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@xxxxxx> --- Mauro, since this fixes a race, present in the current kernel, I'll push it for 3.4 later. Or you can just pick it up from this mail - I don't have any more pending fixes atm. drivers/media/video/soc_camera.c | 8 ++++++-- include/media/soc_camera.h | 3 ++- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/media/video/soc_camera.c b/drivers/media/video/soc_camera.c index eb25756..aedb970 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 b5c2b6c..cad374b 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; -- 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html