From 7bc80a5462c37eab58a9ea386064307c0f447fd1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20K=C3=B6nig?= Date: Tue, 9 Nov 2021 11:08:18 +0100 Subject: dma-buf: add enum dma_resv_usage v4 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This change adds the dma_resv_usage enum and allows us to specify why a dma_resv object is queried for its containing fences. Additional to that a dma_resv_usage_rw() helper function is added to aid retrieving the fences for a read or write userspace submission. This is then deployed to the different query functions of the dma_resv object and all of their users. When the write paratermer was previously true we now use DMA_RESV_USAGE_WRITE and DMA_RESV_USAGE_READ otherwise. v2: add KERNEL/OTHER in separate patch v3: some kerneldoc suggestions by Daniel v4: some more kerneldoc suggestions by Daniel, fix missing cases lost in the rebase pointed out by Bas. Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-2-christian.koenig@amd.com --- include/linux/dma-buf.h | 8 ++++-- include/linux/dma-resv.h | 73 +++++++++++++++++++++++++++++++++++++++--------- 2 files changed, 66 insertions(+), 15 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 6fb91956ab8d..a297397743a2 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -408,6 +408,9 @@ struct dma_buf { * pipelining across drivers. These do not set any fences for their * access. An example here is v4l. * + * - Driver should use dma_resv_usage_rw() when retrieving fences as + * dependency for implicit synchronization. + * * DYNAMIC IMPORTER RULES: * * Dynamic importers, see dma_buf_attachment_is_dynamic(), have @@ -423,8 +426,9 @@ struct dma_buf { * * IMPORTANT: * - * All drivers must obey the struct dma_resv rules, specifically the - * rules for updating and obeying fences. + * All drivers and memory management related functions must obey the + * struct dma_resv rules, specifically the rules for updating and + * obeying fences. See enum dma_resv_usage for further descriptions. */ struct dma_resv *resv; diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 5fa04d0fccad..92cd8023980f 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -49,6 +49,53 @@ extern struct ww_class reservation_ww_class; struct dma_resv_list; +/** + * enum dma_resv_usage - how the fences from a dma_resv obj are used + * + * This enum describes the different use cases for a dma_resv object and + * controls which fences are returned when queried. + * + * An important fact is that there is the order WRITEobj = obj; - cursor->all_fences = all_fences; + cursor->usage = usage; cursor->fence = NULL; } @@ -241,7 +288,7 @@ static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *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 + * @usage: controls which fences to return * @fence: the current fence * * Iterate over the fences in a struct dma_resv object while holding the @@ -250,8 +297,8 @@ static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *cursor) * 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), \ +#define dma_resv_for_each_fence(cursor, obj, usage, fence) \ + for (dma_resv_iter_begin(cursor, obj, usage), \ fence = dma_resv_iter_first(cursor); fence; \ fence = dma_resv_iter_next(cursor)) @@ -418,14 +465,14 @@ 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, +int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage, unsigned int *num_fences, struct dma_fence ***fences); -int dma_resv_get_singleton(struct dma_resv *obj, bool write, +int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage, struct dma_fence **fence); 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); +long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage, + bool intr, unsigned long timeout); +bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage); void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq); #endif /* _LINUX_RESERVATION_H */ -- cgit v1.2.3 From 73511edf8b196e6f1ccda0fdf294ff57aa2dc9db Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20K=C3=B6nig?