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2014-09-25powerpc: Implement emulation of string loads and storesPaul Mackerras
The size field of the op.type word is now the total number of bytes to be loaded or stored. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Emulate icbi, mcrf and conditional-trap instructionsPaul Mackerras
This extends the instruction emulation done by analyse_instr() and emulate_step() to handle a few more instructions that are found in the kernel. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Split out instruction analysis part of emulate_step()Paul Mackerras
This splits out the instruction analysis part of emulate_step() into a separate analyse_instr() function, which decodes the instruction, but doesn't execute any load or store instructions. It does execute integer instructions and branches which can be executed purely by updating register values in the pt_regs struct. For other instructions, it returns the instruction type and other details in a new instruction_op struct. emulate_step() then uses that information to execute loads, stores, cache operations, mfmsr, mtmsr[d], and (on 64-bit) sc instructions. The reason for doing this is so that the KVM code can use it instead of having its own separate instruction emulation code. Possibly the alignment interrupt handler could also use this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Check flat device tree version at bootMichael Ellerman
In commit e6a6928c3ea1 "of/fdt: Convert FDT functions to use libfdt", the kernel stopped supporting old flat device tree formats. The minimum supported version is now 0x10. There was a checking function added, early_init_dt_verify(), but it's not called on powerpc. The result is, if you boot with an old flat device tree, the kernel will fail to parse it correctly, think you have no memory etc. and hilarity ensues. We can't really fix it, but we can at least catch the fact that the device tree is in an unsupported format and panic(). We can't call BUG(), it's too early. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc/powernv: Don't call generic code on offline cpusPaul Mackerras
On PowerNV platforms, when a CPU is offline, we put it into nap mode. It's possible that the CPU wakes up from nap mode while it is still offline due to a stray IPI. A misdirected device interrupt could also potentially cause it to wake up. In that circumstance, we need to clear the interrupt so that the CPU can go back to nap mode. In the past the clearing of the interrupt was accomplished by briefly enabling interrupts and allowing the normal interrupt handling code (do_IRQ() etc.) to handle the interrupt. This has the problem that this code calls irq_enter() and irq_exit(), which call functions such as account_system_vtime() which use RCU internally. Use of RCU is not permitted on offline CPUs and will trigger errors if RCU checking is enabled. To avoid calling into any generic code which might use RCU, we adopt a different method of clearing interrupts on offline CPUs. Since we are on the PowerNV platform, we know that the system interrupt controller is a XICS being driven directly (i.e. not via hcalls) by the kernel. Hence this adds a new icp_native_flush_interrupt() function to the native-mode XICS driver and arranges to call that when an offline CPU is woken from nap. This new function reads the interrupt from the XICS. If it is an IPI, it clears the IPI; if it is a device interrupt, it prints a warning and disables the source. Then it does the end-of-interrupt processing for the interrupt. The other thing that briefly enabling interrupts did was to check and clear the irq_happened flag in this CPU's PACA. Therefore, after flushing the interrupt from the XICS, we also clear all bits except the PACA_IRQ_HARD_DIS (interrupts are hard disabled) bit from the irq_happened flag. The PACA_IRQ_HARD_DIS flag is set by power7_nap() and is left set to indicate that interrupts are hard disabled. This means we then have to ignore that flag in power7_nap(), which is reasonable since it doesn't indicate that any interrupt event needs servicing. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Use CONFIG_ARCH_HAS_FAST_MULTIPLIERAnton Blanchard
I ran some tests to compare hash_64 using shifts and multiplies. The results: POWER6: ~2x slower POWER7: ~2x faster POWER8: ~2x faster Now we have a proper config option, select CONFIG_ARCH_HAS_FAST_MULTIPLIER on POWER7 and POWER8. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Add POWER8 CPU selectionAnton Blanchard
This allows the user to build a kernel targeted at POWER8 (ie gcc -mcpu=power8). Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25pseries: Fix endian issues in cpu hot-removalThomas Falcon
When removing a cpu, this patch makes sure that values gotten from or passed to firmware are in the correct endian format. Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25pseries: Fix endian issues in onlining cpu threadsThomas Falcon
The ibm,ppc-interrupt-server#s property is in big endian format. These values need to be converted when used by little endian architectures. Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Simplify symbol check in prom_init_check.shAndreas Schwab
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: make of_device_ids constUwe Kleine-König
of_device_ids (i.e. compatible strings and the respective data) are not supposed to change at runtime. All functions working with of_device_ids provided by <linux/of.h> work with const of_device_ids. This allows to mark all struct of_device_id const, too. While touching these line also put the __init annotation at the right position where necessary. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc/jump_label: use HAVE_JUMP_LABEL?Zhouyi Zhou
CONFIG_JUMP_LABEL doesn't ensure HAVE_JUMP_LABEL, if it is not the case use maintainers's own mutex to guard the modification of global values. Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Export dcr_ind_lock to fix build errorPranith Kumar
