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drm/ttm: add ttm_bo_is_reserved

PATCH In review Maarten Lankhorst 2 participants 3 messages Oct 12, 2012 – Nov 6, 2012

Subsystems (3)
DRM drivers DRM misc DRM TTM
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Maarten Lankhorst

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#0 lore raw

PATCH 1/3 drm/ttm: add ttm_bo_is_reserved

Signed-off-by Maarten Lankhorst <[email protected]>
---
 drivers/gpu/drm/ttm/ttm_bo.c |   12 ++++++------
 include/drm/ttm/ttm_bo_api.h |   14 ++++++++++++++
 2 files changed, 20 insertions(+), 6 deletions(-)
drivers/gpu/drm/ttm/ttm_bo.c +6 -6
index be1148e..d9d8541 100644
@@ -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 ||
include/drm/ttm/ttm_bo_api.h +14 -0
index 9654451..1d71f6b 100644
@@ -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
Reviewed-by on v1 1/3
#1 lore raw
Quoted 71 lines · Maarten Lankhorst
Signed-off-by Maarten Lankhorst <[email protected]>
---
  drivers/gpu/drm/ttm/ttm_bo.c |   12 ++++++------
  include/drm/ttm/ttm_bo_api.h |   14 ++++++++++++++
  2 files changed, 20 insertions(+), 6 deletions(-)
drivers/gpu/drm/ttm/ttm_bo.c +6 -6
index be1148e..d9d8541 100644
@@ -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 ||
include/drm/ttm/ttm_bo_api.h +5 -0
index 9654451..1d71f6b 100644
@@ -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.
+ *

include/drm/ttm/ttm_bo_api.h extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp, · line 722

Quoted 10 lines
include/drm/ttm/ttm_bo_api.h +9 -0
+ * 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 <[email protected]>
Quoted 5 lines

_______________________________________________
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author Reviewed-by Thomas Hellstrom
#2 lore raw

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

Quoted 75 lines · Maarten Lankhorst
Quoted 61 lines
Signed-off-by Maarten Lankhorst <[email protected]>
---
  drivers/gpu/drm/ttm/ttm_bo.c |   12 ++++++------
  include/drm/ttm/ttm_bo_api.h |   14 ++++++++++++++
  2 files changed, 20 insertions(+), 6 deletions(-)
drivers/gpu/drm/ttm/ttm_bo.c +6 -2
index be1148e..d9d8541 100644
@@ -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 ||
include/drm/ttm/ttm_bo_api.h +4 -0
index 9654451..1d71f6b 100644
@@ -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.
+ *

include/drm/ttm/ttm_bo_api.h extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp, · line 720

Quoted 10 lines
include/drm/ttm/ttm_bo_api.h +9 -0
+ * 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.

Quoted 2 lines

Otherwise

Reviewed-by Thomas Hellstrom <[email protected]>

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 <[email protected]>
Reviewed-by Thomas Hellstrom <[email protected]>
drivers/gpu/drm/ttm/ttm_bo.c +6 -6
index 2b3f69b..82e2633 100644
@@ -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 ||
include/drm/ttm/ttm_bo_api.h +16 -0
index 850424f..7a5b574 100644
@@ -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