OpenCloudOS-Kernel/include/linux/dma-resv.h

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/*
* Header file for reservations for dma-buf and ttm
*
* Copyright(C) 2011 Linaro Limited. All rights reserved.
* Copyright (C) 2012-2013 Canonical Ltd
* Copyright (C) 2012 Texas Instruments
*
* Authors:
* Rob Clark <robdclark@gmail.com>
* Maarten Lankhorst <maarten.lankhorst@canonical.com>
* Thomas Hellstrom <thellstrom-at-vmware-dot-com>
*
* Based on bo.c which bears the following copyright notice,
* but is dual licensed:
*
* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef _LINUX_RESERVATION_H
#define _LINUX_RESERVATION_H
#include <linux/ww_mutex.h>
dma-buf: Rename struct fence to dma_fence I plan to usurp the short name of struct fence for a core kernel struct, and so I need to rename the specialised fence/timeline for DMA operations to make room. A consensus was reached in https://lists.freedesktop.org/archives/dri-devel/2016-July/113083.html that making clear this fence applies to DMA operations was a good thing. Since then the patch has grown a bit as usage increases, so hopefully it remains a good thing! (v2...: rebase, rerun spatch) v3: Compile on msm, spotted a manual fixup that I broke. v4: Try again for msm, sorry Daniel coccinelle script: @@ @@ - struct fence + struct dma_fence @@ @@ - struct fence_ops + struct dma_fence_ops @@ @@ - struct fence_cb + struct dma_fence_cb @@ @@ - struct fence_array + struct dma_fence_array @@ @@ - enum fence_flag_bits + enum dma_fence_flag_bits @@ @@ ( - fence_init + dma_fence_init | - fence_release + dma_fence_release | - fence_free + dma_fence_free | - fence_get + dma_fence_get | - fence_get_rcu + dma_fence_get_rcu | - fence_put + dma_fence_put | - fence_signal + dma_fence_signal | - fence_signal_locked + dma_fence_signal_locked | - fence_default_wait + dma_fence_default_wait | - fence_add_callback + dma_fence_add_callback | - fence_remove_callback + dma_fence_remove_callback | - fence_enable_sw_signaling + dma_fence_enable_sw_signaling | - fence_is_signaled_locked + dma_fence_is_signaled_locked | - fence_is_signaled + dma_fence_is_signaled | - fence_is_later + dma_fence_is_later | - fence_later + dma_fence_later | - fence_wait_timeout + dma_fence_wait_timeout | - fence_wait_any_timeout + dma_fence_wait_any_timeout | - fence_wait + dma_fence_wait | - fence_context_alloc + dma_fence_context_alloc | - fence_array_create + dma_fence_array_create | - to_fence_array + to_dma_fence_array | - fence_is_array + dma_fence_is_array | - trace_fence_emit + trace_dma_fence_emit | - FENCE_TRACE + DMA_FENCE_TRACE | - FENCE_WARN + DMA_FENCE_WARN | - FENCE_ERR + DMA_FENCE_ERR ) ( ... ) Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Christian König <christian.koenig@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/20161025120045.28839-1-chris@chris-wilson.co.uk
2016-10-25 20:00:45 +08:00
#include <linux/dma-fence.h>
#include <linux/slab.h>
#include <linux/seqlock.h>
#include <linux/rcupdate.h>
extern struct ww_class reservation_ww_class;
struct dma_resv_list;
/**
* struct dma_resv - a reservation object manages fences for a buffer
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
*
* There are multiple uses for this, with sometimes slightly different rules in
* how the fence slots are used.
*
* One use is to synchronize cross-driver access to a struct dma_buf, either for
* dynamic buffer management or just to handle implicit synchronization between
* different users of the buffer in userspace. See &dma_buf.resv for a more
* in-depth discussion.
*
* The other major use is to manage access and locking within a driver in a
* buffer based memory manager. struct ttm_buffer_object is the canonical
* example here, since this is where reservation objects originated from. But
* use in drivers is spreading and some drivers also manage struct
* drm_gem_object with the same scheme.
