| Age | Commit message (Collapse) | Author |
|---|
|
The calculation of the DMA residue for the Tegra APB DMA is duplicated
in two places in the tegra_dma_tx_status() function. Remove this
duplicated code by moving calculation to the end of the function and
only calculating if we found a valid descriptor.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
Correct the grammar in the debug message when no descriptor is found.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
mbr_ds is an integer, don't use %pad to print it.
Fixes: commit 268914f4e7a0 ("dmaengine: at_xdmac: use %pad format string for dma_addr_t")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
The omap_dmaxbar_init() function is not exported or declared outside
the driver, so make it static to fix the following sparse warning:
drivers/dma/ti-dma-crossbar.c:455:5: warning: symbol 'omap_dmaxbar_init' was not declared. Should it be static?
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
If kzalloc() fails it will issue it's own error message including
a dump_stack(). So remove the site specific error messages.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
There is no point calculating the residue if there is
no txstate to store the value.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
There is no point in calculating the residue if state does not
exist to store the value.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
There is no point calculating the residue if there is
no txstate to store the value.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
Doing so saves a few lines of code in the driver.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
There is no point in calculating the residue if there is no
txstate to store the value.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
It is useful to print the error code as part of the error
message.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
Currently fsl-edma doesn't clk_disable_unprepare()
its clocks on error conditions. This patch adds a
fsl_disable_clocks helper for this, and also only
disables clocks which were enabled if encountering
an error whilst enabling clocks.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
The AXI CDMA is a soft ip, which can be programmed to support
32 bit addressing or greater than 32 bit addressing.
When the AXI CDMA ip is configured for 32 bit address space
in simple dma mode the source/destination buffer address is
specified by a single register(18h for Source buffer address and
20h for Destination buffer address). When configured in SG mode
the current descriptor and tail descriptor are specified by a
Single register(08h for curdesc 10h for tail desc).
When the AXI CDMA core is configured for an address space greater
than 32 then each buffer address or descriptor address is specified by
a combination of two registers.
The first register specifies the LSB 32 bits of address,
while the next register specifies the MSB 32 bits of address.
For example, 08h will specify the LSB 32 bits while 0Ch will
specify the MSB 32 bits of the first start address.
So we need to program two registers at a time.
This patch adds the 64 bit addressing support to the axicdma
IP in the driver.
Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
The AXI DMA is a soft ip, which can be programmed to support
32 bit addressing or greater than 32 bit addressing.
When the AXI DMA ip is configured for 32 bit address space
in simple dma mode the buffer address is specified by a single register
(18h for MM2S channel and 48h for S2MM channel). When configured in SG mode
The current descriptor and tail descriptor are specified by a single
Register(08h for curdesc 10h for tail desc for MM2S channel and 38h for
Curdesc and 40h for tail desc for S2MM).
When the AXI DMA core is configured for an address space greater
than 32 then each buffer address or descriptor address is specified by
a combination of two registers.
The first register specifies the LSB 32 bits of address,
while the next register specifies the MSB 32 bits of address.
For example, 48h will specify the LSB 32 bits while 4Ch will
specify the MSB 32 bits of the first start address.
So we need to program two registers at a time.
This patch adds the 64 bit addressing support for the axidma
IP in the driver.
Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
There are some places where whitespace is used in very funky ways. Fix
the most serious ones to make the code easier on the eye.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
The newly added xilinx_dma_prep_dma_cyclic function sometimes causes
a gcc warning about the use of the segment function in case
we never run into the inner loop of the function:
dma/xilinx/xilinx_vdma.c: In function 'xilinx_dma_prep_dma_cyclic':
dma/xilinx/xilinx_vdma.c:1808:23: error: 'segment' may be used uninitialized in this function [-Werror=maybe-uninitialized]
segment->hw.control |= XILINX_DMA_BD_SOP;
This can only happen if the period len is zero (which would cause other
problems earlier), or if the buffer is shorter than a period. Neither
of them should ever happen, but by adding an explicit check for these two
cases, we can abort in a more controlled way, and the compiler is
able to see that we never use uninitialized data.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
This patch fixes the below compilation warining.
