We want to hide drm_atomic_stat internals a bit better.
v2: Use drm_crtc_mask (Maarten).
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464818821-5736-7-git-send-email-daniel.vetter@ffwll.ch
We want to hide drm_atomic_state internals
v2: Review from Maarten:
- remove whitespace change in rockchip driver that slipped in.
- use drm_crtc_mask insted of open-coding it.
Cc: Rob Clark <robdclark@gmail.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464818821-5736-4-git-send-email-daniel.vetter@ffwll.ch
This avois leaking drm_atomic_state internals into the helpers. The
only place where this still happens after this patch is drm_atomic_helper_swap_state().
It's unavoidable there, and maybe a good indicator we should actually
move that function into drm_atomic.c.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464818821-5736-2-git-send-email-daniel.vetter@ffwll.ch
The intention of using video=<connector>:<mode> is primarily to select
the user's preferred resolution at startup. Currently we always create a
new mode irrespective of whether the monitor has a native mode at the
desired resolution. This has the issue that we may then select the fake
mode rather the native mode during fb_helper->inital_config() and so
if the fake mode is invalid we then end up with a loss of signal. Oops.
This invalid fake mode would also be exported to userspace, who
potentially may make the same mistake.
To avoid this issue, we filter out the added command line mode if we
detect the desired resolution (and clock if specified) amongst the
probed modes. This fixes the immediate problem of adding a duplicate
mode, but perhaps more generically we should avoid adding a GTF mode if
the monitor has an EDID that is not GTF-compatible, or similarly for
CVT.
Was meant to fix a regression from
commit eaf99c749d
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed Aug 6 10:08:32 2014 +0200
drm: Perform cmdline mode parsing during connector initialisation
but Radek explained that the original bug is no longer reproducible on
latest kernels.
v2: Explicitly delete our earlier cmdline mode
v3: Mode pruning should now be sufficient to delete stale cmdline modes
v4: Compute the vrefresh for the probed mode
Reported-by: Radek Dostál <rd@radekdostal.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Radek Dostál <rd@radekdostal.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: Julia Lemire <jlemire@matrox.com>
Cc: Dave Airlie <airlied@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Drop cc: stable since no longer a pressing bugfix, just
nice-to-have.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464774651-20376-1-git-send-email-chris@chris-wilson.co.uk
If @signal_on_any is true the fence array signals if any fence in the array
signals, otherwise it signals when all fences in the array signal.
v2: fix signaled test and add comment suggested by Chris Wilson.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464786612-5010-4-git-send-email-deathsimple@vodafone.de
struct fence_array inherits from struct fence and carries a
collection of fences that needs to be waited together.
It is useful to translate a sync_file to a fence to remove the complexity
of dealing with sync_files on DRM drivers. So even if there are many
fences in the sync_file that needs to waited for a commit to happen,
they all get added to the fence_collection and passed for DRM use as
a standard struct fence.
That means that no changes needed to any driver besides supporting fences.
To avoid fence_array's fence allocates a new timeline if needed (when
combining fences from different timelines).
v2: Comments by Daniel Vetter:
- merge fence_collection_init() and fence_collection_add()
- only add callbacks at ->enable_signalling()
- remove fence_collection_put()
- check for type on to_fence_collection()
- adjust fence_is_later() and fence_later() to WARN_ON() if they
are used with collection fences.
v3: - Initialize fence_cb.node at fence init.
Comments by Chris Wilson:
- return "unbound" on fence_collection_get_timeline_name()
- don't stop adding callbacks if one fails
- remove redundant !! on fence_collection_enable_signaling()
- remove redundant () on fence_collection_signaled
- use fence_default_wait() instead
v4 (chk): Rework, simplification and cleanup:
- Drop FENCE_NO_CONTEXT handling, always allocate a context.
- Rename to fence_array.
- Return fixed driver name.
- Register only one callback at a time.
- Document that create function takes ownership of array.
v5 (chk): More work and fixes:
- Avoid deadlocks by adding all callbacks at once again.
- Stop trying to remove the callbacks.
- Provide context and sequence number for the array fence.
v6 (chk): Fixes found during testing
- Fix stupid typo in _enable_signaling().
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
[danvet: Improve commit message as suggested by Gustavo.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464786612-5010-3-git-send-email-deathsimple@vodafone.de
Fence contexts are created on the fly (for example) by the GPU scheduler used
in the amdgpu driver as a result of an userspace request. Because of this
userspace could in theory force a wrap around of the 32bit context number
if it doesn't behave well.