*/
struct dma_resv {
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
/**
* @lock:
*
* Update side lock. Don't use directly, instead use the wrapper
* functions like dma_resv_lock() and dma_resv_unlock().
*
* Drivers which use the reservation object to manage memory dynamically
* also use this lock to protect buffer object state like placement,
* allocation policies or throughout command submission.
*/
struct ww_mutex lock;
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
/**
* @seq:
*
* Sequence count for managing RCU read-side synchronization, allows
* read-only access to @fence_excl and @fence while ensuring we take a
* consistent snapshot.
*/
seqcount_ww_mutex_t seq;
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
/**
* @fence_excl:
*
* The exclusive fence, if there is one currently.
*
* To guarantee that no fences are lost, this new fence must signal
* only after the previous exclusive fence has signalled. If
* semantically only a new access is added without actually treating the
* previous one as a dependency the exclusive fences can be strung
* together using struct dma_fence_chain.
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
*
* Note that actual semantics of what an exclusive or shared fence mean
* is defined by the user, for reservation objects shared across drivers
* see &dma_buf.resv.
*/
dma-buf: Rename struct fence to dma_fence I plan to usurp the short name of struct fence for a core kernel struct, and so I need to rename the specialised fence/timeline for DMA operations to make room. A consensus was reached in https://lists.freedesktop.org/archives/dri-devel/2016-July/113083.html that making clear this fence applies to DMA operations was a good thing. Since then the patch has grown a bit as usage increases, so hopefully it remains a good thing! (v2...: rebase, rerun spatch) v3: Compile on msm, spotted a manual fixup that I broke. v4: Try again for msm, sorry Daniel coccinelle script: @@ @@ - struct fence + struct dma_fence @@ @@ - struct fence_ops + struct dma_fence_ops @@ @@ - struct fence_cb + struct dma_fence_cb @@ @@ - struct fence_array + struct dma_fence_array @@ @@ - enum fence_flag_bits + enum dma_fence_flag_bits @@ @@ ( - fence_init + dma_fence_init | - fence_release + dma_fence_release | - fence_free + dma_fence_free | - fence_get + dma_fence_get | - fence_get_rcu + dma_fence_get_rcu | - fence_put + dma_fence_put | - fence_signal + dma_fence_signal | - fence_signal_locked + dma_fence_signal_locked | - fence_default_wait + dma_fence_default_wait | - fence_add_callback + dma_fence_add_callback | - fence_remove_callback + dma_fence_remove_callback | - fence_enable_sw_signaling + dma_fence_enable_sw_signaling | - fence_is_signaled_locked + dma_fence_is_signaled_locked | - fence_is_signaled + dma_fence_is_signaled | - fence_is_later + dma_fence_is_later | - fence_later + dma_fence_later | - fence_wait_timeout + dma_fence_wait_timeout | - fence_wait_any_timeout + dma_fence_wait_any_timeout | - fence_wait + dma_fence_wait | - fence_context_alloc + dma_fence_context_alloc | - fence_array_create + dma_fence_array_create | - to_fence_array + to_dma_fence_array | - fence_is_array + dma_fence_is_array | - trace_fence_emit + trace_dma_fence_emit | - FENCE_TRACE + DMA_FENCE_TRACE | - FENCE_WARN + DMA_FENCE_WARN | - FENCE_ERR + DMA_FENCE_ERR ) ( ... ) Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Christian König <christian.koenig@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/20161025120045.28839-1-chris@chris-wilson.co.uk
2016-10-25 20:00:45 +08:00
struct dma_fence __rcu *fence_excl;
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
/**
* @fence:
*
* List of current shared fences.
*
* There are no ordering constraints of shared fences against the
* exclusive fence slot. If a waiter needs to wait for all access, it
* has to wait for both sets of fences to signal.
*
* A new fence is added by calling dma_resv_add_shared_fence(). Since
* this often needs to be done past the point of no return in command
* submission it cannot fail, and therefore sufficient slots need to be
* reserved by calling dma_resv_reserve_shared().
*
* Note that actual semantics of what an exclusive or shared fence mean
* is defined by the user, for reservation objects shared across drivers
* see &dma_buf.resv.