drivers/dma/xilinx/xilinx_vdma.c: In function 'xilinx_dma_prep_dma_cyclic':
drivers/dma/xilinx/xilinx_vdma.c:1808:23: warning: 'segment' may be used
uninitialized in this function [-Wmaybe-uninitialized]
segment->hw.control |= XILINX_DMA_BD_SOP;
The start of packet (SOP) should be set to the first segment in the desc
chain not for the last segment of the desc chain.
Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
The bcm2835_dma_prep_dma_memcpy() function is not exported
outside the driver, so make it static to avoid the following
warning:
drivers/dma/bcm2835-dma.c:616:32: warning: symbol 'bcm2835_dma_prep_dma_memcpy' was not declared. Should it be static?
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
The at_xdmac_init_used_desc() and at_xdmac_prep_dma_memset()
functions are not exported outside the driver, so make them
static to avoid the following warnings:
drivers/dma/at_xdmac.c:459:6: warning: symbol 'at_xdmac_init_used_desc' was not declared. Should it be static?
drivers/dma/at_xdmac.c:1205:32: warning: symbol 'at_xdmac_prep_dma_memset' was not declared. Should it be static?
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
The sirfsoc_dmadata structs are not used outside the driver, so
remove build warnings by making them static. Fixes:
drivers/dma/sirf-dma.c:1129:24: warning: symbol 'sirfsoc_dmadata_a6' was not declared. Should it be static?
drivers/dma/sirf-dma.c:1134:24: warning: symbol 'sirfsoc_dmadata_a7v1' was not declared. Should it be static?
drivers/dma/sirf-dma.c:1139:24: warning: symbol 'sirfsoc_dmadata_a7v2' was not declared. Should it be static?
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
Fix warning due to d40_width_to_bits() not being used outside
this file. Fixes:
drivers/dma/ste_dma40_ll.c:13:4: warning: symbol 'd40_width_to_bits' was not declared. Should it be static?
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
The driver limits the physical number of paRAM slots to be used by channels.
If the transfer needs more slots (more SGs) then the transfer is broken up
to smaller chunks. When the chunk is finished the driver will rewrite the
physical slots and continues the transfer. This set up time can take some
time and we might miss DMA events. If the intermediate set completion is
using early completion (the interrupt will happen when the last slot is
issued to the TPTC and not when the transfer is finished by the TPTC) we
will have a bit more time to update the paRAM slots and less likely to have
missed events.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
Remove the space before the "err_free_dma:" label in mv_xor_channel_add().
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
dma_pool_zalloc combines dma_pool_alloc and memset 0
this patch updates the driver to use dma_pool_zalloc.
Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
This patch adds support for AXI DMA cyclic dma mode.
In cyclic mode, DMA fetches and processes the same
BDs without interruption. The DMA continues to fetch and process
until it is stopped or reset.
Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
For each descriptor, in addition to the memory used by the descriptors
structure itself, the driver allocates a list of chunks as well as a
buffer for hardware descriptors. Descriptors themselves are preallocated,
and allocation of the chunks and buffer is performed the first time the
descriptor is used. The memory isn't freed when the transfer is completed,
as the chunks and buffer will be needed again when the descriptor is
reused internally, so the driver keeps the memory around.
If only a few descriptors are used concurrently, the current
list_add_tail() implementation will result in all preallocated descriptors
being used before going back to the first one, and will thus allocate
chunks and a buffer for all preallocated descriptors. Using list_add()
will put the complete descriptor at the head of the list of available
descriptors, so the next transfer will be more likely to reuse a
descriptor that already has associated memory instead of one that has
never been used before.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
|
|
|
|
The self-test was updated to cover zero-length strings; the function
needs to be updated, too.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Fixes: fcfd2fbf22d2 ("fs/namei.c: Add hashlen_string() function")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The original name was simply hash_string(), but that conflicted with a
function with that name in drivers/base/power/trace.c, and I decided
that calling it "hashlen_" was better anyway.
