drm/vmwgfx: Fix a circular locking dependency bug.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Thomas Hellstrom 2010-02-08 09:57:25 +00:00 committed by Dave Airlie
parent a87897edba
commit 85b9e4878f
3 changed files with 14 additions and 19 deletions

View file

@ -113,6 +113,7 @@ struct vmw_fifo_state {
unsigned long static_buffer_size;
bool using_bounce_buffer;
uint32_t capabilities;
struct mutex fifo_mutex;
struct rw_semaphore rwsem;
};
@ -213,7 +214,7 @@ struct vmw_private {
* Fencing and IRQs.
*/
uint32_t fence_seq;
atomic_t fence_seq;
wait_queue_head_t fence_queue;
wait_queue_head_t fifo_queue;
atomic_t fence_queue_waiters;

View file

@ -74,6 +74,7 @@ int vmw_fifo_init(struct vmw_private *dev_priv, struct vmw_fifo_state *fifo)
fifo->reserved_size = 0;
fifo->using_bounce_buffer = false;
mutex_init(&fifo->fifo_mutex);
init_rwsem(&fifo->rwsem);
/*
@ -117,7 +118,7 @@ int vmw_fifo_init(struct vmw_private *dev_priv, struct vmw_fifo_state *fifo)
(unsigned int) min,
(unsigned int) fifo->capabilities);
dev_priv->fence_seq = dev_priv->last_read_sequence;
atomic_set(&dev_priv->fence_seq, dev_priv->last_read_sequence);
iowrite32(dev_priv->last_read_sequence, fifo_mem + SVGA_FIFO_FENCE);
return vmw_fifo_send_fence(dev_priv, &dummy);
@ -283,7 +284,7 @@ void *vmw_fifo_reserve(struct vmw_private *dev_priv, uint32_t bytes)
uint32_t reserveable = fifo_state->capabilities & SVGA_FIFO_CAP_RESERVE;
int ret;
down_write(&fifo_state->rwsem);
mutex_lock(&fifo_state->fifo_mutex);
max = ioread32(fifo_mem + SVGA_FIFO_MAX);
min = ioread32(fifo_mem + SVGA_FIFO_MIN);
next_cmd = ioread32(fifo_mem + SVGA_FIFO_NEXT_CMD);
@ -351,7 +352,7 @@ void *vmw_fifo_reserve(struct vmw_private *dev_priv, uint32_t bytes)
}
out_err:
fifo_state->reserved_size = 0;
up_write(&fifo_state->rwsem);
mutex_unlock(&fifo_state->fifo_mutex);
return NULL;
}
@ -426,6 +427,7 @@ void vmw_fifo_commit(struct vmw_private *dev_priv, uint32_t bytes)
}
down_write(&fifo_state->rwsem);
if (fifo_state->using_bounce_buffer || reserveable) {
next_cmd += bytes;
if (next_cmd >= max)
@ -437,8 +439,9 @@ void vmw_fifo_commit(struct vmw_private *dev_priv, uint32_t bytes)
if (reserveable)
iowrite32(0, fifo_mem + SVGA_FIFO_RESERVED);
mb();
vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);
up_write(&fifo_state->rwsem);
vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);
mutex_unlock(&fifo_state->fifo_mutex);
}
int vmw_fifo_send_fence(struct vmw_private *dev_priv, uint32_t *sequence)
@ -451,9 +454,7 @@ int vmw_fifo_send_fence(struct vmw_private *dev_priv, uint32_t *sequence)
fm = vmw_fifo_reserve(dev_priv, bytes);
if (unlikely(fm == NULL)) {
down_write(&fifo_state->rwsem);
*sequence = dev_priv->fence_seq;
up_write(&fifo_state->rwsem);
*sequence = atomic_read(&dev_priv->fence_seq);
ret = -ENOMEM;
(void)vmw_fallback_wait(dev_priv, false, true, *sequence,
false, 3*HZ);
@ -461,7 +462,7 @@ int vmw_fifo_send_fence(struct vmw_private *dev_priv, uint32_t *sequence)
}
do {
*sequence = dev_priv->fence_seq++;
*sequence = atomic_add_return(1, &dev_priv->fence_seq);
} while (*sequence == 0);
if (!(fifo_state->capabilities & SVGA_FIFO_CAP_FENCE)) {

View file

@ -84,20 +84,13 @@ bool vmw_fence_signaled(struct vmw_private *dev_priv,
vmw_fifo_idle(dev_priv, sequence))
return true;
/**
* Below is to signal stale fences that have wrapped.
* First, block fence submission.
*/
down_read(&fifo_state->rwsem);
/**
* Then check if the sequence is higher than what we've actually
* emitted. Then the fence is stale and signaled.
*/
ret = ((dev_priv->fence_seq - sequence) > VMW_FENCE_WRAP);
up_read(&fifo_state->rwsem);
ret = ((atomic_read(&dev_priv->fence_seq) - sequence)
> VMW_FENCE_WRAP);
return ret;
}
@ -127,7 +120,7 @@ int vmw_fallback_wait(struct vmw_private *dev_priv,
if (fifo_idle)
down_read(&fifo_state->rwsem);
signal_seq = dev_priv->fence_seq;
signal_seq = atomic_read(&dev_priv->fence_seq);
ret = 0;
for (;;) {