[PATCH AUTOSEL 4.4 01/20] drm/msm: Unblock writer if reader closes file

Sasha Levin
2019-02-15T02:20:42Z

From: "Kristian H. Kristensen" <hoegsberg@gmail.com>

[ Upstream commit 99c66bc051e7407fe0bf0607b142ec0be1a1d1dd ]

Prevents deadlock when fifo is full and reader closes file.

Signed-off-by: Kristian H. Kristensen <hoegsberg@chromium.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/msm/msm_rd.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/msm_rd.c b/drivers/gpu/drm/msm/msm_rd.c
index 9a78c48817c6..909a52b21ebe 100644
--- a/drivers/gpu/drm/msm/msm_rd.c
+++ b/drivers/gpu/drm/msm/msm_rd.c
@@ -103,7 +103,9 @@ static void rd_write(struct msm_rd_state *rd, const void *buf, int sz)
char *fptr = &fifo->buf[fifo->head];
int n;

- wait_event(rd->fifo_event, circ_space(&rd->fifo) > 0);
+ wait_event(rd->fifo_event, circ_space(&rd->fifo) > 0 || !rd->open);
+ if (!rd->open)
+ return;

n = min(sz, circ_space_to_end(&rd->fifo));
memcpy(fptr, ptr, n);
@@ -192,7 +194,10 @@ static int rd_open(struct inode *inode, struct file *file)
static int rd_release(struct inode *inode, struct file *file)
{
struct msm_rd_state *rd = inode->i_private;
+
rd->open = false;
+ wake_up_all(&rd->fifo_event);
+
return 0;
}

--
2.19.1