But you have to do it in two places.
[ This caused build errors for architectures that don't define
CONFIG_DCACHE_WORD_ACCESS - Linus ]
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Fixes: fcfd2fbf22d2 ("fs/namei.c: Add hashlen_string() function")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The HPFS filesystem used generic_show_options to produce string that is
displayed in /proc/mounts. However, there is a problem that the options
may disappear after remount. If we mount the filesystem with option1
and then remount it with option2, /proc/mounts should show both option1
and option2, however it only shows option2 because the whole option
string is replaced with replace_mount_options in hpfs_remount_fs.
To fix this bug, implement the hpfs_show_options function that prints
options that are currently selected.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Commit c8f33d0bec99 ("affs: kstrdup() memory handling") checks if the
kstrdup function returns NULL due to out-of-memory condition.
However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL. In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists. The mount syscall then fails with
ENOMEM.
This patch fixes the bug. We fail with ENOMEM only if data is non-NULL.
The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).
Fixes: c8f33d0bec99 ("affs: kstrdup() memory handling")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org # v4.1+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Commit ce657611baf9 ("hpfs: kstrdup() out of memory handling") checks if
the kstrdup function returns NULL due to out-of-memory condition.
However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL. In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists. The mount syscall then fails with
ENOMEM.
This patch fixes the bug. We fail with ENOMEM only if data is non-NULL.
The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).
Fixes: ce657611baf9 ("hpfs: kstrdup() out of memory handling")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Pull more MIPS updates from Ralf Baechle:
"This is the secondnd batch of MIPS patches for 4.7. Summary:
CPS:
- Copy EVA configuration when starting secondary VPs.
EIC:
- Clear Status IPL.
Lasat:
- Fix a few off by one bugs.
lib:
- Mark intrinsics notrace. Not only are the intrinsics
uninteresting, it would cause infinite recursion.
MAINTAINERS:
- Add file patterns for MIPS BRCM device tree bindings.
- Add file patterns for mips device tree bindings.
MT7628:
- Fix MT7628 pinmux typos.
- wled_an pinmux gpio.
- EPHY LEDs pinmux support.
Pistachio:
- Enable KASLR
VDSO:
- Build microMIPS VDSO for microMIPS kernels.
- Fix aliasing warning by building with `-fno-strict-aliasing' for
debugging but also tracing them might result in recursion.
Misc:
- Add missing FROZEN hotplug notifier transitions.
- Fix clk binding example for varioius PIC32 devices.
- Fix cpu interrupt controller node-names in the DT files.
- Fix XPA CPU feature separation.
- Fix write_gc0_* macros when writing zero.
- Add inline asm encoding helpers.
- Add missing VZ accessor microMIPS encodings.
- Fix little endian microMIPS MSA encodings.
- Add 64-bit HTW fields and fix its configuration.
- Fix sigreturn via VDSO on microMIPS kernel.
- Lots of typo fixes.
- Add definitions of SegCtl registers and use them"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (49 commits)
MIPS: Add missing FROZEN hotplug notifier transitions
MIPS: Build microMIPS VDSO for microMIPS kernels
MIPS: Fix sigreturn via VDSO on microMIPS kernel
MIPS: devicetree: fix cpu interrupt controller node-names
MIPS: VDSO: Build with `-fno-strict-aliasing'
MIPS: Pistachio: Enable KASLR
MIPS: lib: Mark intrinsics notrace
MIPS: Fix 64-bit HTW configuration
MIPS: Add 64-bit HTW fields
MAINTAINERS: Add file patterns for mips device tree bindings
MAINTAINERS: Add file patterns for mips brcm device tree bindings
MIPS: Simplify DSP instruction encoding macros
MIPS: Add missing tlbinvf/XPA microMIPS encodings
MIPS: Fix little endian microMIPS MSA encodings
MIPS: Add missing VZ accessor microMIPS encodings
MIPS: Add inline asm encoding helpers
MIPS: Spelling fix lets -> let's
MIPS: VR41xx: Fix typo
MIPS: oprofile: Fix typo
MIPS: math-emu: Fix typo
...