*/
struct dma_resv_list __rcu *fence;
};
/**
* struct dma_resv_iter - current position into the dma_resv fences
*
* Don't touch this directly in the driver, use the accessor function instead.
*
* IMPORTANT
*
* When using the lockless iterators like dma_resv_iter_next_unlocked() or
* dma_resv_for_each_fence_unlocked() beware that the iterator can be restarted.
* Code which accumulates statistics or similar needs to check for this with
* dma_resv_iter_is_restarted().
*/
struct dma_resv_iter {
/** @obj: The dma_resv object we iterate over */
struct dma_resv *obj;
/** @all_fences: If all fences should be returned */
bool all_fences;
/** @fence: the currently handled fence */
struct dma_fence *fence;
/** @seq: sequence number to check for modifications */
unsigned int seq;
/** @index: index into the shared fences */
unsigned int index;
dma-resv: Fix dma_resv_get_fences and dma_resv_copy_fences after conversion Cache the count of shared fences in the iterator to avoid dereferencing the dma_resv_object outside the RCU protection. Otherwise iterator and its users can observe an incosistent state which makes it impossible to use safely. Such as: <6> [187.517041] [IGT] gem_sync: executing <7> [187.536343] i915 0000:00:02.0: [drm:i915_gem_context_create_ioctl [i915]] HW context 1 created <7> [187.536793] i915 0000:00:02.0: [drm:i915_gem_context_create_ioctl [i915]] HW context 1 created <6> [187.551235] [IGT] gem_sync: starting subtest basic-many-each <1> [188.935462] BUG: kernel NULL pointer dereference, address: 0000000000000010 <1> [188.935485] #PF: supervisor write access in kernel mode <1> [188.935495] #PF: error_code(0x0002) - not-present page <6> [188.935504] PGD 0 P4D 0 <4> [188.935512] Oops: 0002 [#1] PREEMPT SMP NOPTI <4> [188.935521] CPU: 2 PID: 1467 Comm: gem_sync Not tainted 5.15.0-rc4-CI-Patchwork_21264+ #1 <4> [188.935535] Hardware name: /NUC6CAYB, BIOS AYAPLCEL.86A.0049.2018.0508.1356 05/08/2018 <4> [188.935546] RIP: 0010:dma_resv_get_fences+0x116/0x2d0 <4> [188.935560] Code: 10 85 c0 7f c9 be 03 00 00 00 e8 15 8b df ff eb bd e8 8e c6 ff ff eb b6 41 8b 04 24 49 8b 55 00 48 89 e7 8d 48 01 41 89 0c 24 <4c> 89 34 c2 e8 41 f2 ff ff 49 89 c6 48 85 c0 75 8c 48 8b 44 24 10 <4> [188.935583] RSP: 0018:ffffc900011dbcc8 EFLAGS: 00010202 <4> [188.935593] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000000000001 <4> [188.935603] RDX: 0000000000000010 RSI: ffffffff822e343c RDI: ffffc900011dbcc8 <4> [188.935613] RBP: ffffc900011dbd48 R08: ffff88812d255bb8 R09: 00000000fffffffe <4> [188.935623] R10: 0000000000000001 R11: 0000000000000000 R12: ffffc900011dbd44 <4> [188.935633] R13: ffffc900011dbd50 R14: ffff888113d29cc0 R15: 0000000000000000 <4> [188.935643] FS: 00007f68d17e9700(0000) GS:ffff888277900000(0000) knlGS:0000000000000000 <4> [188.935655] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4> [188.935665] CR2: 0000000000000010 CR3: 000000012d0a4000 CR4: 00000000003506e0 <4> [188.935676] Call Trace: <4> [188.935685] i915_gem_object_wait+0x1ff/0x410 [i915] <4> [188.935988] i915_gem_wait_ioctl+0xf2/0x2a0 [i915] <4> [188.936272] ? i915_gem_object_wait+0x410/0x410 [i915] <4> [188.936533] drm_ioctl_kernel+0xae/0x140 <4> [188.936546] drm_ioctl+0x201/0x3d0 <4> [188.936555] ? i915_gem_object_wait+0x410/0x410 [i915] <4> [188.936820] ? __fget_files+0xc2/0x1c0 <4> [188.936830] ? __fget_files+0xda/0x1c0 <4> [188.936839] __x64_sys_ioctl+0x6d/0xa0 <4> [188.936848] do_syscall_64+0x3a/0xb0 <4> [188.936859] entry_SYSCALL_64_after_hwframe+0x44/0xae If the shared object has changed during the RCU unlocked period callers will correctly handle the restart on the next iteration. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Fixes: 96601e8a4755 ("dma-buf: use new iterator in dma_resv_copy_fences") Fixes: d3c80698c9f5 ("dma-buf: use new iterator in dma_resv_get_fences v3") Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4274 Cc: Christian König <christian.koenig@amd.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20211008095007.972693-1-tvrtko.ursulin@linux.intel.com Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Christian König <christian.koenig@amd.com>
2021-10-08 17:50:07 +08:00
/** @fences: the shared fences; private, *MUST* not dereference */
struct dma_resv_list *fences;
dma-resv: Fix dma_resv_get_fences and dma_resv_copy_fences after conversion Cache the count of shared fences in the iterator to avoid dereferencing the dma_resv_object outside the RCU protection. Otherwise iterator and its users can observe an incosistent state which makes it impossible to use safely. Such as: <6> [187.517041] [IGT] gem_sync: executing <7> [187.536343] i915 0000:00:02.0: [drm:i915_gem_context_create_ioctl [i915]] HW context 1 created <7> [187.536793] i915 0000:00:02.0: [drm:i915_gem_context_create_ioctl [i915]] HW context 1 created <6> [187.551235] [IGT] gem_sync: starting subtest basic-many-each <1> [188.935462] BUG: kernel NULL pointer dereference, address: 0000000000000010 <1> [188.935485] #PF: supervisor write access in kernel mode <1> [188.935495] #PF: error_code(0x0002) - not-present page <6> [188.935504] PGD 0 P4D 0 <4> [188.935512] Oops: 0002 [#1] PREEMPT SMP NOPTI <4> [188.935521] CPU: 2 PID: 1467 Comm: gem_sync Not tainted 5.15.0-rc4-CI-Patchwork_21264+ #1 <4> [188.935535] Hardware name: /NUC6CAYB, BIOS AYAPLCEL.86A.0049.2018.0508.1356 05/08/2018 <4> [188.935546] RIP: 0010:dma_resv_get_fences+0x116/0x2d0 <4> [188.935560] Code: 10 85 c0 7f c9 be 03 00 00 00 e8 15 8b df ff eb bd e8 8e c6 ff ff eb b6 41 8b 04 24 49 8b 55 00 48 89 e7 8d 48 01 41 89 0c 24 <4c> 89 34 c2 e8 41 f2 ff ff 49 89 c6 48 85 c0 75 8c 48 8b 44 24 10 <4> [188.935583] RSP: 0018:ffffc900011dbcc8 EFLAGS: 00010202 <4> [188.935593] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000000000001 <4> [188.935603] RDX: 0000000000000010 RSI: ffffffff822e343c RDI: ffffc900011dbcc8 <4> [188.935613] RBP: ffffc900011dbd48 R08: ffff88812d255bb8 R09: 00000000fffffffe <4> [188.935623] R10: 0000000000000001 R11: 0000000000000000 R12: ffffc900011dbd44 <4> [188.935633] R13: ffffc900011dbd50 R14: ffff888113d29cc0 R15: 0000000000000000 <4> [188.935643] FS: 00007f68d17e9700(0000) GS:ffff888277900000(0000) knlGS:0000000000000000 <4> [188.935655] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4> [188.935665] CR2: 0000000000000010 CR3: 000000012d0a4000 CR4: 00000000003506e0 <4> [188.935676] Call Trace: <4> [188.935685] i915_gem_object_wait+0x1ff/0x410 [i915] <4> [188.935988] i915_gem_wait_ioctl+0xf2/0x2a0 [i915] <4> [188.936272] ? i915_gem_object_wait+0x410/0x410 [i915] <4> [188.936533] drm_ioctl_kernel+0xae/0x140 <4> [188.936546] drm_ioctl+0x201/0x3d0 <4> [188.936555] ? i915_gem_object_wait+0x410/0x410 [i915] <4> [188.936820] ? __fget_files+0xc2/0x1c0 <4> [188.936830] ? __fget_files+0xda/0x1c0 <4> [188.936839] __x64_sys_ioctl+0x6d/0xa0 <4> [188.936848] do_syscall_64+0x3a/0xb0 <4> [188.936859] entry_SYSCALL_64_after_hwframe+0x44/0xae If the shared object has changed during the RCU unlocked period callers will correctly handle the restart on the next iteration. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Fixes: 96601e8a4755 ("dma-buf: use new iterator in dma_resv_copy_fences") Fixes: d3c80698c9f5 ("dma-buf: use new iterator in dma_resv_get_fences v3") Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4274 Cc: Christian König <christian.koenig@amd.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20211008095007.972693-1-tvrtko.ursulin@linux.intel.com Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Christian König <christian.koenig@amd.com>
