drm/vmwgfx: Fix a circular locking dependency bug.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 3e4e670d32169c791bae9e479779e3e0ca706bc2..356dc935ec133f974c2c95e2be5d1146cd07c9a9 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -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;

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
index 4157547cc6e44a79570d74004713ba187acc1c99..39d43a01d846fd9e7bcd6a1206b06143f90a740d 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
@@ -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)) {

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c b/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c
index d40086fc8647abb3f293cd7d9f0baeb31b254db3..4d7cb539386000b50798960f8615d2fc2b25d2ba 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c
@@ -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 (;;) {