= Date: Tue, 9 Nov 2021 11:08:18 +0100 Subject: dma-buf: specify usage while adding fences to dma_resv obj v7 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Instead of distingting between shared and exclusive fences specify the fence usage while adding fences. Rework all drivers to use this interface instead and deprecate the old one. v2: some kerneldoc comments suggested by Daniel v3: fix a missing case in radeon v4: rebase on nouveau changes, fix lockdep and temporary disable warning v5: more documentation updates v6: separate internal dma_resv changes from this patch, avoids to disable warning temporary, rebase on upstream changes v7: fix missed case in lima driver, minimize changes to i915_gem_busy_ioctl Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-3-christian.koenig@amd.com --- include/linux/dma-buf.h | 16 ++++++++-------- include/linux/dma-resv.h | 25 +++++++++++++++---------- 2 files changed, 23 insertions(+), 18 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index a297397743a2..71731796c8c3 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -393,15 +393,15 @@ struct dma_buf { * e.g. exposed in `Implicit Fence Poll Support`_ must follow the * below rules. * - * - Drivers must add a shared fence through dma_resv_add_shared_fence() - * for anything the userspace API considers a read access. This highly - * depends upon the API and window system. + * - Drivers must add a read fence through dma_resv_add_fence() with the + * DMA_RESV_USAGE_READ flag for anything the userspace API considers a + * read access. This highly depends upon the API and window system. * - * - Similarly drivers must set the exclusive fence through - * dma_resv_add_excl_fence() for anything the userspace API considers - * write access. + * - Similarly drivers must add a write fence through + * dma_resv_add_fence() with the DMA_RESV_USAGE_WRITE flag for + * anything the userspace API considers write access. * - * - Drivers may just always set the exclusive fence, since that only + * - Drivers may just always add a write fence, since that only * causes unecessarily synchronization, but no correctness issues. * * - Some drivers only expose a synchronous userspace API with no @@ -416,7 +416,7 @@ struct dma_buf { * Dynamic importers, see dma_buf_attachment_is_dynamic(), have * additional constraints on how they set up fences: * - * - Dynamic importers must obey the exclusive fence and wait for it to + * - Dynamic importers must obey the write fences and wait for them to * signal before allowing access to the buffer's underlying storage * through the device. * diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 92cd8023980f..98dc5234b487 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -195,6 +195,9 @@ struct dma_resv_iter { /** @fence: the currently handled fence */ struct dma_fence *fence; + /** @fence_usage: the usage of the current fence */ + enum dma_resv_usage fence_usage; + /** @seq: sequence number to check for modifications */ unsigned int seq; @@ -244,14 +247,15 @@ static inline void dma_resv_iter_end(struct dma_resv_iter *cursor) } /** - * dma_resv_iter_is_exclusive - test if the current fence is the exclusive one + * dma_resv_iter_usage - Return the usage of the current fence * @cursor: the cursor of the current position * - * Returns true if the currently returned fence is the exclusive one. + * Returns the usage of the currently processed fence. */ -static inline bool dma_resv_iter_is_exclusive(struct dma_resv_iter *cursor) +static inline enum dma_resv_usage +dma_resv_iter_usage(struct dma_resv_iter *cursor) { - return cursor->index == 0; + return cursor->fence_usage; } /** @@ -306,9 +310,9 @@ static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *cursor) #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); +void dma_resv_reset_max_fences(struct dma_resv *obj); #else -static inline void dma_resv_reset_shared_max(struct dma_resv *obj) {} +static inline void dma_resv_reset_max_fences(struct dma_resv *obj) {} #endif /** @@ -454,17 +458,18 @@ static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj) */ static inline void dma_resv_unlock(struct dma_resv *obj) { - dma_resv_reset_shared_max(obj); + dma_resv_reset_max_fences(obj); ww_mutex_unlock(&obj->lock); } void dma_resv_init(struct dma_resv *obj); void dma_resv_fini(struct dma_resv *obj); int dma_resv_reserve_fences(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_add_fence(struct dma_resv *obj, struct dma_fence *fence, + enum dma_resv_usage usage); 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); + struct dma_fence *fence, + enum dma_resv_usage usage); int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage, unsigned int *num_fences, struct dma_fence ***fences); int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage, -- cgit v1.2.3 From 047a1b877ed48098bed71fcfb1d4891e1b54441d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20K=C3=B6nig?