linux-kernel - [PATCH 4.9 05/32] drm/msm: Unblock writer if reader closes file

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Message-Id: <20190304081602.682608347@linuxfoundation.org>
Date:   Mon,  4 Mar 2019 09:21:53 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        "Kristian H. Kristensen" <hoegsberg@...omium.org>,
        Rob Clark <robdclark@...il.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 05/32] drm/msm: Unblock writer if reader closes file

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 99c66bc051e7407fe0bf0607b142ec0be1a1d1dd ]

Prevents deadlock when fifo is full and reader closes file.

Signed-off-by: Kristian H. Kristensen <hoegsberg@...omium.org>
Signed-off-by: Rob Clark <robdclark@...il.com>
Signed-off-by: Sasha Levin <sashal@...nel.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 8487f461f05f3..4823019eb422b 100644
--- a/drivers/gpu/drm/msm/msm_rd.c
+++ b/drivers/gpu/drm/msm/msm_rd.c
@@ -112,7 +112,9 @@ 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);
@@ -202,7 +204,10 @@ 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