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authorGuennadi Liakhovetski <g.liakhovetski@gmx.de>2012-04-18 06:43:09 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-04-26 11:30:12 -0300
commit2f9a0c880d5c1e159f647950a2eed26618ad2ff1 (patch)
tree99bc40ffdac05c88f97eb5e49afe01c2a85440a9
parente631f578048e2afd8bfede2e9dc86aa4592def3a (diff)
[media] V4L: soc-camera: protect hosts during probing from overzealous user-space
If multiple clients are registered on a single camera host interface, the user-space hot-plug software can try to access the one, that probed first, before probing of the second one has completed. This can be handled by individual host drivers, but it is even better to hold back the user-space until all the probing on this host has completed. This fixes a race on ecovec with two clients registered on the CEU1 host, which otherwise triggers a BUG() in sh_mobile_ceu_remove_device(). Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
-rw-r--r--drivers/media/video/soc_camera.c8
-rw-r--r--include/media/soc_camera.h3
2 files changed, 8 insertions, 3 deletions
diff --git a/drivers/media/video/soc_camera.c b/drivers/media/video/soc_camera.c
index eb25756a07af..aedb970d13f6 100644
--- a/drivers/media/video/soc_camera.c
+++ b/drivers/media/video/soc_camera.c
@@ -530,7 +530,10 @@ static int soc_camera_open(struct file *file)
if (icl->reset)
icl->reset(icd->pdev);
+ /* Don't mess with the host during probe */
+ mutex_lock(&ici->host_lock);
ret = ici->ops->add(icd);
+ mutex_unlock(&ici->host_lock);
if (ret < 0) {
dev_err(icd->pdev, "Couldn't activate the camera: %d\n", ret);
goto eiciadd;
@@ -956,7 +959,7 @@ static void scan_add_host(struct soc_camera_host *ici)
{
struct soc_camera_device *icd;
- mutex_lock(&list_lock);
+ mutex_lock(&ici->host_lock);
list_for_each_entry(icd, &devices, list) {
if (icd->iface == ici->nr) {
@@ -967,7 +970,7 @@ static void scan_add_host(struct soc_camera_host *ici)
}
}
- mutex_unlock(&list_lock);
+ mutex_unlock(&ici->host_lock);
}
#ifdef CONFIG_I2C_BOARDINFO
@@ -1313,6 +1316,7 @@ int soc_camera_host_register(struct soc_camera_host *ici)
list_add_tail(&ici->list, &hosts);
mutex_unlock(&list_lock);
+ mutex_init(&ici->host_lock);
scan_add_host(ici);
return 0;
diff --git a/include/media/soc_camera.h b/include/media/soc_camera.h
index b5c2b6cb0d81..cad374bdcf4b 100644
--- a/include/media/soc_camera.h
+++ b/include/media/soc_camera.h
@@ -59,7 +59,8 @@ struct soc_camera_device {
struct soc_camera_host {
struct v4l2_device v4l2_dev;
struct list_head list;
- unsigned char nr; /* Host number */
+ struct mutex host_lock; /* Protect during probing */
+ unsigned char nr; /* Host number */
void *priv;
const char *drv_name;
struct soc_camera_host_ops *ops;