Fix build error caused by missing export: ERROR: "dcr_ind_lock" [drivers/net/ethernet/ibm/emac/ibm_emac.ko] undefined! Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Move htab_remove_mapping function prototype into header fileAnton Blanchard
A recent patch added a function prototype for htab_remove_mapping in c code. Fix it. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Remove stale function prototypesAnton Blanchard
There were a number of prototypes for functions that no longer exist. Remove them. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Ensure global functions include their prototypeAnton Blanchard
Fix a number of places where global functions were not including their prototype. This ensures the prototype and the function match. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Make a bunch of things staticAnton Blanchard
Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Separate ppc32 symbol exports into ppc_ksyms_32.cAnton Blanchard
Simplify things considerably by moving all the ppc32 specific symbol exports into its own file. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Move lib symbol exports into arch/powerpc/lib/ppc_ksyms.cAnton Blanchard
Move the lib symbol exports closer to their function definitions Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Remove unused 32bit symbol exportsAnton Blanchard
Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Move more symbol exports next to function definitionsAnton Blanchard
Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Move via-cuda symbol exports next to function definitionsAnton Blanchard
Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Move adb symbol exports next to function definitionsAnton Blanchard
Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc/powernv: Check OPAL dump calls exist before usingMichael Neuling
Check that the OPAL_DUMP_READ token exists before initalising the elog infrastructure. This avoids littering the OPAL console with: "OPAL: Called with bad token 91" Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc/powernv: Check OPAL elog calls exist before usingMichael Neuling
Check that the OPAL_ELOG_READ token exists before initalising the elog infrastructure. This avoids littering the OPAL console with: "OPAL: Called with bad token 74" Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc/powernv: Check OPAL RTC calls exists before usingMichael Neuling
Check that the OPAL_RTC_READ token exists before we use the OPAL RTC. Refactors the code a little to merge error paths. This avoids littering the OPAL console with: "OPAL: Called with bad token 3". Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc/powernv: Add OPAL check token callMichael Neuling
Currently there is no way to generically check if an OPAL call exists or not from the host kernel. This adds an OPAL call opal_check_token() which tells you if the given token is present in OPAL or not. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc: Fix build error with CONFIG_PCI=nPranith Kumar
Fix ppc 32 build failure as reported here: http://kisskb.ellerman.id.au/kisskb/buildresult/11663513/ The error is as follows: arch/powerpc/include/asm/floppy.h:142:20: error: 'isa_bridge_pcidev' undeclared (first use in this function) This is happening since floppy.o is enabled by BLK_DEV_FD which depends on ARCH_MAY_HAVE_PC_FDC which is in-turn enabled if PPC_PSERIES=n. The following commit changes the dependency so that ARCH_MAY_HAVE_PC_FDC is dependent exclusively on PCI since otherwise it will not compile. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> CC: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc/boot: Don't install zImage.* from make installTony Breeds
in commit 29f1aff2c (powerpc: Copy bootable images in the default install script) we changed to copying all the built boot targets based on the assumption that it's backwards compatible. It turns out that debian devived installkernel scripts will barf if not given exactly 4 args. This change reverts make install to just install the vmlinux (we can change the dfault in a seperate patch) and introduces a new make zInstall which works with a more flexible installkernel script. Cc: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Tony Breeds <tony@bakeyournoodle.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25powerpc/powernv: Improve error messages in dump codeVasant Hegde
Presently we only support initiating Service Processor dump from host. Hence update sysfs message. Also update couple of other error/info messages. Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-23powerpc/pseries: Drop unnecessary continueHimangi Saraogi
Continue is not needed at the bottom of a loop. The Coccinelle semantic patch implementing this change is: @@ @@ for (...;...;...) { ... if (...) { ... - continue; } } Signed-off-by: Himangi Saraogi <himangi774@gmail.com> Acked-by: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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>
2014-09-14don't bugger nd->seq on set_root_rcu() from follow_dotdot_rcu()Al Viro
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 Torvalds
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 Torvalds
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 Gleixner
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 Jiang
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 Mason
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 Mason
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 Viro
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 Viro
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 Viro
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 Torvalds
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 Martin
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 Torvalds
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 Torvalds
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>