2021-10-08 17:50:07 +08:00
/** @shared_count: number of shared fences */
unsigned int shared_count;
/** @is_restarted: true if this is the first returned fence */
bool is_restarted;
};
struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor);
struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor);
struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor);
struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor);
/**
* dma_resv_iter_begin - initialize a dma_resv_iter object
* @cursor: The dma_resv_iter object to initialize
* @obj: The dma_resv object which we want to iterate over
* @all_fences: If all fences should be returned or just the exclusive one
*/
static inline void dma_resv_iter_begin(struct dma_resv_iter *cursor,
struct dma_resv *obj,
bool all_fences)
{
cursor->obj = obj;
cursor->all_fences = all_fences;
cursor->fence = NULL;
}
/**
* dma_resv_iter_end - cleanup a dma_resv_iter object
* @cursor: the dma_resv_iter object which should be cleaned up
*
* Make sure that the reference to the fence in the cursor is properly
* dropped.
*/
static inline void dma_resv_iter_end(struct dma_resv_iter *cursor)
{
dma_fence_put(cursor->fence);
}
/**
* dma_resv_iter_is_exclusive - test if the current fence is the exclusive one
* @cursor: the cursor of the current position
*
* Returns true if the currently returned fence is the exclusive one.
*/
static inline bool dma_resv_iter_is_exclusive(struct dma_resv_iter *cursor)
{
return cursor->index == 0;
}
/**
* dma_resv_iter_is_restarted - test if this is the first fence after a restart
* @cursor: the cursor with the current position
*
* Return true if this is the first fence in an iteration after a restart.
*/
static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *cursor)
{
return cursor->is_restarted;
}
/**
* dma_resv_for_each_fence_unlocked - unlocked fence iterator
* @cursor: a struct dma_resv_iter pointer
* @fence: the current fence
*
* Iterate over the fences in a struct dma_resv object without holding the
* &dma_resv.lock and using RCU instead. The cursor needs to be initialized
* with dma_resv_iter_begin() and cleaned up with dma_resv_iter_end(). Inside
* the iterator a reference to the dma_fence is held and the RCU lock dropped.
*
* Beware that the iterator can be restarted when the struct dma_resv for
* @cursor is modified. Code which accumulates statistics or similar needs to
* check for this with dma_resv_iter_is_restarted(). For this reason prefer the
* lock iterator dma_resv_for_each_fence() whenever possible.
*/
#define dma_resv_for_each_fence_unlocked(cursor, fence) \
for (fence = dma_resv_iter_first_unlocked(cursor); \
fence; fence = dma_resv_iter_next_unlocked(cursor))
/**
* dma_resv_for_each_fence - fence iterator
* @cursor: a struct dma_resv_iter pointer
* @obj: a dma_resv object pointer
* @all_fences: true if all fences should be returned
* @fence: the current fence
*
* Iterate over the fences in a struct dma_resv object while holding the
* &dma_resv.lock. @all_fences controls if the shared fences are returned as
* well. The cursor initialisation is part of the iterator and the fence stays
* valid as long as the lock is held and so no extra reference to the fence is
* taken.