Avoid this by increasing the context number to 64bits. This way even when
userspace manages to allocate a billion contexts per second it takes more
than 500 years for the context number to wrap around.
v2: fix printf formats as well.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464786612-5010-2-git-send-email-deathsimple@vodafone.de
Since commit 4dfd64862f ("drm: Use vblank timestamps to guesstimate
how many vblanks were missed"), the DRM framework can cope with devices
that don't have a hardware counter for vsync events without having
to keep the vsync interrupts enabled all the time. Drivers handling
such hardware should use drm_vblank_no_hw_counter() function for
their ->get_vblank_counter hook.
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464795342-32297-1-git-send-email-Liviu.Dudau@arm.com
Fallback drm_atomic_helper_best_encoder() is funcs->best_encoder() is NULL
so that DRM drivers can leave this hook unassigned if they know they want
to use drm_atomic_helper_best_encoder().
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20160601180337.28e0917b@bbrezillon
drm-intel-next-2016-05-22:
- cmd-parser support for direct reg->reg loads (Ken Graunke)
- better handle DP++ smart dongles (Ville)
- bxt guc fw loading support (Nick Hoathe)
- remove a bunch of struct typedefs from dpll code (Ander)
- tons of small work all over to avoid casting between drm_device and the i915
dev struct (Tvrtko&Chris)
- untangle request retiring from other operations, also fixes reset stat corner
cases (Chris)
- skl atomic watermark support from Matt Roper, yay!
- various wm handling bugfixes from Ville
- big pile of cdclck rework for bxt/skl (Ville)
- CABC (Content Adaptive Brigthness Control) for dsi panels (Jani&Deepak M)
- nonblocking atomic commits for plane-only updates (Maarten Lankhorst)
- bunch of PSR fixes&improvements
- untangle our map/pin/sg_iter code a bit (Dave Gordon)
drm-intel-next-2016-05-08:
- refactor stolen quirks to share code between early quirks and i915 (Joonas)
- refactor gem BO/vma funcstion (Tvrtko&Dave)
- backlight over DPCD support (Yetunde Abedisi)
- more dsi panel sequence support (Jani)
- lots of refactoring around handling iomaps, vma, ring access and related
topics culmulating in removing the duplicated request tracking in the execlist
code (Chris & Tvrtko) includes a small patch for core iomapping code
- hw state readout for bxt dsi (Ramalingam C)
- cdclk cleanups (Ville)
- dedupe chv pll code a bit (Ander)
- enable semaphores on gen8+ for legacy submission, to be able to have a direct
comparison against execlist on the same platform (Chris) Not meant to be used
for anything else but performance tuning
- lvds border bit hw state checker fix (Jani)
- rpm vs. shrinker/oom-notifier fixes (Praveen Paneri)
- l3 tuning (Imre)
- revert mst dp audio, it's totally non-functional and crash-y (Lyude)
- first official dmc for kbl (Rodrigo)
- and tons of small things all over as usual
* 'drm-intel-next' of git://anongit.freedesktop.org/drm-intel: (194 commits)
drm/i915: Revert async unpin and nonblocking atomic commit
drm/i915: Update DRIVER_DATE to 20160522
drm/i915: Inline sg_next() for the optimised SGL iterator
drm/i915: Introduce & use new lightweight SGL iterators
drm/i915: optimise i915_gem_object_map() for small objects
drm/i915: refactor i915_gem_object_pin_map()
drm/i915/psr: Implement PSR2 w/a for gen9
drm/i915/psr: Use ->get_aux_send_ctl functions
drm/i915/psr: Order DP aux transactions correctly
drm/i915/psr: Make idle_frames sensible again
drm/i915/psr: Try to program link training times correctly
drm/i915/userptr: Convert to drm_i915_private
drm/i915: Allow nonblocking update of pageflips.
drm/i915: Check for unpin correctness.
Reapply "drm/i915: Avoid stalling on pending flips for legacy cursor updates"
drm/i915: Make unpin async.
drm/i915: Prepare connectors for nonblocking checks.
drm/i915: Pass atomic states to fbc update functions.
drm/i915: Remove reset_counter from intel_crtc.
drm/i915: Remove queue_flip pointer.
...
Frist -misc pull for 4.8, with pretty much just random all over plus a few
more lockless gem BO patches acked/reviewed by driver maintainers.
I'm starting a bit earlier this time around because there's a few invasive
patch series to land (nonblocking atomic prep work, fence prep work,
rst/sphinx kerneldoc finally happening) and I need a baseline with all the
branches merged.
