[RFC PATCH 15/26] mx2_emmaprp: remove V4L2_FL_LOCK_ALL_FOPS

[Hans Verkuil]

From: Hans Verkuil <hans.verk...@cisco.com>

Add proper locking to the file operations, allowing for the removal
of the V4L2_FL_LOCK_ALL_FOPS flag.

Signed-off-by: Hans Verkuil <hans.verk...@cisco.com>
---
 drivers/media/video/mx2_emmaprp.c |   28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/drivers/media/video/mx2_emmaprp.c 
b/drivers/media/video/mx2_emmaprp.c
index 0bd5815..c5f6c5c 100644
--- a/drivers/media/video/mx2_emmaprp.c
+++ b/drivers/media/video/mx2_emmaprp.c
@@ -791,11 +791,17 @@ static int emmaprp_open(struct file *file)
        file->private_data = ctx;
        ctx->dev = pcdev;
 
+       if (mutex_lock_interruptible(&pcdev->dev_mutex)) {
+               kfree(ctx);
+               return -ERESTARTSYS;
+       }
+
        ctx->m2m_ctx = v4l2_m2m_ctx_init(pcdev->m2m_dev, ctx, &queue_init);
 
        if (IS_ERR(ctx->m2m_ctx)) {
                int ret = PTR_ERR(ctx->m2m_ctx);
 
+               mutex_unlock(&pcdev->dev_mutex);
                kfree(ctx);
                return ret;
        }
@@ -803,6 +809,7 @@ static int emmaprp_open(struct file *file)
        clk_enable(pcdev->clk_emma);
        ctx->q_data[V4L2_M2M_SRC].fmt = &formats[1];
        ctx->q_data[V4L2_M2M_DST].fmt = &formats[0];
+       mutex_unlock(&pcdev->dev_mutex);
 
        dprintk(pcdev, "Created instance %p, m2m_ctx: %p\n", ctx, ctx->m2m_ctx);
 
@@ -816,8 +823,10 @@ static int emmaprp_release(struct file *file)
 
        dprintk(pcdev, "Releasing instance %p\n", ctx);
 
+       mutex_lock(&pcdev->dev_mutex);
        clk_disable(pcdev->clk_emma);
        v4l2_m2m_ctx_release(ctx->m2m_ctx);
+       mutex_unlock(&pcdev->dev_mutex);
        kfree(ctx);
 
        return 0;
@@ -826,16 +835,27 @@ static int emmaprp_release(struct file *file)
 static unsigned int emmaprp_poll(struct file *file,
                                 struct poll_table_struct *wait)
 {
+       struct emmaprp_dev *pcdev = video_drvdata(file);
        struct emmaprp_ctx *ctx = file->private_data;
+       unsigned int res;
 
-       return v4l2_m2m_poll(file, ctx->m2m_ctx, wait);
+       mutex_lock(&pcdev->dev_mutex);
+       res = v4l2_m2m_poll(file, ctx->m2m_ctx, wait);
+       mutex_unlock(&pcdev->dev_mutex);
+       return res;
 }
 
 static int emmaprp_mmap(struct file *file, struct vm_area_struct *vma)
 {
+       struct emmaprp_dev *pcdev = video_drvdata(file);
        struct emmaprp_ctx *ctx = file->private_data;
+       int ret;
 
-       return v4l2_m2m_mmap(file, ctx->m2m_ctx, vma);
+       if (mutex_lock_interruptible(&pcdev->dev_mutex))
+               return -ERESTARTSYS;
+       ret = v4l2_m2m_mmap(file, ctx->m2m_ctx, vma);
+       mutex_unlock(&pcdev->dev_mutex);
+       return ret;
 }
 
 static const struct v4l2_file_operations emmaprp_fops = {
@@ -904,10 +924,6 @@ static int emmaprp_probe(struct platform_device *pdev)
        }
 
        *vfd = emmaprp_videodev;
-       /* Locking in file operations other than ioctl should be done
-          by the driver, not the V4L2 core.
-          This driver needs auditing so that this flag can be removed. */
-       set_bit(V4L2_FL_LOCK_ALL_FOPS, &vfd->flags);
        vfd->lock = &pcdev->dev_mutex;
 
        video_set_drvdata(vfd, pcdev);
-- 
1.7.10

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