[media] saa7146: remove V4L2_FL_LOCK_ALL_FOPS

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

I also removed some dead code in the form of the saa7146_devices list and
saa7146_devices_lock mutex: these were used once but that was a long time
ago.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

2 files changed, 39 insertions, 24 deletions

diff --git a/drivers/media/common/saa7146_core.c b/drivers/media/common/saa7146_core.c
index d6b1cf66042d..bb6ee5191eb1 100644
--- a/drivers/media/common/saa7146_core.c
+++ b/drivers/media/common/saa7146_core.c
@@ -23,9 +23,6 @@
 #include <media/saa7146.h>
 #include <linux/module.h>
 
-LIST_HEAD(saa7146_devices);
-DEFINE_MUTEX(saa7146_devices_lock);
-
 static int saa7146_num;
 
 unsigned int saa7146_debug;
@@ -482,8 +479,6 @@ static int saa7146_init_one(struct pci_dev *pci, const struct pci_device_id *ent
            set it explicitly. */
         pci_set_drvdata(pci, &dev->v4l2_dev);
 
-        INIT_LIST_HEAD(&dev->item);
-        list_add_tail(&dev->item,&saa7146_devices);
         saa7146_num++;
 
         err = 0;
@@ -545,7 +540,6 @@ static void saa7146_remove_one(struct pci_dev *pdev)
 
         iounmap(dev->mem);
         pci_release_region(pdev, 0);
-        list_del(&dev->item);
         pci_disable_device(pdev);
         kfree(dev);
 
@@ -592,8 +586,6 @@ EXPORT_SYMBOL_GPL(saa7146_setgpio);
 EXPORT_SYMBOL_GPL(saa7146_i2c_adapter_prepare);
 
 EXPORT_SYMBOL_GPL(saa7146_debug);
-EXPORT_SYMBOL_GPL(saa7146_devices);
-EXPORT_SYMBOL_GPL(saa7146_devices_lock);
 
 MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
 MODULE_DESCRIPTION("driver for generic saa7146-based hardware");
diff --git a/drivers/media/common/saa7146_fops.c b/drivers/media/common/saa7146_fops.c
index 0cdbd742974a..b3890bd49df6 100644
--- a/drivers/media/common/saa7146_fops.c
+++ b/drivers/media/common/saa7146_fops.c
@@ -201,7 +201,7 @@ static int fops_open(struct file *file)
 
         DEB_EE("file:%p, dev:%s\n", file, video_device_node_name(vdev));
 
-        if (mutex_lock_interruptible(&saa7146_devices_lock))
+        if (mutex_lock_interruptible(vdev->lock))
                 return -ERESTARTSYS;
 
         DEB_D("using: %p\n", dev);
@@ -253,7 +253,7 @@ out:
                 kfree(fh);
                 file->private_data = NULL;
         }
-        mutex_unlock(&saa7146_devices_lock);
+        mutex_unlock(vdev->lock);
         return result;
 }
 
@@ -265,7 +265,7 @@ static int fops_release(struct file *file)
 
         DEB_EE("file:%p\n", file);
 
-        if (mutex_lock_interruptible(&saa7146_devices_lock))
+        if (mutex_lock_interruptible(vdev->lock))
                 return -ERESTARTSYS;
 
         if (vdev->vfl_type == VFL_TYPE_VBI) {
@@ -283,7 +283,7 @@ static int fops_release(struct file *file)
         file->private_data = NULL;
         kfree(fh);
 
-        mutex_unlock(&saa7146_devices_lock);
+        mutex_unlock(vdev->lock);
 
         return 0;
 }
@@ -293,6 +293,7 @@ static int fops_mmap(struct file *file, struct vm_area_struct * vma)
         struct video_device *vdev = video_devdata(file);
         struct saa7146_fh *fh = file->private_data;
         struct videobuf_queue *q;
+        int res;
 
         switch (vdev->vfl_type) {
         case VFL_TYPE_GRABBER: {
@@ -314,10 +315,14 @@ static int fops_mmap(struct file *file, struct vm_area_struct * vma)
                 return 0;
         }
 