= Date: Tue, 23 Nov 2021 09:33:07 +0100 Subject: dma-buf & drm/amdgpu: remove dma_resv workaround MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Rework the internals of the dma_resv object to allow adding more than one write fence and remember for each fence what purpose it had. This allows removing the workaround from amdgpu which used a container for this instead. Signed-off-by: Christian König Reviewed-by: Daniel Vetter Cc: amd-gfx@lists.freedesktop.org Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-4-christian.koenig@amd.com --- include/linux/dma-resv.h | 47 +++++++++++------------------------------------ 1 file changed, 11 insertions(+), 36 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 98dc5234b487..7bb7e7edbb6f 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -99,8 +99,8 @@ static inline enum dma_resv_usage dma_resv_usage_rw(bool write) /** * struct dma_resv - a reservation object manages fences for a buffer * - * There are multiple uses for this, with sometimes slightly different rules in - * how the fence slots are used. + * This is a container for dma_fence objects which needs to handle multiple use + * cases. * * 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 @@ -130,47 +130,22 @@ struct dma_resv { * @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. + * read-only access to @fences while ensuring we take a consistent + * snapshot. */ seqcount_ww_mutex_t seq; /** - * @fence_excl: + * @fences: * - * The exclusive fence, if there is one currently. + * Array of fences which where added to the dma_resv object * - * 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. - * - * 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_fence __rcu *fence_excl; - - /** - * @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 + * A new fence is added by calling dma_resv_add_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_fences(). - * - * 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_list __rcu *fences; }; /** @@ -207,8 +182,8 @@ struct dma_resv_iter { /** @fences: the shared fences; private, *MUST* not dereference */ struct dma_resv_list *fences; - /** @shared_count: number of shared fences */ - unsigned int shared_count; + /** @num_fences: number of fences */ + unsigned int num_fences; /** @is_restarted: true if this is the first returned fence */ bool is_restarted; -- cgit v1.2.3 From b29895e18304feb7e8afc6388db7ece60327b23c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20K=C3=B6nig?= Date: Fri, 26 Nov 2021 14:12:42 +0100 Subject: dma-buf: add DMA_RESV_USAGE_KERNEL v3 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add an usage for kernel submissions. Waiting for those are mandatory for dynamic DMA-bufs. As a precaution this patch also changes all occurrences where fences are added as part of memory management in TTM, VMWGFX and i915 to use the new value because it now becomes possible for drivers to ignore fences with the WRITE usage. v2: use "must" in documentation, fix whitespaces v3: separate out some driver changes and better document why some changes should still be part of this patch. Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-5-christian.koenig@amd.com --- include/linux/dma-resv.h | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 7bb7e7edbb6f..a749f229ae91 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -55,11 +55,29 @@ struct dma_resv_list; * This enum describes the different use cases for a dma_resv object and * controls which fences are returned when queried. * - * An important fact is that there is the order WRITE Date: Tue, 9 Nov 2021 11:08:18 +0100 Subject: dma-buf: add DMA_RESV_USAGE_BOOKKEEP v3 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add an usage for submissions independent of implicit sync but still interesting for memory management. v2: cleanup the kerneldoc a bit v3: separate amdgpu changes from this Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-10-christian.koenig@amd.com --- include/linux/dma-resv.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index a749f229ae91..1db759eacc98 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -55,7 +55,7 @@ struct dma_resv_list; * This enum describes the different use cases for a dma_resv object and * controls which fences are returned when queried. * - * An important fact is that there is the order KERNEL Date: Mon, 4 Apr 2022 14:58:37 +0200 Subject: dma-buf: drop seq count based update MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This should be possible now since we don't have the distinction between exclusive and shared fences any more. The only possible pitfall is that a dma_fence would be reused during the RCU grace period, but even that could be handled with a single extra check. Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-15-christian.koenig@amd.com --- include/linux/dma-resv.h | 12 ------------ 1 file changed, 12 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 1db759eacc98..c8ccbc94d5d2 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -155,15 +155,6 @@ struct dma_resv { */ struct ww_mutex lock; - /** - * @seq: - * - * Sequence count for managing RCU read-side synchronization, allows - * read-only access to @fences while ensuring we take a consistent - * snapshot. - */ - seqcount_ww_mutex_t seq; - /** * @fences: * @@ -202,9 +193,6 @@ struct dma_resv_iter { /** @fence_usage: the usage of the current fence */ enum dma_resv_usage fence_usage; - /** @seq: sequence number to check for modifications */ - unsigned int seq; - /** @index: index into the shared fences */ unsigned int index; -- cgit v1.2.3 From e84815cbbc767617221e6891e77f2486c9199dfa Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20K=C3=B6nig?= Date: Thu, 7 Apr 2022 10:20:55 +0200 Subject: seqlock: drop seqcount_ww_mutex_t MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Daniel pointed out that this series removes the last user of seqcount_ww_mutex_t, so let's drop this. Signed-off-by: Christian König Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Cc: Waiman Long Cc: Boqun Feng Cc: linux-kernel@vger.kernel.org Acked-by: Peter Zijlstra (Intel) Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-16-christian.koenig@amd.com --- include/linux/seqlock.h | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h index 37ded6b8fee6..3926e9027947 100644 --- a/include/linux/seqlock.h +++ b/include/linux/seqlock.h @@ -17,7 +17,6 @@ #include #include #include -#include #include #include @@ -164,7 +163,7 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s) * static initializer or init function. This enables lockdep to validate * that the write side critical section is properly serialized. * - * LOCKNAME: raw_spinlock, spinlock, rwlock, mutex, or ww_mutex. + * LOCKNAME: raw_spinlock, spinlock, rwlock or mutex */ /* @@ -184,7 +183,6 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s) #define seqcount_spinlock_init(s, lock) seqcount_LOCKNAME_init(s, lock, spinlock) #define seqcount_rwlock_init(s, lock) seqcount_LOCKNAME_init(s, lock, rwlock) #define seqcount_mutex_init(s, lock) seqcount_LOCKNAME_init(s, lock, mutex) -#define seqcount_ww_mutex_init(s, lock) seqcount_LOCKNAME_init(s, lock, ww_mutex) /* * SEQCOUNT_LOCKNAME() - Instantiate seqcount_LOCKNAME_t and helpers @@ -277,7 +275,6 @@ SEQCOUNT_LOCKNAME(raw_spinlock, raw_spinlock_t, false, s->lock, raw_s SEQCOUNT_LOCKNAME(spinlock, spinlock_t, __SEQ_RT, s->lock, spin, spin_lock(s->lock)) SEQCOUNT_LOCKNAME(rwlock, rwlock_t, __SEQ_RT, s->lock, read, read_lock(s->lock)) SEQCOUNT_LOCKNAME(mutex, struct mutex, true, s->lock, mutex, mutex_lock(s->lock)) -SEQCOUNT_LOCKNAME(ww_mutex, struct ww_mutex, true, &s->lock->base, ww_mutex, ww_mutex_lock(s->lock, NULL)) /* * SEQCNT_LOCKNAME_ZERO - static initializer for seqcount_LOCKNAME_t @@ -304,8 +301,7 @@ SEQCOUNT_LOCKNAME(ww_mutex, struct ww_mutex, true, &s->lock->base, ww_mu __seqprop_case((s), raw_spinlock, prop), \ __seqprop_case((s), spinlock, prop), \ __seqprop_case((s), rwlock, prop), \ - __seqprop_case((s), mutex, prop), \ - __seqprop_case((s), ww_mutex, prop)) + __seqprop_case((s), mutex, prop)) #define seqprop_ptr(s) __seqprop(s, ptr) #define seqprop_sequence(s) __seqprop(s, sequence) -- cgit v1.2.3 From 6b2060cf9138a2cd5f3468a949d3869abed049ef Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Tue, 5 Apr 2022 23:03:26 +0200 Subject: fb: Delete fb_info->queue It was only used by fbcon, and that now switched to its own, private work. Acked-by: Sam Ravnborg Acked-by: Thomas Zimmermann Signed-off-by: Daniel Vetter Cc: Helge Deller Cc: linux-fbdev@vger.kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20220405210335.3434130-9-daniel.vetter@ffwll.ch --- include/linux/fb.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/fb.h b/include/linux/fb.h index 9a77ab615c36..f95da1af9ff6 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -450,7 +450,6 @@ struct fb_info { struct fb_var_screeninfo var; /* Current var */ struct fb_fix_screeninfo fix; /* Current fix */ struct fb_monspecs monspecs; /* Current Monitor specs */ - struct work_struct queue; /* Framebuffer event queue */ struct fb_pixmap pixmap; /* Image hardware mapper */ struct fb_pixmap sprite; /* Cursor hardware mapper */ struct fb_cmap cmap; /* Current cmap */ -- cgit v1.2.3