diff options
| author | Ian Forbes <ian.forbes@broadcom.com> | 2025-05-30 13:35:08 -0500 |
|---|---|---|
| committer | Zack Rusin <zack.rusin@broadcom.com> | 2025-06-17 22:49:31 -0400 |
| commit | c82f55f4aa57bf5ba412d55856fe50514b47b971 (patch) | |
| tree | d3ed4789760119f211eaf2a9f096f59f0efee154 /drivers/gpu/drm/vmwgfx/vmwgfx_irq.c | |
| parent | a72002cb181f350734108228b24c5d10d358f95a (diff) | |
drm/vmwgfx: Update last_read_seqno under the fence lock
There was a possible race in vmw_update_seqno. Because of this race it
was possible for last_read_seqno to go backwards. Remove this function
and replace it with vmw_update_fences which now sets and returns the
last_read_seqno while holding the fence lock. This serialization via the
fence lock ensures that last_read_seqno is monotonic again.
Signed-off-by: Ian Forbes <ian.forbes@broadcom.com>
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Link: https://lore.kernel.org/r/20250530183510.733175-1-ian.forbes@broadcom.com
Diffstat (limited to 'drivers/gpu/drm/vmwgfx/vmwgfx_irq.c')
| -rw-r--r-- | drivers/gpu/drm/vmwgfx/vmwgfx_irq.c | 17 |
1 files changed, 4 insertions, 13 deletions
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c b/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c index 086e69a130d4..592cd78e10e0 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c @@ -123,26 +123,17 @@ static bool vmw_fifo_idle(struct vmw_private *dev_priv, uint32_t seqno) return (vmw_read(dev_priv, SVGA_REG_BUSY) == 0); } -void vmw_update_seqno(struct vmw_private *dev_priv) -{ - uint32_t seqno = vmw_fence_read(dev_priv); - - if (dev_priv->last_read_seqno != seqno) { - dev_priv->last_read_seqno = seqno; - vmw_fences_update(dev_priv->fman); - } -} - bool vmw_seqno_passed(struct vmw_private *dev_priv, uint32_t seqno) { bool ret; + u32 last_read_seqno = atomic_read_acquire(&dev_priv->last_read_seqno); - if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP)) + if (last_read_seqno - seqno < VMW_FENCE_WRAP) return true; - vmw_update_seqno(dev_priv); - if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP)) + last_read_seqno = vmw_fences_update(dev_priv->fman); + if (last_read_seqno - seqno < VMW_FENCE_WRAP) return true; if (!vmw_has_fences(dev_priv) && vmw_fifo_idle(dev_priv, seqno)) |