*/
#define dma_resv_for_each_fence(cursor, obj, all_fences, fence) \
for (dma_resv_iter_begin(cursor, obj, all_fences), \
fence = dma_resv_iter_first(cursor); fence; \
fence = dma_resv_iter_next(cursor))
#define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base)
#define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)
#ifdef CONFIG_DEBUG_MUTEXES
void dma_resv_reset_shared_max(struct dma_resv *obj);
#else
static inline void dma_resv_reset_shared_max(struct dma_resv *obj) {}
#endif
/**
* dma_resv_lock - lock the reservation object
* @obj: the reservation object
* @ctx: the locking context
*
* Locks the reservation object for exclusive access and modification. Note,
* that the lock is only against other writers, readers will run concurrently
* with a writer under RCU. The seqlock is used to notify readers if they
* overlap with a writer.
*
* As the reservation object may be locked by multiple parties in an
* undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
* is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
* object may be locked by itself by passing NULL as @ctx.
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
*
* When a die situation is indicated by returning -EDEADLK all locks held by
* @ctx must be unlocked and then dma_resv_lock_slow() called on @obj.
*
* Unlocked by calling dma_resv_unlock().
*
* See also dma_resv_lock_interruptible() for the interruptible variant.
*/
static inline int dma_resv_lock(struct dma_resv *obj,
struct ww_acquire_ctx *ctx)
{
return ww_mutex_lock(&obj->lock, ctx);
}
/**
* dma_resv_lock_interruptible - lock the reservation object
* @obj: the reservation object
* @ctx: the locking context
*
* Locks the reservation object interruptible for exclusive access and
* modification. Note, that the lock is only against other writers, readers
* will run concurrently with a writer under RCU. The seqlock is used to
* notify readers if they overlap with a writer.
*
* As the reservation object may be locked by multiple parties in an
* undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
* is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
* object may be locked by itself by passing NULL as @ctx.
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
*
* When a die situation is indicated by returning -EDEADLK all locks held by
* @ctx must be unlocked and then dma_resv_lock_slow_interruptible() called on
* @obj.
*
* Unlocked by calling dma_resv_unlock().
*/
static inline int dma_resv_lock_interruptible(struct dma_resv *obj,
struct ww_acquire_ctx *ctx)
{
return ww_mutex_lock_interruptible(&obj->lock, ctx);
}
/**
* dma_resv_lock_slow - slowpath lock the reservation object
* @obj: the reservation object
* @ctx: the locking context
*
* Acquires the reservation object after a die case. This function
* will sleep until the lock becomes available. See dma_resv_lock() as
* well.
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
*
* See also dma_resv_lock_slow_interruptible() for the interruptible variant.
*/
static inline void dma_resv_lock_slow(struct dma_resv *obj,
struct ww_acquire_ctx *ctx)
{
ww_mutex_lock_slow(&obj->lock, ctx);
}
/**
* dma_resv_lock_slow_interruptible - slowpath lock the reservation
* object, interruptible
* @obj: the reservation object
* @ctx: the locking context
*
* Acquires the reservation object interruptible after a die case. This function
* will sleep until the lock becomes available. See
* dma_resv_lock_interruptible() as well.
*/
static inline int dma_resv_lock_slow_interruptible(struct dma_resv *obj,
struct ww_acquire_ctx *ctx)
{
return ww_mutex_lock_slow_interruptible(&obj->lock, ctx);
}
/**
* dma_resv_trylock - trylock the reservation object
* @obj: the reservation object
*
* Tries to lock the reservation object for exclusive access and modification.
* Note, that the lock is only against other writers, readers will run
* concurrently with a writer under RCU. The seqlock is used to notify readers
* if they overlap with a writer.
*
* Also note that since no context is provided, no deadlock protection is
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
* possible, which is also not needed for a trylock.
*
* Returns true if the lock was acquired, false otherwise.
