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2014-09-22block: fix blk_abort_request on blk-mqChristoph Hellwig3-2/+8
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 Lei1-1/+2
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 Axboe1-0/+11
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 Lei2-3/+0
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 Hellwig3-5/+14
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 Hellwig3-24/+39
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 Hellwig4-88/+49
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 Hellwig7-18/+18
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 Hellwig6-7/+14
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 Hellwig7-25/+14
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 Axboe485-2816/+5397
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 Axboe1-1/+5
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 Axboe1-1/+0
__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 Hellwig2-8/+4
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 Hildenbrand1-1/+3
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 Axboe1-0/+6
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 Torvalds5-22/+38
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 Hogan1-1/+1
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 Torvalds1-0/+7
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 Torvalds1-1/+8
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 Torvalds4-12/+17
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 Luck1-1/+1
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 Torvalds1-21/+18
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 Torvalds2-3/+13
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-rc5v3.17-rc5Linus Torvalds1-1/+1
2014-09-14Merge branch 'for-linus' of ↵Linus Torvalds3-23/+39
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 Torvalds2-9/+11
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 Torvalds9-8/+280
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 Viro1-2/+13
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>
2014-09-14don't bugger nd->seq on set_root_rcu() from follow_dotdot_rcu()Al Viro1-16/+17
return the value instead, and have path_init() do the assignment. Broken by "vfs: Fix absolute RCU path walk failures due to uninitialized seq number", which was Cc-stable with 2.6.38+ as destination. This one should go where it went. To avoid dummy value returned in case when root is already set (it would do no harm, actually, since the only caller that doesn't ignore the return value is guaranteed to have nd->root *not* set, but it's more obvious that way), lift the check into callers. And do the same to set_root(), to keep them in sync. Cc: stable@vger.kernel.org # 2.6.38+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-09-14Merge tag 'ntb-3.17' of git://github.com/jonmason/ntbLinus Torvalds2-3/+17
Pull ntb driver bugfixes from Jon Mason: "NTB driver fixes for queue spread and buffer alignment. Also, update to MAINTAINERS to reflect new e-mail address" * tag 'ntb-3.17' of git://github.com/jonmason/ntb: ntb: Add alignment check to meet hardware requirement MAINTAINERS: update NTB info NTB: correct the spread of queues over mw's
2014-09-14Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds4-22/+23
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull ARM irq chip fixes from Thomas Gleixner: "Another pile of ARM specific irq chip fixlets: - off by one bugs in the crossbar driver - missing annotations - a bunch of "make it compile" updates I pulled the lot today from Jason, but it has been in -next for at least a week" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip: gic-v3: Declare rdist as __percpu pointer to __iomem pointer irqchip: gic: Make gic_default_routable_irq_domain_ops static irqchip: exynos-combiner: Fix compilation error on ARM64 irqchip: crossbar: Off by one bugs in init irqchip: gic-v3: Tag all low level accessors __maybe_unused irqchip: gic-v3: Only define gic_peek_irq() when building SMP
2014-09-14Merge tag 'irqchip-urgent-3.17' of ↵Thomas Gleixner4-22/+23
git://git.infradead.org/users/jcooper/linux into irq/urgent irqchip fixes for v3.17 from Jason Cooper - GIC/GICV3: Various fixlets - crossbar: Fix off-by-one bug - exynos-combiner: Fix arm64 build error
2014-09-14ntb: Add alignment check to meet hardware requirementDave Jiang1-0/+13
The NTB translate register must have the value to be BAR size aligned. This alignment check make sure that the DMA memory allocated has the proper alignment. Another requirement for NTB to function properly with memory window BAR size greater or equal to 4M is to use the CMA feature in 3.16 kernel with the appropriate CONFIG_CMA_ALIGNMENT and CONFIG_CMA_SIZE_MBYTES set. Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
2014-09-14MAINTAINERS: update NTB infoJon Mason1-1/+2
Update my contact info to my personal email address and add Dave Jiang. Signed-off-by: Jon Mason <jon.mason@intel.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2014-09-14NTB: correct the spread of queues over mw'sJon Mason1-2/+2
The detection of an uneven number of queues on the given memory windows was not correct. The mw_num is zero based and the mod should be division to spread them evenly over the mw's. Signed-off-by: Jon Mason <jon.mason@intel.com>
2014-09-13fix bogus read_seqretry() checks introduced in b37199eAl Viro1-2/+2
