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2014-09-27block: Relocate bio integrity flagsMartin K. Petersen
Move flags affecting the integrity code out of the bio bi_flags and into the block integrity payload. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-27block: Add a disk flag to block integrity profileMartin K. Petersen
So far we have relied on the app tag size to determine whether a disk has been formatted with T10 protection information or not. However, not all target devices provide application tag storage. Add a flag to the block integrity profile that indicates whether the disk has been formatted with protection information. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Sagi Grimberg <sagig@dev.mellanox.co.il> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-27block: Add prefix to block integrity profile flagsMartin K. Petersen
Add a BLK_ prefix to the integrity profile flags. Also rename the flags to be more consistent with the generate/verify terminology in the rest of the integrity code. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-27block: Clean up the code used to generate and verify integrity metadataMartin K. Petersen
Instead of the "operate" parameter we pass in a seed value and a pointer to a function that can be used to process the integrity metadata. The generation function is changed to have a return value to fit into this scheme. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-27block: Make protection interval calculation genericMartin K. Petersen
Now that the protection interval has been detached from the sector size we need to be able to handle sizes that are different from 4K and 512. Make the interval calculation generic. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-27block: Deprecate the use of the term sector in the context of block integrityMartin K. Petersen
The protection interval is not necessarily tied to the logical block size of a block device. Stop using the terms "sector" and "sectors". Going forward we will use the term "seed" to describe the initial reference tag value for a given I/O. "Interval" will be used to describe the portion of the data buffer that a given piece of protection information is associated with. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-27block: Remove bip_bufMartin K. Petersen
bip_buf is not really needed so we can remove it. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-27block: Remove integrity tagging functionsMartin K. Petersen
None of the filesystems appear interested in using the integrity tagging feature. Potentially because very few storage devices actually permit using the application tag space. Remove the tagging functions. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-27block: Replace bi_integrity with bi_specialMartin K. Petersen
For commands like REQ_COPY we need a way to pass extra information along with each bio. Like integrity metadata this information must be available at the bottom of the stack so bi_private does not suffice. Rename the existing bi_integrity field to bi_special and make it a union so we can have different bio extensions for each class of command. We previously used bi_integrity != NULL as a way to identify whether a bio had integrity metadata or not. Introduce a REQ_INTEGRITY to be the indicator now that bi_special can contain different things. In addition, bio_integrity(bio) will now return a pointer to the integrity payload (when applicable). Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-27block: Get rid of bdev_integrity_enabled()Martin K. Petersen
bdev_integrity_enabled() is only used by bio_integrity_enabled(). Combine these two functions. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25blk-mq: support per-distpatch_queue flush machineryMing Lei
This patch supports to run one single flush machinery for each blk-mq dispatch queue, so that: - current init_request and exit_request callbacks can cover flush request too, then the buggy copying way of initializing flush request's pdu can be fixed - flushing performance gets improved in case of multi hw-queue In fio sync write test over virtio-blk(4 hw queues, ioengine=sync, iodepth=64, numjobs=4, bs=4K), it is observed that througput gets increased a lot over my test environment: - throughput: +70% in case of virtio-blk over null_blk - throughput: +30% in case of virtio-blk over SSD image The multi virtqueue feature isn't merged to QEMU yet, and patches for the feature can be found in below tree: git://kernel.ubuntu.com/ming/qemu.git v2.1.0-mq.4 And simply passing 'num_queues=4 vectors=5' should be enough to enable multi queue(quad queue) feature for QEMU virtio-blk. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25block: introduce 'blk_mq_ctx' parameter to blk_get_flush_queueMing Lei
This patch adds 'blk_mq_ctx' parameter to blk_get_flush_queue(), so that this function can find the corresponding blk_flush_queue bound with current mq context since the flush queue will become per hw-queue. For legacy queue, the parameter can be simply 'NULL'. For multiqueue case, the parameter should be set as the context from which the related request is originated. With this context info, the hw queue and related flush queue can be found easily. Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25block: flush: avoid to figure out flush queue unnecessarilyMing Lei
Just figuring out flush queue at the entry of kicking off flush machinery and request's completion handler, then pass it through. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25block: remove blk_init_flush() and its pairMing Lei
Now mission of the two helpers is over, and just call blk_alloc_flush_queue() and blk_free_flush_queue() directly. Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25block: introduce blk_flush_queue to drive flush machineryMing Lei
This patch introduces 'struct blk_flush_queue' and puts all flush machinery related fields into this structure, so that - flush implementation details aren't exposed to driver - it is easy to convert to per dispatch-queue flush machinery This patch is basically a mechanical replacement. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25block: avoid to use q->flush_rq directlyMing Lei