|
|
Various builds (such as i386:allmodconfig) fail with
fs/binfmt_aout.c:133:2: error: expected identifier or '(' before 'return'
fs/binfmt_aout.c:134:1: error: expected identifier or '(' before '}' token
[ Oops. My bad, I had stupidly thought that "allmodconfig" covered this
on x86-64 too, but it obviously doesn't. Egg on my face. - Linus ]
Fixes: 5d22fc25d4fc ("mm: remove more IS_ERR_VALUE abuses")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Pull string hash improvements from George Spelvin:
"This series does several related things:
- Makes the dcache hash (fs/namei.c) useful for general kernel use.
(Thanks to Bruce for noticing the zero-length corner case)
- Converts the string hashes in <linux/sunrpc/svcauth.h> to use the
above.
- Avoids 64-bit multiplies in hash_64() on 32-bit platforms. Two
32-bit multiplies will do well enough.
- Rids the world of the bad hash multipliers in hash_32.
This finishes the job started in commit 689de1d6ca95 ("Minimal
fix-up of bad hashing behavior of hash_64()")
The vast majority of Linux architectures have hardware support for
32x32-bit multiply and so derive no benefit from "simplified"
multipliers.
The few processors that do not (68000, h8/300 and some models of
Microblaze) have arch-specific implementations added. Those
patches are last in the series.
- Overhauls the dcache hash mixing.
The patch in commit 0fed3ac866ea ("namei: Improve hash mixing if
CONFIG_DCACHE_WORD_ACCESS") was an off-the-cuff suggestion.
Replaced with a much more careful design that's simultaneously
faster and better. (My own invention, as there was noting suitable
in the literature I could find. Comments welcome!)
- Modify the hash_name() loop to skip the initial HASH_MIX(). This
would let us salt the hash if we ever wanted to.
- Sort out partial_name_hash().
The hash function is declared as using a long state, even though
it's truncated to 32 bits at the end and the extra internal state
contributes nothing to the result. And some callers do odd things:
- fs/hfs/string.c only allocates 32 bits of state
- fs/hfsplus/unicode.c uses it to hash 16-bit unicode symbols not bytes
- Modify bytemask_from_count to handle inputs of 1..sizeof(long)
rather than 0..sizeof(long)-1. This would simplify users other
than full_name_hash"
Special thanks to Bruce Fields for testing and finding bugs in v1. (I
learned some humbling lessons about "obviously correct" code.)
On the arch-specific front, the m68k assembly has been tested in a
standalone test harness, I've been in contact with the Microblaze
maintainers who mostly don't care, as the hardware multiplier is never
omitted in real-world applications, and I haven't heard anything from
the H8/300 world"
* 'hash' of git://ftp.sciencehorizons.net/linux:
h8300: Add <asm/hash.h>
microblaze: Add <asm/hash.h>
m68k: Add <asm/hash.h>
<linux/hash.h>: Add support for architecture-specific functions
fs/namei.c: Improve dcache hash function
Eliminate bad hash multipliers from hash_32() and hash_64()
Change hash_64() return value to 32 bits
<linux/sunrpc/svcauth.h>: Define hash_str() in terms of hashlen_string()
fs/namei.c: Add hashlen_string() function
Pull out string hash to <linux/stringhash.h>
|
|
This will improve the performance of hash_32() and hash_64(), but due
to complete lack of multi-bit shift instructions on H8, performance will
still be bad in surrounding code.
Designing H8-specific hash algorithms to work around that is a separate
project. (But if the maintainers would like to get in touch...)
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
|
|
Microblaze is an FPGA soft core that can be configured various ways.