*/
static inline bool __must_check dma_resv_trylock(struct dma_resv *obj)
{
kernel/locking: Add context to ww_mutex_trylock() i915 will soon gain an eviction path that trylock a whole lot of locks for eviction, getting dmesg failures like below: BUG: MAX_LOCK_DEPTH too low! turning off the locking correctness validator. depth: 48 max: 48! 48 locks held by i915_selftest/5776: #0: ffff888101a79240 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x88/0x160 #1: ffffc900009778c0 (reservation_ww_class_acquire){+.+.}-{0:0}, at: i915_vma_pin.constprop.63+0x39/0x1b0 [i915] #2: ffff88800cf74de8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.63+0x5f/0x1b0 [i915] #3: ffff88810c7f9e38 (&vm->mutex/1){+.+.}-{3:3}, at: i915_vma_pin_ww+0x1c4/0x9d0 [i915] #4: ffff88810bad5768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] #5: ffff88810bad60e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] ... #46: ffff88811964d768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] #47: ffff88811964e0e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] INFO: lockdep is turned off. Fixing eviction to nest into ww_class_acquire is a high priority, but it requires a rework of the entire driver, which can only be done one step at a time. As an intermediate solution, add an acquire context to ww_mutex_trylock, which allows us to do proper nesting annotations on the trylocks, making the above lockdep splat disappear. This is also useful in regulator_lock_nested, which may avoid dropping regulator_nesting_mutex in the uncontended path, so use it there. TTM may be another user for this, where we could lock a buffer in a fastpath with list locks held, without dropping all locks we hold. [peterz: rework actual ww_mutex_trylock() implementations] Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/YUBGPdDDjKlxAuXJ@hirez.programming.kicks-ass.net
2021-09-09 17:32:18 +08:00
return ww_mutex_trylock(&obj->lock, NULL);
}
/**
* dma_resv_is_locked - is the reservation object locked
* @obj: the reservation object
*
* Returns true if the mutex is locked, false if unlocked.
*/
static inline bool dma_resv_is_locked(struct dma_resv *obj)
{
return ww_mutex_is_locked(&obj->lock);
}
/**
* dma_resv_locking_ctx - returns the context used to lock the object
* @obj: the reservation object
*
* Returns the context used to lock a reservation object or NULL if no context
* was used or the object is not locked at all.
dma-resv: Give the docs a do-over Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
2021-08-05 18:47:05 +08:00
*
* WARNING: This interface is pretty horrible, but TTM needs it because it
* doesn't pass the struct ww_acquire_ctx around in some very long callchains.
* Everyone else just uses it to check whether they're holding a reservation or
* not.
*/
static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj)
{
return READ_ONCE(obj->lock.ctx);
}
/**
* dma_resv_unlock - unlock the reservation object
* @obj: the reservation object
*
* Unlocks the reservation object following exclusive access.
*/
static inline void dma_resv_unlock(struct dma_resv *obj)
{
dma_resv_reset_shared_max(obj);
ww_mutex_unlock(&obj->lock);
}
/**
* dma_resv_excl_fence - return the object's exclusive fence
* @obj: the reservation object
*
* Returns the exclusive fence (if any). Caller must either hold the objects
* through dma_resv_lock() or the RCU read side lock through rcu_read_lock(),
* or one of the variants of each
*
* RETURNS
* The exclusive fence or NULL
*/
static inline struct dma_fence *
dma_resv_excl_fence(struct dma_resv *obj)
{
return rcu_dereference_check(obj->fence_excl, dma_resv_held(obj));
}
void dma_resv_init(struct dma_resv *obj);
void dma_resv_fini(struct dma_resv *obj);
int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences);
void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence);
void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
struct dma_fence *fence);
void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence);
int dma_resv_get_fences(struct dma_resv *obj, bool write,
unsigned int *num_fences, struct dma_fence ***fences);
int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
long dma_resv_wait_timeout(struct dma_resv *obj, bool wait_all, bool intr,
unsigned long timeout);
bool dma_resv_test_signaled(struct dma_resv *obj, bool test_all);
void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq);
#endif /* _LINUX_RESERVATION_H */