This patch trys to use local variable to access flush request, so that we can convert to per-queue flush machinery a bit easier. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25block: move flush initialization to blk_flush_initMing Lei
These fields are always used with the flush request, so initialize them together. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25block: introduce blk_init_flush and its pairMing Lei
These two temporary functions are introduced for holding flush initialization and de-initialization, so that we can introduce 'flush queue' easier in the following patch. And once 'flush queue' and its allocation/free functions are ready, they will be removed for sake of code readability. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25blk-mq: allocate flush_rq in blk_mq_init_flush()Ming Lei
It is reasonable to allocate flush req in blk_mq_init_flush(). Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-25blk-mq: handle failure path for initializing hctxMing Lei
Failure of initializing one hctx isn't handled, so this patch introduces blk_mq_init_hctx() and its pair to handle it explicitly. Also this patch makes code cleaner. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22scsi: move blk_mq_start_request call earlierChristoph Hellwig
Some ATA drivers need the dma drain size workaround, and thus need to call blk_mq_start_request before the S/G mapping. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22block: fix blk_abort_request on blk-mqChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Moved blk_mq_rq_timed_out() definition to the private blk-mq.h header. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-timeout: fix blk_add_timerMing Lei
Commit 8cb34819cdd5d(blk-mq: unshared timeout handler) introduces blk-mq's own timeout handler, and removes following line: blk_queue_rq_timed_out(q, blk_mq_rq_timed_out); which then causes blk_add_timer() to bypass adding the timer, since blk-mq no longer has q->rq_timed_out_fn defined. This patch fixes the problem by bypassing the check for blk-mq, so that both request deadlines are still set and the rolling timer updated. Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: limit memory consumption if a crash dump is activeJens Axboe
It's not uncommon for crash dump kernels to be limited to 128MB or something low in that area. This is normally not a problem for devices as we don't use that much memory, but for some shared SCSI setups with huge queue depths, it can potentially fill most of memory with tons of request allocations. blk-mq does scale back when it fails to allocate memory, but it scales back just enough so that blk-mq succeeds. This could still leave the system with not enough memory to make any real progress. Check if we are in a kdump environment and limit the hardware queues and tag depth. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: remove unnecessary blk_clear_rq_complete()Ming Lei
This patch removes two unnecessary blk_clear_rq_complete(), the REQ_ATOM_COMPLETE flag is cleared inside blk_mq_start_request(), so: - The blk_clear_rq_complete() in blk_flush_restore_request() needn't because the request will be freed later, and clearing it here may open a small race window with timeout. - The blk_clear_rq_complete() in blk_mq_requeue_request() isn't necessary too, even though REQ_ATOM_STARTED is cleared in __blk_mq_requeue_request(), in theory it still may cause a small race window with timeout since the two clear_bit() may be reordered. Signed-off-by: Ming Lei <ming.lei@canoical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: pass a reserved argument to the timeout handlerChristoph Hellwig
Allow blk-mq to pass an argument to the timeout handler to indicate if we're timing out a reserved or regular command. For many drivers those need to be handled different. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: unshared timeout handlerChristoph Hellwig
Duplicate the (small) timeout handler in blk-mq so that we can pass arguments more easily to the driver timeout handler. This enables the next patch. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: fix and simplify tag iteration for the timeout handlerChristoph Hellwig
Don't do a kmalloc from timer to handle timeouts, chances are we could be under heavy load or similar and thus just miss out on the timeouts. Fortunately it is very easy to just iterate over all in use tags, and doing this properly actually cleans up the blk_mq_busy_iter API as well, and prepares us for the next patch by passing a reserved argument to the iterator. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: rename blk_mq_end_io to blk_mq_end_requestChristoph Hellwig
Now that we've changed the driver API on the submission side use the opportunity to fix up the name on the completion side to fit into the general scheme. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: call blk_mq_start_request from ->queue_rqChristoph Hellwig
When we call blk_mq_start_request from the core blk-mq code before calling into ->queue_rq there is a racy window where the timeout handler can hit before we've fully set up the driver specific part of the command. Move the call to blk_mq_start_request into the driver so the driver can start the request only once it is fully set up. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: remove REQ_ENDChristoph Hellwig
Pass an explicit parameter for the last request in a batch to ->queue_rq instead of using a request flag. Besides being a cleaner and non-stateful interface this is also required for the next patch, which fixes the blk-mq I/O submission code to not start a time too early. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22Merge branch 'for-linus' into for-3.18/coreJens Axboe
Moving patches from for-linus to 3.18 instead, pull in this changes that will go to Linus today.