If it is configured without a multiplier, the standard __hash_32()
will require a call to __mulsi3, which is a slow software loop.
Instead, use a shift-and-add sequence for the constant multiply.
GCC knows how to do this, but it's not as clever as some.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Alistair Francis <alistair.francis@xilinx.com>
Cc: Michal Simek <michal.simek@xilinx.com>
|
|
This provides a multiply by constant GOLDEN_RATIO_32 = 0x61C88647
for the original mc68000, which lacks a 32x32-bit multiply instruction.
Yes, the amount of optimization effort put in is excessive. :-)
Shift-add chain found by Yevgen Voronenko's Hcub algorithm at
http://spiral.ece.cmu.edu/mcm/gen.html
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Philippe De Muyter <phdm@macq.eu>
Cc: linux-m68k@lists.linux-m68k.org
|
|
This is just the infrastructure; there are no users yet.
This is modelled on CONFIG_ARCH_RANDOM; a CONFIG_ symbol declares
the existence of <asm/hash.h>.
That file may define its own versions of various functions, and define
HAVE_* symbols (no CONFIG_ prefix!) to suppress the generic ones.
Included is a self-test (in lib/test_hash.c) that verifies the basics.
It is NOT in general required that the arch-specific functions compute
the same thing as the generic, but if a HAVE_* symbol is defined with
the value 1, then equality is tested.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Philippe De Muyter <phdm@macq.eu>
Cc: linux-m68k@lists.linux-m68k.org
Cc: Alistair Francis <alistai@xilinx.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
|
|
Patch 0fed3ac866 improved the hash mixing, but the function is slower
than necessary; there's a 7-instruction dependency chain (10 on x86)
each loop iteration.
Word-at-a-time access is a very tight loop (which is good, because
link_path_walk() is one of the hottest code paths in the entire kernel),
and the hash mixing function must not have a longer latency to avoid
slowing it down.
There do not appear to be any published fast hash functions that:
1) Operate on the input a word at a time, and
2) Don't need to know the length of the input beforehand, and
3) Have a single iterated mixing function, not needing conditional
branches or unrolling to distinguish different loop iterations.
One of the algorithms which comes closest is Yann Collet's xxHash, but
that's two dependent multiplies per word, which is too much.
The key insights in this design are:
1) Barring expensive ops like multiplies, to diffuse one input bit
across 64 bits of hash state takes at least log2(64) = 6 sequentially
dependent instructions. That is more cycles than we'd like.
2) An operation like "hash ^= hash << 13" requires a second temporary
register anyway, and on a 2-operand machine like x86, it's three
instructions.
3) A better use of a second register is to hold a two-word hash state.
With careful design, no temporaries are needed at all, so it doesn't
increase register pressure. And this gets rid of register copying
on 2-operand machines, so the code is smaller and faster.
4) Using two words of state weakens the requirement for one-round mixing;
we now have two rounds of mixing before cancellation is possible.
5) A two-word hash state also allows operations on both halves to be
done in parallel, so on a superscalar processor we get more mixing
in fewer cycles.
I ended up using a mixing function inspired by the ChaCha and Speck
round functions. It is 6 simple instructions and 3 cycles per iteration
(assuming multiply by 9 can be done by an "lea" instruction):
x ^= *input++;
y ^= x; x = ROL(x, K1);
x += y; y = ROL(y, K2);
y *= 9;
Not only is this reversible, two consecutive rounds are reversible:
if you are given the initial and final states, but not the intermediate
state, it is possible to compute both input words. This means that at
least 3 words of input are required to create a collision.
(It also has the property, used by hash_name() to avoid a branch, that
it hashes all-zero to all-zero.)
The rotate constants K1 and K2 were found by experiment. The search took
a sample of random initial states (I used 1023) and considered the effect
of flipping each of the 64 input bits on each of the 128 output bits two
rounds later. Each of the 8192 pairs can be considered a biased coin, and
adding up the Shannon entropy of all of them produces a score.