read_seqretry() returns true on mismatch, not on match... Cc: stable@vger.kernel.org # 3.15+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-09-13move the call of __d_drop(anon) into __d_materialise_unique(dentry, anon)Al Viro1-2/+6
and lock the right list there Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-09-13[fix] lustre: d_make_root() does iput() on dentry allocation failureAl Viro1-1/+1
double-free is a bad thing Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-09-13Merge branches 'locking-urgent-for-linus' and 'timers-urgent-for-linus' of ↵Linus Torvalds4-48/+55
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull futex and timer fixes from Thomas Gleixner: "A oneliner bugfix for the jinxed futex code: - Drop hash bucket lock in the error exit path. I really could slap myself for intruducing that bug while fixing all the other horror in that code three month ago ... and the timer department is not too proud about the following fixes: - Deal with a long standing rounding bug in the timeval to jiffies conversion. It's a real issue and this fix fell through the cracks for quite some time. - Another round of alarmtimer fixes. Finally this code gets used more widely and the subtle issues hidden for quite some time are noticed and fixed. Nothing really exciting, just the itty bitty details which bite the serious users here and there" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: futex: Unlock hb->lock in futex_wait_requeue_pi() error path * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: alarmtimer: Lock k_itimer during timer callback alarmtimer: Do not signal SIGEV_NONE timers alarmtimer: Return relative times in timer_gettime jiffies: Fix timeval conversion to jiffies
2014-09-13parisc: Implement new LWS CAS supporting 64 bit operations.Guy Martin1-4/+229
The current LWS cas only works correctly for 32bit. The new LWS allows for CAS operations of variable size. Signed-off-by: Guy Martin <gmsoft@tuxicoman.be> Cc: <stable@vger.kernel.org> # 3.13+ Signed-off-by: Helge Deller <deller@gmx.de>
2014-09-13vfs: fix bad hashing of dentriesLinus Torvalds2-4/+3
Josef Bacik found a performance regression between 3.2 and 3.10 and narrowed it down to commit bfcfaa77bdf0 ("vfs: use 'unsigned long' accesses for dcache name comparison and hashing"). He reports: "The test case is essentially for (i = 0; i < 1000000; i++) mkdir("a$i"); On xfs on a fio card this goes at about 20k dir/sec with 3.2, and 12k dir/sec with 3.10. This is because we spend waaaaay more time in __d_lookup on 3.10 than in 3.2. The new hashing function for strings is suboptimal for < sizeof(unsigned long) string names (and hell even > sizeof(unsigned long) string names that I've tested). I broke out the old hashing function and the new one into a userspace helper to get real numbers and this is what I'm getting: Old hash table had 1000000 entries, 0 dupes, 0 max dupes New hash table had 12628 entries, 987372 dupes, 900 max dupes We had 11400 buckets with a p50 of 30 dupes, p90 of 240 dupes, p99 of 567 dupes for the new hash My test does the hash, and then does the d_hash into a integer pointer array the same size as the dentry hash table on my system, and then just increments the value at the address we got to see how many entries we overlap with. As you can see the old hash function ended up with all 1 million entries in their own bucket, whereas the new one they are only distributed among ~12.5k buckets, which is why we're using so much more CPU in __d_lookup". The reason for this hash regression is two-fold: - On 64-bit architectures the down-mixing of the original 64-bit word-at-a-time hash into the final 32-bit hash value is very simplistic and suboptimal, and just adds the two 32-bit parts together. In particular, because there is no bit shuffling and the mixing boundary is also a byte boundary, similar character patterns in the low and high word easily end up just canceling each other out. - the old byte-at-a-time hash mixed each byte into the final hash as it hashed the path component name, resulting in the low bits of the hash generally being a good source of hash data. That is not true for the word-at-a-time case, and the hash data is distributed among all the bits. The fix is the same in both cases: do a better job of mixing the bits up and using as much of the hash data as possible. We already have the "hash_32|64()" functions to do that. Reported-by: Josef Bacik <jbacik@fb.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-13Make hash_64() use a 64-bit multiply when appropriateLinus Torvalds1-0/+4
The hash_64() function historically does the multiply by the GOLDEN_RATIO_PRIME_64 number with explicit shifts and adds, because unlike the 32-bit case, gcc seems unable to turn the constant multiply into the more appropriate shift and adds when required. However, that means that we generate those shifts and adds even when the architecture has a fast multiplier, and could just do it better in hardware. Use the now-cleaned-up CONFIG_ARCH_HAS_FAST_MULTIPLIER (together with "is it a 64-bit architecture") to decide whether to use an integer multiply or the explicit sequence of shift/add instructions. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-13Make ARCH_HAS_FAST_MULTIPLIER a real config variableLinus Torvalds5-6/+8