2014-09-22blk-mq: use blk_mq_start_hw_queues() when running requeue workJens Axboe
When requests are retried due to hw or sw resource shortages, we often stop the associated hardware queue. So ensure that we restart the queues when running the requeue work, otherwise the queue run will be a no-op. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: fix potential oops on out-of-memory in __blk_mq_alloc_rq_maps()Jens Axboe
__blk_mq_alloc_rq_maps() can be invoked multiple times, if we scale back the queue depth if we are low on memory. So don't clear set->tags when we fail, this is handled directly in the parent function, blk_mq_alloc_tag_set(). Reported-by: Robert Elliott <Elliott@hp.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: avoid infinite recursion with the FUA flagChristoph Hellwig
We should not insert requests into the flush state machine from blk_mq_insert_request. All incoming flush requests come through blk_{m,s}q_make_request and are handled there, while blk_execute_rq_nowait should only be called for BLOCK_PC requests. All other callers deal with requests that already went through the flush statemchine and shouldn't be reinserted into it. Reported-by: Robert Elliott <Elliott@hp.com> Debugged-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: Avoid race condition with uninitialized requestsDavid Hildenbrand
This patch should fix the bug reported in https://lkml.org/lkml/2014/9/11/249. We have to initialize at least the atomic_flags and the cmd_flags when allocating storage for the requests. Otherwise blk_mq_timeout_check() might dereference uninitialized pointers when racing with the creation of a request. Also move the reset of cmd_flags for the initializing code to the point where a request is freed. So we will never end up with pending flush request indicators that might trigger dereferences of invalid pointers in blk_mq_timeout_check(). Cc: stable@vger.kernel.org Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Reported-by: Paulo De Rezende Pinatti <ppinatti@linux.vnet.ibm.com> Tested-by: Paulo De Rezende Pinatti <ppinatti@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-22blk-mq: request deadline must be visible before marking rq as startedJens Axboe
When we start the request, we set the deadline and flip the bits marking the request as started and non-complete. However, it's important that the deadline store is ordered before flipping the bits, otherwise we could have a small window where the request is marked started but with an invalid deadline. This can confuse the timeout handling. Suggested-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-09-16Merge tag 'gfs2-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-fixes Pull gfs2 fixes from Steven Whitehouse: "Here are a number of small fixes for GFS2. There is a fix for FIEMAP on large sparse files, a negative dentry hashing fix, a fix for flock, and a bug fix relating to d_splice_alias usage. There are also (patches 1 and 5) a couple of updates which are less critical, but small and low risk" * tag 'gfs2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-fixes: GFS2: fix d_splice_alias() misuses GFS2: Don't use MAXQUOTAS value GFS2: Hash the negative dentry during inode lookup GFS2: Request demote when a "try" flock fails GFS2: Change maxlen variables to size_t GFS2: fs/gfs2/super.c: replace seq_printf by seq_puts
2014-09-16vfs: workaround gcc <4.6 build error in link_path_walk()James Hogan
Commit d6bb3e9075bb ("vfs: simplify and shrink stack frame of link_path_walk()") introduced build problems with GCC versions older than 4.6 due to the initialisation of a member of an anonymous union in struct qstr without enclosing braces. This hits GCC bug 10676 [1] (which was fixed in GCC 4.6 by [2]), and causes the following build error: fs/namei.c: In function 'link_path_walk': fs/namei.c:1778: error: unknown field 'hash_len' specified in initializer This is worked around by adding explicit braces. [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=10676 [2] https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=159206 Fixes: d6bb3e9075bb (vfs: simplify and shrink stack frame of link_path_walk()) Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-metag@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-15Merge tag 'fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull virtio fixes from Rusty Russell: "virtio-rng corner case fixes, with cc:stable. Survived a few days in linux-next" * tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: virtio-rng: skip reading when we start to remove the device virtio-rng: fix stuck of hot-unplugging busy device
2014-09-15Merge tag 'regmap-v3.17-rc5' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap Pull regmap fix from Mark Brown: "Fix registers file in debugfs Ensure that the mode reported for the registers file in debugfs is accurate by marking it as read only when the define to enable writes has not been set. This is on the edge of being a bug fix but it's debugfs and it makes it much easier for users to spot what's going wrong when they forget to enable writeability" * tag 'regmap-v3.17-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap: regmap: Fix debugfs-file 'registers' mode