The best-scoring shifts also did well in other tests (flipping bits in y,
trying 3 or 4 rounds of mixing, flipping all 64*63/2 pairs of input bits),
so the choice was made with the additional constraint that the sum of the
shifts is odd and not too close to the word size.
The final state is then folded into a 32-bit hash value by a less carefully
optimized multiply-based scheme. This also has to be fast, as pathname
components tend to be short (the most common case is one iteration!), but
there's some room for latency, as there is a fair bit of intervening logic
before the hash value is used for anything.
(Performance verified with "bonnie++ -s 0 -n 1536:-2" on tmpfs. I need
a better benchmark; the numbers seem to show a slight dip in performance
between 4.6.0 and this patch, but they're too noisy to quote.)
Special thanks to Bruce fields for diligent testing which uncovered a
nasty fencepost error in an earlier version of this patch.
[checkpatch.pl formatting complaints noted and respectfully disagreed with.]
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Tested-by: J. Bruce Fields <bfields@redhat.com>
|
|
The "simplified" prime multipliers made very bad hash functions, so get rid
of them. This completes the work of 689de1d6ca.
To avoid the inefficiency which was the motivation for the "simplified"
multipliers, hash_64() on 32-bit systems is changed to use a different
algorithm. It makes two calls to hash_32() instead.
drivers/media/usb/dvb-usb-v2/af9015.c uses the old GOLDEN_RATIO_PRIME_32
for some horrible reason, so it inherits a copy of the old definition.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
|
|
That's all that's ever asked for, and it makes the return
type of hash_long() consistent.
It also allows (upcoming patch) an optimized implementation
of hash_64 on 32-bit machines.
I tried adding a BUILD_BUG_ON to ensure the number of bits requested
was never more than 32 (most callers use a compile-time constant), but
adding <linux/bug.h> to <linux/hash.h> breaks the tools/perf compiler
unless tools/perf/MANIFEST is updated, and understanding that code base
well enough to update it is too much trouble. I did the rest of an
allyesconfig build with such a check, and nothing tripped.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
|
|
Finally, the first use of previous two patches: eliminate the
separate ad-hoc string hash functions in the sunrpc code.
Now hash_str() is a wrapper around hash_string(), and hash_mem() is
likewise a wrapper around full_name_hash().
Note that sunrpc code *does* call hash_mem() with a zero length, which
is why the previous patch needed to handle that in full_name_hash().
(Thanks, Bruce, for finding that!)
This also eliminates the only caller of hash_long which asks for
more than 32 bits of output.
The comment about the quality of hashlen_string() and full_name_hash()
is jumping the gun by a few patches; they aren't very impressive now,
but will be improved greatly later in the series.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: linux-nfs@vger.kernel.org
|
|
We'd like to make more use of the highly-optimized dcache hash functions
throughout the kernel, rather than have every subsystem create its own,
and a function that hashes basic null-terminated strings is required
for that.
(The name is to emphasize that it returns both hash and length.)
It's actually useful in the dcache itself, specifically d_alloc_name().
Other uses in the next patch.
full_name_hash() is also tweaked to make it more generally useful:
1) Take a "char *" rather than "unsigned char *" argument, to
be consistent with hash_name().
2) Handle zero-length inputs. If we want more callers, we don't want
to make them worry about corner cases.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
|
|
... so they can be used without the rest of <linux/dcache.h>
The hashlen_* macros will make sense next patch.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fix from Wolfram Sang:
"A fix for a regression introduced yesterday.
The regression didn't show up here locally because I did not have
PAGE_POISONING enabled. And buildbots discovered this only after it
hit your tree. Thanks to Dan for the quick response"
* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: dev: use after free in detach
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/olof/chrome-platform
Pull chrome platform updates from Olof Johansson
"A handful of Chrome driver and binding changes this merge window:
- a few patches to fix probing and configuration of pstore
- a few patches adding Elan touchpad registration on a few devices
- EC changes: a security fix dealing with max message sizes and
addition of compat_ioctl support.