It used to be an ad-hoc hack defined by the x86 version of <asm/bitops.h> that enabled a couple of library routines to know whether an integer multiply is faster than repeated shifts and additions. This just makes it use the real Kconfig system instead, and makes x86 (which was the only architecture that did this) select the option. NOTE! Even for x86, this really is kind of wrong. If we cared, we would probably not enable this for builds optimized for netburst (P4), where shifts-and-adds are generally faster than multiplies. This patch does *not* change that kind of logic, though, it is purely a syntactic change with no code changes. This was triggered by the fact that we have other places that really want to know "do I want to expand multiples by constants by hand or not", particularly the hash generation code. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-13Merge tag 'dm-3.17-fix2' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper fix from Mike Snitzer: "Fix a race in the DM cache target that caused dirty blocks to be marked as clean. This could cause no writeback to occur or spurious dirty block counts" * tag 'dm-3.17-fix2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm cache: fix race causing dirty blocks to be marked as clean
2014-09-13Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds7-47/+123
Pull block fixes from Jens Axboe: "A small collection of fixes for the current rc series. This contains: - Two small blk-mq patches from Rob Elliott, cleaning up error case at init time. - A fix from Ming Lei, fixing SG merging for blk-mq where QUEUE_FLAG_SG_NO_MERGE is the default. - A dev_t minor lifetime fix from Keith, fixing an issue where a minor might be reused before all references to it were gone. - Fix from Alan Stern where an unbalanced queue bypass caused SCSI some headaches when it does a series of add/del on devices without fully registrering the queue. - A fix from me for improving the scaling of tag depth in blk-mq if we are short on memory" * 'for-linus' of git://git.kernel.dk/linux-block: blk-mq: scale depth and rq map appropriate if low on memory Block: fix unbalanced bypass-disable in blk_register_queue block: Fix dev_t minor allocation lifetime blk-mq: cleanup after blk_mq_init_rq_map failures blk-mq: pass along blk_mq_alloc_tag_set return values blk-merge: fix blk_recount_segments
2014-09-12Merge tag 'stable/for-linus-3.17-b-rc4-arm-tag' of ↵Linus Torvalds7-93/+220
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen ARM bugfix from Stefano Stabellini: "The patches fix the "xen_add_mach_to_phys_entry: cannot add" bug that has been affecting xen on arm and arm64 guests since 3.16. They require a few hypervisor side changes that just went in xen-unstable. A couple of days ago David sent out a pull request with a few other Xen fixes (it is already in master). Sorry we didn't synchronized better among us" * tag 'stable/for-linus-3.17-b-rc4-arm-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/arm: remove mach_to_phys rbtree xen/arm: reimplement xen_dma_unmap_page & friends xen/arm: introduce XENFEAT_grant_map_identity
2014-09-12alarmtimer: Lock k_itimer during timer callbackRichard Larocque1-2/+8
Locks the k_itimer's it_lock member when handling the alarm timer's expiry callback. The regular posix timers defined in posix-timers.c have this lock held during timout processing because their callbacks are routed through posix_timer_fn(). The alarm timers follow a different path, so they ought to grab the lock somewhere else. Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Sharvil Nanavati <sharvil@google.com> Signed-off-by: Richard Larocque <rlarocque@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-09-12alarmtimer: Do not signal SIGEV_NONE timersRichard Larocque1-2/+4
Avoids sending a signal to alarm timers created with sigev_notify set to SIGEV_NONE by checking for that special case in the timeout callback. The regular posix timers avoid sending signals to SIGEV_NONE timers by not scheduling any callbacks for them in the first place. Although it would be possible to do something similar for alarm timers, it's simpler to handle this as a special case in the timeout. Prior to this patch, the alarm timer would ignore the sigev_notify value and try to deliver signals to the process anyway. Even worse, the sanity check for the value of sigev_signo is skipped when SIGEV_NONE was specified, so the signal number could be bogus. If sigev_signo was an unitialized value (as it often would be if SIGEV_NONE is used), then it's hard to predict which signal will be sent. Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Sharvil Nanavati <sharvil@google.com> Signed-off-by: Richard Larocque <rlarocque@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-09-12alarmtimer: Return relative times in timer_gettimeRichard Larocque1-7/+11
Returns the time remaining for an alarm timer, rather than the time at which it is scheduled to expire. If the timer has already expired or it is not currently scheduled, the it_value's members are set to zero. This new behavior matches that of the other posix-timers and the POSIX specifications. This is a change in user-visible behavior, and may break existing applications. Hopefully, few users rely on the old incorrect behavior. Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Sharvil Nanavati <sharvil@google.com> Signed-off-by: Richard Larocque <rlarocque@google.com> [jstultz: minor style tweak] Signed-off-by: John Stultz <john.stultz@linaro.org>