soundcore_open: Reduce the area BKL coverage
John Kacur [Sat, 3 Jul 2010 22:02:31 +0000 (00:02 +0200)]
Most of this function is protected by the sound_loader_lock.
We can push down the BKL to this call out err = file->f_op->open(inode,file);

In order to build the sound core without the BKL, we
will need to push the lock_kernel() call into the ~20
device drivers that register their file operations.

Signed-off-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/sound_core.c

index 7c2d677..c8627fc 100644 (file)
@@ -576,8 +576,6 @@ static int soundcore_open(struct inode *inode, struct file *file)
        struct sound_unit *s;
        const struct file_operations *new_fops = NULL;
 
-       lock_kernel ();
-
        chain=unit&0x0F;
        if(chain==4 || chain==5)        /* dsp/audio/dsp16 */
        {
@@ -630,18 +628,23 @@ static int soundcore_open(struct inode *inode, struct file *file)
                const struct file_operations *old_fops = file->f_op;
                file->f_op = new_fops;
                spin_unlock(&sound_loader_lock);
-               if(file->f_op->open)
+
+               if (file->f_op->open) {
+                       /* TODO: push down BKL into indivial open functions */
+                       lock_kernel();
                        err = file->f_op->open(inode,file);
+                       unlock_kernel();
+               }
+
                if (err) {
                        fops_put(file->f_op);
                        file->f_op = fops_get(old_fops);
                }
+
                fops_put(old_fops);
-               unlock_kernel();
                return err;
        }
        spin_unlock(&sound_loader_lock);
-       unlock_kernel();
        return -ENODEV;
 }