- keyboard backlight control support
There was also an accidential duplicate registration of trackpads on
'Leon', which was reverted just recently"
* tag 'chrome-platform' of git://git.kernel.org/pub/scm/linux/kernel/git/olof/chrome-platform:
Revert "platform/chrome: chromeos_laptop: Add Leon Touch"
platform/chrome: chromeos_laptop - Add Elan touchpad for Wolf
platform/chrome: chromeos_laptop - Add elan trackpad option for C720
platform/chrome: cros_ec_dev - Populate compat_ioctl
platform/chrome: cros_ec_lightbar - use name instead of ID to hide lightbar attributes
platform/chrome: cros_ec_dev - Fix security issue
platform/chrome: Add Chrome OS keyboard backlight LEDs support
platform/chrome: use to_platform_device()
platform/chrome: pstore: Move to larger record size.
platform/chrome: pstore: probe for ramoops buffer using acpi
platform/chrome: chromeos_laptop: Add Leon Touch
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull more sound updates from Takashi Iwai:
"This is the second update round for 4.7-rc1. Most of changes are
about the pending ASoC updates and fixes, including a few new drivers.
Below are some highlights:
ASoC:
- New drivers for MAX98371 and TAS5720
- SPI support for TLV320AIC32x4, along with the module split
- TDM support for STI Uniperf IPs
- Remaining topology API fixes / updates
HDA:
- A couple of Dell quirks and new Realtek codec support"
* tag 'sound-4.7-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (63 commits)
ALSA: hda - Fix headset mic detection problem for one Dell machine
spi: spi-ep93xx: Fix the PTR_ERR() argument
ALSA: hda/realtek - Add support for ALC295/ALC3254
ASoC: kirkwood: fix build failure
ALSA: hda - Fix headphone noise on Dell XPS 13 9360
ASoC: ak4642: Enable cache usage to fix crashes on resume
ASoC: twl6040: Disconnect AUX output pads on digital mute
ASoC: tlv320aic32x4: Properly implement the positive and negative pins into the mixers
rcar: src: skip disabled-SRC nodes
ASoC: max98371 Remove duplicate entry in max98371_reg
ASoC: twl6040: Select LPPLL during standby
ASoC: rsnd: don't use prohibited number to PDMACHCRn.SRS
ASoC: simple-card: Add pm callbacks to platform driver
ASoC: pxa: Fix module autoload for platform drivers
ASoC: topology: Fix memory leak in widget creation
ASoC: Add max98371 codec driver
ASoC: rsnd: count .probe/.remove for rsnd_mod_call()
ASoC: topology: Check size mismatch of ABI objects before parsing
ASoC: topology: Check failure to create a widget
ASoC: add support for TAS5720 digital amplifier
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending
Pull SCSI target updates from Nicholas Bellinger:
"Here are the outstanding target pending updates for v4.7-rc1.