2014-09-15Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input Pull input updates from Dmitry Torokhov: "A few quirks for i8042/AT keyboards and a small device tree doc fix for Atmel Touchscreens" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: Input: atmel_mxt_ts - fix merge in DT documentation Input: i8042 - also set the firmware id for MUXed ports Input: i8042 - add nomux quirk for Avatar AVIU-145A6 Input: i8042 - add Fujitsu U574 to no_timeout dmi table Input: atkbd - do not try 'deactivate' keyboard on any LG laptops
2014-09-15ia64: Fix syscall number for memfd_createTony Luck
Cut & paste typo from the line above. Reported-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-15vfs: simplify and shrink stack frame of link_path_walk()Linus Torvalds
Commit 9226b5b440f2 ("vfs: avoid non-forwarding large load after small store in path lookup") made link_path_walk() always access the "hash_len" field as a single 64-bit entity, in order to avoid mixed size accesses to the members. However, what I didn't notice was that that effectively means that the whole "struct qstr this" is now basically redundant. We already explicitly track the "const char *name", and if we just use "u64 hash_len" instead of "long len", there is nothing else left of the "struct qstr". We do end up wanting the "struct qstr" if we have a filesystem with a "d_hash()" function, but that's a rare case, and we might as well then just squirrell away the name and hash_len at that point. End result: fewer live variables in the loop, a smaller stack frame, and better code generation. And we don't need to pass in pointers variables to helper functions any more, because the return value contains all the relevant information. So this removes more lines than it adds, and the source code is clearer too. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6Linus Torvalds
Pull crypto fixes from Herbert Xu: "This fixes the newly added drbg generator so that it actually works on 32-bit machines. Previously the code was only tested on 64-bit and on 32-bit it overflowed and simply doesn't work" * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: crypto: drbg - remove check for uninitialized DRBG handle crypto: drbg - backport "fix maximum value checks on 32 bit systems"
2014-09-14Linux 3.17-rc5Linus Torvalds
2014-09-14Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs fixes from Al Viro: "double iput() on failure exit in lustre, racy removal of spliced dentries from ->s_anon in __d_materialise_dentry() plus a bunch of assorted RCU pathwalk fixes" The RCU pathwalk fixes end up fixing a couple of cases where we incorrectly dropped out of RCU walking, due to incorrect initialization and testing of the sequence locks in some corner cases. Since dropping out of RCU walk mode forces the slow locked accesses, those corner cases slowed down quite dramatically. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: be careful with nd->inode in path_init() and follow_dotdot_rcu() don't bugger nd->seq on set_root_rcu() from follow_dotdot_rcu() fix bogus read_seqretry() checks introduced in b37199e move the call of __d_drop(anon) into __d_materialise_unique(dentry, anon) [fix] lustre: d_make_root() does iput() on dentry allocation failure
2014-09-14vfs: avoid non-forwarding large load after small store in path lookupLinus Torvalds
The performance regression that Josef Bacik reported in the pathname lookup (see commit 99d263d4c5b2 "vfs: fix bad hashing of dentries") made me look at performance stability of the dcache code, just to verify that the problem was actually fixed. That turned up a few other problems in this area. There are a few cases where we exit RCU lookup mode and go to the slow serializing case when we shouldn't, Al has fixed those and they'll come in with the next VFS pull. But my performance verification also shows that link_path_walk() turns out to have a very unfortunate 32-bit store of the length and hash of the name we look up, followed by a 64-bit read of the combined hash_len field. That screws up the processor store to load forwarding, causing an unnecessary hickup in this critical routine. It's caused by the ugly calling convention for the "hash_name()" function, and easily fixed by just making hash_name() fill in the whole 'struct qstr' rather than passing it a pointer to just the hash value. With that, the profile for this function looks much smoother. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-14Merge branch 'parisc-3.17-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux Pull parisc updates from Helge Deller: "The most important patch is a new Light Weigth Syscall (LWS) for 8, 16, 32 and 64 bit atomic CAS operations which is required in order to be able to implement the atomic gcc builtins on our platform. Other than that, we wire up the seccomp, getrandom and memfd_create syscalls, fixes a minor off-by-one bug and a wrong printk string" * 'parisc-3.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: Implement new LWS CAS supporting 64 bit operations. parisc: Wire up seccomp, getrandom and memfd_create syscalls parisc: dino: fix %d confusingly prefixed with 0x in format string parisc: sys_hpux: NUL terminator is one past the end
2014-09-14be careful with nd->inode in path_init() and follow_dotdot_rcu()Al Viro
in the former we simply check if dentry is still valid after picking its ->d_inode; in the latter we fetch ->d_inode in the same places where we fetch dentry and its ->d_seq, under the same checks. Cc: stable@vger.kernel.org # 2.6.38+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>