-        return videobuf_mmap_mapper(q,vma);
+        if (mutex_lock_interruptible(vdev->lock))
+                return -ERESTARTSYS;
+        res = videobuf_mmap_mapper(q, vma);
+        mutex_unlock(vdev->lock);
+        return res;
 }
 
-static unsigned int fops_poll(struct file *file, struct poll_table_struct *wait)
+static unsigned int __fops_poll(struct file *file, struct poll_table_struct *wait)
 {
         struct video_device *vdev = video_devdata(file);
         struct saa7146_fh *fh = file->private_data;
@@ -356,10 +361,22 @@ static unsigned int fops_poll(struct file *file, struct poll_table_struct *wait)
         return res;
 }
 
+static unsigned int fops_poll(struct file *file, struct poll_table_struct *wait)
+{
+        struct video_device *vdev = video_devdata(file);
+        unsigned int res;
+
+        mutex_lock(vdev->lock);
+        res = __fops_poll(file, wait);
+        mutex_unlock(vdev->lock);
+        return res;
+}
+
 static ssize_t fops_read(struct file *file, char __user *data, size_t count, loff_t *ppos)
 {
         struct video_device *vdev = video_devdata(file);
         struct saa7146_fh *fh = file->private_data;
+        int ret;
 
         switch (vdev->vfl_type) {
         case VFL_TYPE_GRABBER:
@@ -373,8 +390,13 @@ static ssize_t fops_read(struct file *file, char __user *data, size_t count, lof
                 DEB_EE("V4L2_BUF_TYPE_VBI_CAPTURE: file:%p, data:%p, count:%lu\n",
                        file, data, (unsigned long)count);
 */
-                if (fh->dev->ext_vv_data->capabilities & V4L2_CAP_VBI_CAPTURE)
-                        return saa7146_vbi_uops.read(file,data,count,ppos);
+                if (fh->dev->ext_vv_data->capabilities & V4L2_CAP_VBI_CAPTURE) {
+                        if (mutex_lock_interruptible(vdev->lock))
+                                return -ERESTARTSYS;
+                        ret = saa7146_vbi_uops.read(file, data, count, ppos);
+                        mutex_unlock(vdev->lock);
+                        return ret;
+                }
                 return -EINVAL;
         default:
                 BUG();
@@ -386,15 +408,20 @@ static ssize_t fops_write(struct file *file, const char __user *data, size_t cou
 {
         struct video_device *vdev = video_devdata(file);
         struct saa7146_fh *fh = file->private_data;
+        int ret;
 
         switch (vdev->vfl_type) {
         case VFL_TYPE_GRABBER:
                 return -EINVAL;
         case VFL_TYPE_VBI:
-                if (fh->dev->ext_vv_data->vbi_fops.write)
-                        return fh->dev->ext_vv_data->vbi_fops.write(file, data, count, ppos);
-                else
-                        return -EINVAL;
+                if (fh->dev->ext_vv_data->vbi_fops.write) {
+                        if (mutex_lock_interruptible(vdev->lock))
+                                return -ERESTARTSYS;
+                        ret = fh->dev->ext_vv_data->vbi_fops.write(file, data, count, ppos);
+                        mutex_unlock(vdev->lock);
+                        return ret;
+                }
+                return -EINVAL;
         default:
                 BUG();
                 return -EINVAL;
@@ -584,10 +611,6 @@ int saa7146_register_device(struct video_device **vid, struct saa7146_dev* dev,
         else
                 vfd->ioctl_ops = &dev->ext_vv_data->vbi_ops;
         vfd->release = video_device_release;
-        /* 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 = &dev->v4l2_lock;
         vfd->v4l2_dev = &dev->v4l2_dev;
         vfd->tvnorms = 0;