The highlights this round include:
- Allow external PR/ALUA metadata path be defined at runtime via top
level configfs attribute (Lee)
- Fix target session shutdown bug for ib_srpt multi-channel (hch)
- Make TFO close_session() and shutdown_session() optional (hch)
- Drop se_sess->sess_kref + convert tcm_qla2xxx to internal kref
(hch)
- Add tcm_qla2xxx endpoint attribute for basic FC jammer (Laurence)
- Refactor iscsi-target RX/TX PDU encode/decode into common code
(Varun)
- Extend iscsit_transport with xmit_pdu, release_cmd, get_rx_pdu,
validate_parameters, and get_r2t_ttt for generic ISO offload
(Varun)
- Initial merge of cxgb iscsi-segment offload target driver (Varun)
The bulk of the changes are Chelsio's new driver, along with a number
of iscsi-target common code improvements made by Varun + Co along the
way"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (29 commits)
iscsi-target: Fix early sk_data_ready LOGIN_FLAGS_READY race
cxgbit: Use type ISCSI_CXGBIT + cxgbit tpg_np attribute
iscsi-target: Convert transport drivers to signal rdma_shutdown
iscsi-target: Make iscsi_tpg_np driver show/store use generic code
tcm_qla2xxx Add SCSI command jammer/discard capability
iscsi-target: graceful disconnect on invalid mapping to iovec
target: need_to_release is always false, remove redundant check and kfree
target: remove sess_kref and ->shutdown_session
iscsi-target: remove usage of ->shutdown_session
tcm_qla2xxx: introduce a private sess_kref
target: make close_session optional
target: make ->shutdown_session optional
target: remove acl_stop
target: consolidate and fix session shutdown
cxgbit: add files for cxgbit.ko
iscsi-target: export symbols
iscsi-target: call complete on conn_logout_comp
iscsi-target: clear tx_thread_active
iscsi-target: add new offload transport type
iscsi-target: use conn_transport->transport_type in text rsp
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma
Pull more rdma updates from Doug Ledford:
"This is the second group of code for the 4.7 merge window. It looks
large, but only in one sense. I'll get to that in a minute. The list
of changes here breaks down as follows:
- Dynamic counter infrastructure in the IB drivers
This is a sysfs based code to allow free form access to the
hardware counters RDMA devices might support so drivers don't need
to code this up repeatedly themselves
- SendOnlyFullMember multicast support
- IB router support
- A couple misc fixes
- The big item on the list: hfi1 driver updates, plus moving the hfi1
driver out of staging
There was a group of 15 patches in the hfi1 list that I thought I had
in the first pull request but they weren't. So that added to the
length of the hfi1 section here.
As far as these go, everything but the hfi1 is pretty straight
forward.
The hfi1 is, if you recall, the driver that Al had complaints about
how it used the write/writev interfaces in an overloaded fashion. The
write portion of their interface behaved like the write handler in the
IB stack proper and did bi-directional communications. The writev
interface, on the other hand, only accepts SDMA request structures.
The completions for those structures are sent back via an entirely
different event mechanism.
With the security patch, we put security checks on the write
interface, however, we also knew they would be going away soon. Now,
we've converted the write handler in the hfi1 driver to use ioctls
from the IB reserved magic area for its bidirectional communications.
With that change, Intel has addressed all of the items originally on
their TODO when they went into staging (as well as many items added to
the list later).
As such, I moved them out, and since they were the last item in the
staging/rdma directory, and I don't have immediate plans to use the
staging area again, I removed the staging/rdma area.
Because of the move out of staging, as well as a series of 5 patches
in the hfi1 driver that removed code people thought should be done in
a different way and was optional to begin with (a snoop debug
interface, an eeprom driver for an eeprom connected directory to their
hfi1 chip and not via an i2c bus, and a few other things like that),
the line count, especially the removal count, is high"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (56 commits)
staging/rdma: Remove the entire rdma subdirectory of staging
IB/core: Make device counter infrastructure dynamic
IB/hfi1: Fix pio map initialization
IB/hfi1: Correct 8051 link parameter settings
IB/hfi1: Update pkey table properly after link down or FM start
IB/rdamvt: Fix rdmavt s_ack_queue sizing
IB/rdmavt: Max atomic value should be a u8
IB/hfi1: Fix hard lockup due to not using save/restore spin lock
IB/hfi1: Add tracing support for send with invalidate opcode
IB/hfi1, qib: Add ieth to the packet header definitions
IB/hfi1: Move driver out of staging
IB/hfi1: Do not free hfi1 cdev parent structure early
IB/hfi1: Add trace message in user IOCTL handling
IB/hfi1: Remove write(), use ioctl() for user cmds
IB/hfi1: Add ioctl() interface for user commands
IB/hfi1: Remove unused user command
IB/hfi1: Remove snoop/diag interface
IB/hfi1: Remove EPROM functionality from data device
IB/hfi1: Remove UI char device
IB/hfi1: Remove multiple device cdev
...
|