* tag 'topic/drm-misc-2016-06-01' of git://anongit.freedesktop.org/drm-intel: (21 commits)
drm/vc4: Use lockless gem BO free callback
drm/vc4: Use drm_gem_object_unreference_unlocked
drm: Initialize a linear gamma table by default
drm/vgem: Use lockless gem BO free callback
drm/qxl: Don't set a gamma table size
drm/msm: Nuke dummy gamma_set/get functions
drm/cirrus: Drop redundnant gamma size check
drm/fb-helper: Remove dead code in setcolreg
drm/mediatek: Use lockless gem BO free callback
drm/hisilicon: Use lockless gem BO free callback
drm/hlcd: Use lockless gem BO free callback
vga_switcheroo: Support deferred probing of audio clients
vga_switcheroo: Add helper for deferred probing
virtio-gpu: fix output lookup
drm/doc: Unify KMS Locking docs
drm/atomic-helper: Do not call ->mode_fixup for CRTC which will be disabled
Fix annoyingly awkward typo in drm_edid_load.c
drm/doc: Drop vblank_disable_allow wording
drm: use seqlock for vblank time/count
drm/mm: avoid possible null pointer dereference
...
This reverts the following patches:
d55dbd06bb drm/i915: Allow nonblocking update of pageflips.
15c86bdb76 drm/i915: Check for unpin correctness.
95c2ccdc82 Reapply "drm/i915: Avoid stalling on pending flips for legacy cursor updates"
a6747b7304 drm/i915: Make unpin async.
03f476e1fc drm/i915: Prepare connectors for nonblocking checks.
2099deffef drm/i915: Pass atomic states to fbc update functions.
ee7171af72 drm/i915: Remove reset_counter from intel_crtc.
2ee004f7c5 drm/i915: Remove queue_flip pointer.
b8d2afae55 drm/i915: Remove use_mmio_flip kernel parameter.
8dd634d922 drm/i915: Remove cs based page flip support.
143f73b3bf drm/i915: Rework intel_crtc_page_flip to be almost atomic, v3.
84fc494b64 drm/i915: Add the exclusive fence to plane_state.
6885843ae1 drm/i915: Convert flip_work to a list.
aa420ddd8e drm/i915: Allow mmio updates on all platforms, v2.
afee4d8707 Revert "drm/i915: Avoid stalling on pending flips for legacy cursor updates"
"drm/i915: Allow nonblocking update of pageflips" should have been
split up, misses a proper commit message and seems to cause issues in
the legacy page_flip path as demonstrated by kms_flip.
"drm/i915: Make unpin async" doesn't handle the unthrottled cursor
updates correctly, leading to an apparent pin count leak. This is
caught by the WARN_ON in i915_gem_object_do_pin which screams if we
have more than DRM_I915_GEM_OBJECT_MAX_PIN_COUNT pins.
Unfortuantely we can't just revert these two because this patch series
came with a built-in bisect breakage in the form of temporarily
removing the unthrottled cursor update hack for legacy cursor ioctl.
Therefore there's no other option than to revert the entire pile :(
There's one tiny conflict in intel_drv.h due to other patches, nothing
serious.
Normally I'd wait a bit longer with doing a maintainer revert, but
since the minimal set of patches we need to revert (due to the bisect
breakage) is so big, time is running out fast. And very soon
(especially after a few attempts at fixing issues) it'll be really
hard to revert things cleanly.
Lessons learned:
- Not a good idea to rush the review (done by someone fairly new to
the area) and not make sure domain experts had a chance to read it.
- Patches should be properly split up. I only looked at the two
patches that should be reverted in detail, but both look like the
mix up different things in one patch.
- Patches really should have proper commit messages. Especially when
doing more than one thing, and especially when touching critical and
tricky core code.
- Building a patch series and r-b stamping it when it has a built-in
bisect breakage is not a good idea.
- I also think we need to stop building up technical debt by
postponing atomic igt testcases even longer. I think it's clear that
there's enough corner cases in this beast that we really need to
have the testcases _before_ the next step lands.
(cherry picked from commit 5a21b6650a
from drm-intel-next-queeud)
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Since my last struct_mutex crusade someone escaped!
This already has the advantage that for the common case when someone
else holds a ref the unref won't even acquire dev->struct_mutex. And
I'm working on code to allow drivers to completely opt-out of any and
all dev->struct_mutex usage, but that only works if they use the
_unlocked variants everywhere.
v2: Drop comment too.
v3: Drop the other comment too.
Cc: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464630800-30786-15-git-send-email-daniel.vetter@ffwll.ch
Code stolen from gma500.
