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| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-03-14 17:07:33 +0300 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-03-14 17:07:33 +0300 |
| commit | b70366e5d31788650b2a5cec5cd13ea80ac7e44a (patch) | |
| tree | d972ffd190111d699200448494fda333d28b2486 /include/linux/ptr_ring.h | |
| parent | f42e181935d5e5670c87d31ae48063a495bbacae (diff) | |
| parent | db6ccf23e8ba40fc2e8914ec9c0eb950df71d9fe (diff) | |
| download | linux-b70366e5d31788650b2a5cec5cd13ea80ac7e44a.tar.xz | |
Merge tag 'doc-4.11-images' of git://git.lwn.net/linux into drm-misc-next
Pointer for Markus's image conversion work.
We need this so we can merge all the pretty drm graphs for 4.12.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Diffstat (limited to 'include/linux/ptr_ring.h')
| -rw-r--r-- | include/linux/ptr_ring.h | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h index 2052011bf9fb..6c70444da3b9 100644 --- a/include/linux/ptr_ring.h +++ b/include/linux/ptr_ring.h @@ -111,6 +111,11 @@ static inline int __ptr_ring_produce(struct ptr_ring *r, void *ptr) return 0; } +/* + * Note: resize (below) nests producer lock within consumer lock, so if you + * consume in interrupt or BH context, you must disable interrupts/BH when + * calling this. + */ static inline int ptr_ring_produce(struct ptr_ring *r, void *ptr) { int ret; @@ -242,6 +247,11 @@ static inline void *__ptr_ring_consume(struct ptr_ring *r) return ptr; } +/* + * Note: resize (below) nests producer lock within consumer lock, so if you + * call this in interrupt or BH context, you must disable interrupts/BH when + * producing. + */ static inline void *ptr_ring_consume(struct ptr_ring *r) { void *ptr; @@ -357,7 +367,7 @@ static inline void **__ptr_ring_swap_queue(struct ptr_ring *r, void **queue, void **old; void *ptr; - while ((ptr = ptr_ring_consume(r))) + while ((ptr = __ptr_ring_consume(r))) if (producer < size) queue[producer++] = ptr; else if (destroy) @@ -372,6 +382,12 @@ static inline void **__ptr_ring_swap_queue(struct ptr_ring *r, void **queue, return old; } +/* + * Note: producer lock is nested within consumer lock, so if you + * resize you must make sure all uses nest correctly. + * In particular if you consume ring in interrupt or BH context, you must + * disable interrupts/BH when doing so. + */ static inline int ptr_ring_resize(struct ptr_ring *r, int size, gfp_t gfp, void (*destroy)(void *)) { @@ -382,17 +398,25 @@ static inline int ptr_ring_resize(struct ptr_ring *r, int size, gfp_t gfp, if (!queue) return -ENOMEM; - spin_lock_irqsave(&(r)->producer_lock, flags); + spin_lock_irqsave(&(r)->consumer_lock, flags); + spin_lock(&(r)->producer_lock); old = __ptr_ring_swap_queue(r, queue, size, gfp, destroy); - spin_unlock_irqrestore(&(r)->producer_lock, flags); + spin_unlock(&(r)->producer_lock); + spin_unlock_irqrestore(&(r)->consumer_lock, flags); kfree(old); return 0; } +/* + * Note: producer lock is nested within consumer lock, so if you + * resize you must make sure all uses nest correctly. + * In particular if you consume ring in interrupt or BH context, you must + * disable interrupts/BH when doing so. + */ static inline int ptr_ring_resize_multiple(struct ptr_ring **rings, int nrings, int size, gfp_t gfp, void (*destroy)(void *)) @@ -412,10 +436,12 @@ static inline int ptr_ring_resize_multiple(struct ptr_ring **rings, int nrings, } for (i = 0; i < nrings; ++i) { - spin_lock_irqsave(&(rings[i])->producer_lock, flags); + spin_lock_irqsave(&(rings[i])->consumer_lock, flags); + spin_lock(&(rings[i])->producer_lock); queues[i] = __ptr_ring_swap_queue(rings[i], queues[i], size, gfp, destroy); - spin_unlock_irqrestore(&(rings[i])->producer_lock, flags); + spin_unlock(&(rings[i])->producer_lock); + spin_unlock_irqrestore(&(rings[i])->consumer_lock, flags); } for (i = 0; i < nrings; ++i) |