[PATCH] drm/msm: use proper memory barriers for updating tail/head
Rob Clark
robdclark at gmail.com
Mon Oct 2 14:37:11 UTC 2017
Fixes intermittent corruption of cmdstream dump.
Signed-off-by: Rob Clark <robdclark at gmail.com>
---
drivers/gpu/drm/msm/msm_rd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_rd.c b/drivers/gpu/drm/msm/msm_rd.c
index 5c087a4228ff..918c65e19964 100644
--- a/drivers/gpu/drm/msm/msm_rd.c
+++ b/drivers/gpu/drm/msm/msm_rd.c
@@ -120,7 +120,7 @@ static void rd_write(struct msm_rd_state *rd, const void *buf, int sz)
n = min(sz, circ_space_to_end(&rd->fifo));
memcpy(fptr, ptr, n);
- fifo->head = (fifo->head + n) & (BUF_SZ - 1);
+ smp_store_release(&fifo->head, (fifo->head + n) & (BUF_SZ - 1));
sz -= n;
ptr += n;
@@ -157,7 +157,7 @@ static ssize_t rd_read(struct file *file, char __user *buf,
goto out;
}
- fifo->tail = (fifo->tail + n) & (BUF_SZ - 1);
+ smp_store_release(&fifo->tail, (fifo->tail + n) & (BUF_SZ - 1));
*ppos += n;
wake_up_all(&rd->fifo_event);
--
2.13.5
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