This is just a minor bit of safety code that I spotted and figured it
might be useful if we put it into the core. This is to make the
get_gamma ioctl reflect likely reality even before the first set_gamma
ioctl call.
v2 on irc: Extend commit message per Maarten's suggestions.
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459331485-28376-2-git-send-email-daniel.vetter@ffwll.ch
qxl doesn't have any functions for setting the gamma table, so this is
completely defunct.
Not nice to lie to userspace, so let's stop!
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1459331485-28376-10-git-send-email-daniel.vetter@ffwll.ch
Again the fbdev emulation gamma_set/get functions are only needed for
drivers that try to also use 8bpp paletted mode. Which msm doesn't, so
this is dead code. Let's rip it out.
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1459331485-28376-7-git-send-email-daniel.vetter@ffwll.ch
DRM fbdev emulation only supports pallete_color with depth == 8, and
truecolor with depth > 8. Handling depth == 16 for palettes is hence
dead code, let's remove it.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1459331485-28376-3-git-send-email-daniel.vetter@ffwll.ch
Daniel Vetter pointed out that vga_switcheroo_client_probe_defer() could
be needed by audio clients as well. To avoid mistakes when someone adds
conditions for these in the future, constrain the single existing
condition to VGA clients by checking for PCI_BASE_CLASS_DISPLAY. This
encompasses both PCI_CLASS_DISPLAY_VGA as well as PCI_CLASS_DISPLAY_3D,
which is used by some Nvidia Optimus GPUs.
Any future checks for audio clients should then be constrained to
PCI_BASE_CLASS_MULTIMEDIA.
v6: Spun out from commit introducing vga_switcheroo_client_probe_defer()
to keep it a pure refactoring change. (Emil Velikov, Jani Nikula)
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/358d58490eb9dda5f270d844b0dce511a2a20828.1464685538.git.lukas@wunner.de
So far we've got one condition when DRM drivers need to defer probing
on a dual GPU system and it's coded separately into each of the relevant
drivers. As suggested by Daniel Vetter, deduplicate that code in the
drivers and move it to a new vga_switcheroo helper. This yields better
encapsulation of concepts and lets us add further checks in a central
place. (The existing check pertains to pre-retina MacBook Pros and an
additional check is expected to be needed for retinas.)
One might be tempted to check deferred probing conditions in
vga_switcheroo_register_client(), but this is usually called fairly late
during driver load. The GPU is fully brought up and ready for switching
at that point. On boot the ->probe hook is potentially called dozens of
times until it finally succeeds, and each time we'd repeat bringup and
teardown of the GPU, lengthening boot time considerably and cluttering
logfiles. A separate helper is therefore needed which can be called
right at the beginning of the ->probe hook.
Note that amdgpu currently does not call this helper as the AMD GPUs
built into MacBook Pros are only supported by radeon so far.
v2: This helper could eventually be used by audio clients as well,
so rephrase kerneldoc to refer to "client" instead of "GPU"
and move the single existing check in an if block specific
to PCI_CLASS_DISPLAY_VGA devices. Move documentation on
that check from kerneldoc to a comment. (Daniel Vetter)
v3: Mandate in kerneldoc that registration of client shall only
happen after calling this helper. (Daniel Vetter)
v4: Rebase on 412c8f7de0 ("drm/radeon: Return -EPROBE_DEFER when
amdkfd not loaded")
v5: Some Optimus GPUs use PCI_CLASS_DISPLAY_3D, make sure those are
matched as well. (Emil Velikov)
v6: The if-condition referring to PCI_BASE_CLASS_DISPLAY may be
considered a functional change. Move to a separate commit to
keep this a pure refactoring change. (Emil Velikov, Jani Nikula)
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/575885fd440c2b13c3f19ddf44360cfbbff35f50.1464685538.git.lukas@wunner.de
When a CRTC is going to be disabled, it's state may contain a display mode
with zeroed content. This could be reproduced by HDMI cable hotplug out
operation with legacy fbdev support in dual display cases. It would confuse
driver's CRTC callback ->mode_fixup and make the total state be rejected.
So, let's don't call the callback for the CRTC.
Signed-off-by: Liu Ying <gnuiyl@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464341754-7087-1-git-send-email-gnuiyl@gmail.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: fcfd2fbf22 ("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: fcfd2fbf22 ("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 c8f33d0bec ("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: c8f33d0bec ("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 ce657611ba ("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: ce657611ba ("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>
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: 5d22fc25d4 ("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 689de1d6ca ("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 0fed3ac866 ("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>
