Op 25-10-12 09:42, Thomas Hellstrom schreef:

On 10/12/2012 04:58 PM, Maarten Lankhorst wrote:

...

Signed-off-by: Maarten Lankhorst maarten.lankhorst@canonical.com

drivers/gpu/drm/ttm/ttm_bo.c | 12 ++++++------ include/drm/ttm/ttm_bo_api.h | 14 ++++++++++++++ 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index be1148e..d9d8541 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -161,9 +161,9 @@ int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo, bool interruptible) { if (interruptible) { return wait_event_interruptible(bo->event_queue,

•                       atomic_read(&bo->reserved) == 0);
  

•                       !ttm_bo_is_reserved(bo));
  } else {
  

•    wait_event(bo->event_queue, atomic_read(&bo->reserved) == 0);
  

•    wait_event(bo->event_queue, !ttm_bo_is_reserved(bo));
      return 0;
  }
  

  }

@@ -174,7 +174,7 @@ void ttm_bo_add_to_lru(struct ttm_buffer_object *bo) struct ttm_bo_device *bdev = bo->bdev; struct ttm_mem_type_manager *man;

• BUG_ON(!atomic_read(&bo->reserved));

• BUG_ON(!ttm_bo_is_reserved(bo)); if (!(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) { @@ -748,7 +748,7 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bool interruptible, goto out; }
  • BUG_ON(!atomic_read(&bo->reserved));
• BUG_ON(!ttm_bo_is_reserved(bo)); evict_mem = bo->mem; evict_mem.mm_node = NULL;

@@ -1058,7 +1058,7 @@ int ttm_bo_move_buffer(struct ttm_buffer_object *bo, struct ttm_mem_reg mem; struct ttm_bo_device *bdev = bo->bdev;

• BUG_ON(!atomic_read(&bo->reserved));

• BUG_ON(!ttm_bo_is_reserved(bo)); /*
  • FIXME: It's possible to pipeline buffer moves.

@@ -1115,7 +1115,7 @@ int ttm_bo_validate(struct ttm_buffer_object *bo, { int ret;

• BUG_ON(!atomic_read(&bo->reserved));

• BUG_ON(!ttm_bo_is_reserved(bo)); /* Check that range is valid */ if (placement->lpfn || placement->fpfn) if (placement->fpfn > placement->lpfn ||

diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h index 9654451..1d71f6b 100644 --- a/include/drm/ttm/ttm_bo_api.h +++ b/include/drm/ttm/ttm_bo_api.h @@ -705,4 +705,18 @@ extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp, extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev); +/**

• • ttm_bo_is_reserved - return an indication if a ttm buffer object is reserved
• • @bo: The buffer object to check.
• • This function returns an indication if a bo is reserved or not, and should
• • only be used to print an error when it is not from incorrect api usage, since
• • there's no guarantee that it is the caller that is holding the reservation.
• */

+static inline bool ttm_bo_is_reserved(struct ttm_buffer_object *bo) +{

• return atomic_read(&bo->reserved);

+}

• #endif

This looks good, although for clarity we should add in the comments that if the caller is holding the reservation, the function is guaranteed to return true.

Otherwise Reviewed-by: Thomas Hellstrom thellstrom@vmware.com

Unless you use lockdep, you can't say with 100% certainty if the CALLER is holding it or not. :-) But lockdep can actually check if that's the case with lockdep_is_held(&ttm->reservation_lock); which iterates over all locks held by the current task.

~Maarten

Updated version with a comment about return value in ttm_bo_is_reserved:

drm/ttm: Add ttm_bo_is_reserved function

Signed-off-by: Maarten Lankhorst maarten.lankhorst@canonical.com Reviewed-by: Thomas Hellstrom thellstrom@vmware.com

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 2b3f69b..82e2633 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -162,9 +162,9 @@ int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo, bool interruptible) { if (interruptible) { return wait_event_interruptible(bo->event_queue, - atomic_read(&bo->reserved) == 0); + !ttm_bo_is_reserved(bo)); } else { - wait_event(bo->event_queue, atomic_read(&bo->reserved) == 0); + wait_event(bo->event_queue, !ttm_bo_is_reserved(bo)); return 0; } } @@ -175,7 +175,7 @@ void ttm_bo_add_to_lru(struct ttm_buffer_object *bo) struct ttm_bo_device *bdev = bo->bdev; struct ttm_mem_type_manager *man;

- BUG_ON(!atomic_read(&bo->reserved)); + BUG_ON(!ttm_bo_is_reserved(bo));

if (!(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) {

@@ -756,7 +756,7 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bool interruptible, goto out; }

- BUG_ON(!atomic_read(&bo->reserved)); + BUG_ON(!ttm_bo_is_reserved(bo));

evict_mem = bo->mem; evict_mem.mm_node = NULL; @@ -1063,7 +1063,7 @@ int ttm_bo_move_buffer(struct ttm_buffer_object *bo, struct ttm_mem_reg mem; struct ttm_bo_device *bdev = bo->bdev;

- BUG_ON(!atomic_read(&bo->reserved)); + BUG_ON(!ttm_bo_is_reserved(bo));

/* * FIXME: It's possible to pipeline buffer moves. @@ -1120,7 +1120,7 @@ int ttm_bo_validate(struct ttm_buffer_object *bo, { int ret;

- BUG_ON(!atomic_read(&bo->reserved)); + BUG_ON(!ttm_bo_is_reserved(bo)); /* Check that range is valid */ if (placement->lpfn || placement->fpfn) if (placement->fpfn > placement->lpfn || diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h index 850424f..7a5b574 100644 --- a/include/drm/ttm/ttm_bo_api.h +++ b/include/drm/ttm/ttm_bo_api.h @@ -737,4 +737,20 @@ extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,

extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev);

+/** + * ttm_bo_is_reserved - return an indication if a ttm buffer object is reserved + * + * @bo: The buffer object to check. + * + * This function returns an indication if a bo is reserved or not, and should + * only be used to print an error when it is not from incorrect api usage, since + * there's no guarantee that it is the caller that is holding the reservation. + * + * Returns true if reserved, false if unreserved. + */ +static inline bool ttm_bo_is_reserved(struct ttm_buffer_object *bo) +{ + return atomic_read(&bo->reserved); +} + #endif