UIO: BKL removal

Fill in needed locking around idr accesses, then remove the big kernel lock
from the UIO driver.  Since there are no in-tree UIO drivers with open()
methods, no further BKL pushdown is required.

Acked-by: Hans J. Koch <hjk@linutronix.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 3a6934bf713134edc3f53b68e25bf913ec3215e4..4f28f4bf836603e5a78ec1ea8435cc0f63e8dc2c 100644 (file)
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -47,6 +47,9 @@ static struct uio_class {
        struct class *class;
 } *uio_class;
 
+/* Protect idr accesses */
+static DEFINE_MUTEX(minor_lock);
+
 /*
  * attributes
  */
@@ -231,7 +234,6 @@ static void uio_dev_del_attributes(struct uio_device *idev)
 
 static int uio_get_minor(struct uio_device *idev)
 {
-       static DEFINE_MUTEX(minor_lock);
        int retval = -ENOMEM;
        int id;
 
@@ -253,7 +255,9 @@ exit:
 
 static void uio_free_minor(struct uio_device *idev)
 {
+       mutex_lock(&minor_lock);
        idr_remove(&uio_idr, idev->minor);
+       mutex_unlock(&minor_lock);
 }
 
 /**
@@ -297,8 +301,9 @@ static int uio_open(struct inode *inode, struct file *filep)
        struct uio_listener *listener;
        int ret = 0;
 
-       lock_kernel();
+       mutex_lock(&minor_lock);
        idev = idr_find(&uio_idr, iminor(inode));
+       mutex_unlock(&minor_lock);
        if (!idev) {
                ret = -ENODEV;
                goto out;
@@ -324,18 +329,15 @@ static int uio_open(struct inode *inode, struct file *filep)
                if (ret)
                        goto err_infoopen;
        }
-       unlock_kernel();
        return 0;
 
 err_infoopen:
-
        kfree(listener);
-err_alloc_listener:
 
+err_alloc_listener:
        module_put(idev->owner);
 
 out:
-       unlock_kernel();
        return ret;
 }