but before we manage to set the restart bit. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Tested-by: Hannes Reinecke <hare@suse.com>
2017-01-27blk-mq: improve scheduler queue sync/async runningJens Axboe1-2/+4
We'll use the same criteria for whether we need to run the queue sync or async when we have a scheduler, as we do without one. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Tested-by: Hannes Reinecke <hare@suse.com>
2017-01-27blk-mq: move hctx and ctx counters from sysfs to debugfsOmar Sandoval2-64/+181
These counters aren't as out-of-place in sysfs as the other stuff, but debugfs is a slightly better home for them. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq: move hctx io_poll, stats, and dispatched from sysfs to debugfsOmar Sandoval2-92/+132
These statistics _might_ be useful to userspace, but it's better not to commit to an ABI for these yet. Also, the dispatched file in sysfs couldn't be cleared, so make it clearable like the others in debugfs. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq: add tags and sched_tags bitmaps to debugfsOmar Sandoval1-0/+50
These can be used to debug issues like tag leaks and stuck requests. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq: move tags and sched_tags info from sysfs to debugfsOmar Sandoval4-45/+86
These are very tied to the blk-mq tag implementation, so exposing them to sysfs isn't a great idea. Move the debugging information to debugfs and add basic entries for the number of tags and the number of reserved tags to sysfs. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq: export software queue pending map to debugfsOmar Sandoval1-0/+21
This is useful for debugging problems where we've gotten stuck with requests in the software queues. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq: add extra request information to debugfsOmar Sandoval1-1/+3
The request pointers by themselves aren't super useful. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq: move hctx->dispatch and ctx->rq_list from sysfs to debugfsOmar Sandoval2-57/+106
These lists are only useful for debugging; they definitely don't belong in sysfs. Putting them in debugfs also removes the limitation of a single page of output. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq: add hctx->{state,flags} to debugfsOmar Sandoval1-0/+42
hctx->state could come in handy for bugs where the hardware queue gets stuck in the stopped state, and hctx->flags is just useful to know. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq: create debugfs directory treeOmar Sandoval5-0/+196
In preparation for putting blk-mq debugging information in debugfs, create a directory tree mirroring the one in sysfs: # tree -d /sys/kernel/debug/block /sys/kernel/debug/block |-- nvme0n1 | `-- mq | |-- 0 | | `-- cpu0 | |-- 1 | | `-- cpu1 | |-- 2 | | `-- cpu2 | `-- 3 | `-- cpu3 `-- vda `-- mq `-- 0 |-- cpu0 |-- cpu1 |-- cpu2 `-- cpu3 Also add the scaffolding for the actual files that will go in here, either under the hardware queue or software queue directories. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27blk-mq-sched: check for successful allocation before assigning tagJens Axboe1-1/+2
We don't trigger this from the normal IO path, since we always use blocking allocations from there. But Bart saw it testing multipath dm, since that is a heavy user of atomic request allocations in the map and clone path. Reported-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-26blk-mq: don't lose flags passed in to blk_mq_alloc_request()Jens Axboe2-4/+4
If we come in from blk_mq_alloc_requst() with NOWAIT set in flags, we must ensure that we don't later overwrite that in blk_mq_sched_get_request(). Initialize alloc_data->flags before passing it in. Reported-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-25blk-mq: only apply active queue tag throttling for driver tagsJens Axboe2-10/+15
If we have a scheduler attached, we have two sets of tags. We don't want to apply our active queue throttling for the scheduler side of tags, that only applies to driver tags since that's the resource we need to dispatch an IO. Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-23cfq-iosched: Adjust one function call together with a variable assignmentMarkus Elfring1-2/+4
The script "checkpatch.pl" pointed information out like the following. ERROR: do not use assignment in if condition Thus fix the affected source code place. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-23blk-throttle: Adjust two function calls together with a variable assignmentMarkus Elfring1-2/+4
The script "checkpatch.pl" pointed information out like the following. ERROR: do not use assignment in if condition Thus fix the affected source code places. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-23block: Initialize cfqq->ioprio_class in cfq_get_queue()Alexander Potapenko1-0/+2
KMSAN (KernelMemorySanitizer, a new error detection tool) reports use of uninitialized memory in cfq_init_cfqq(): ================================================================== BUG: KMSAN: use of unitialized memory ... Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff8202ac97>] dump_stack+0x157/0x1d0 lib/dump_stack.c:51 [<ffffffff813e9b65>] kmsan_report+0x205/0x360 ??:? [<ffffffff813eabbb>] __msan_warning+0x5b/0xb0 ??:? [< inline >] cfq_init_cfqq block/cfq-iosched.c:3754 [<ffffffff8201e110>] cfq_get_queue+0xc80/0x14d0 block/cfq-iosched.c:3857 ... origin: [<ffffffff8103ab37>] save_stack_trace+0x27/0x50 arch/x86/kernel/stacktrace.c:67 [<ffffffff813e836b>] kmsan_internal_poison_shadow+0xab/0x150 ??:? [<ffffffff813e88ab>] kmsan_poison_slab+0xbb/0x120 ??:? [< inline >] allocate_slab mm/slub.c:1627 [<ffffffff813e533f>] new_slab+0x3af/0x4b0 mm/slub.c:1641 [< inline >] new_slab_objects mm/slub.c:2407 [<ffffffff813e0ef3>] ___slab_alloc+0x323/0x4a0 mm/slub.c:2564 [< inline >] __slab_alloc mm/slub.c:2606 [< inline >] slab_alloc_node mm/slub.c:2669 [<ffffffff813dfb42>] kmem_cache_alloc_node+0x1d2/0x1f0 mm/slub.c:2746 [<ffffffff8201d90d>] cfq_get_queue+0x47d/0x14d0 block/cfq-iosched.c:3850 ... ================================================================== (the line numbers are relative to 4.8-rc6, but the bug persists upstream) The uninitialized struct cfq_queue is created by kmem_cache_alloc_node() and then passed to cfq_init_cfqq(), which accesses cfqq->ioprio_class before it's initialized. Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-22 08:02:49 +0300