Input: remove BKL, fix input_open_file() locking

Holding the BKL in input_open_file seems pointless because it does not
protect against updates of input_table, and all open functions from the
underlying drivers have proper mutex locking.

This makes input_open_file take the input_mutex when accessing
the table and no lock when calling into the lower function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 10 insertions, 8 deletions

diff --git a/drivers/input/input.c b/drivers/input/input.c
index e2dd8858e19d..e2aad0a51826 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -1879,35 +1879,37 @@ static int input_open_file(struct inode *inode, struct file *file)
         const struct file_operations *old_fops, *new_fops = NULL;
         int err;
 
-        lock_kernel();
+        err = mutex_lock_interruptible(&input_mutex);
+        if (err)
+                return err;
+
         /* No load-on-demand here? */
         handler = input_table[iminor(inode) >> 5];
-        if (!handler || !(new_fops = fops_get(handler->fops))) {
-                err = -ENODEV;
-                goto out;
-        }
+        if (handler)
+                new_fops = fops_get(handler->fops);
+
+        mutex_unlock(&input_mutex);
 
         /*
          * That's _really_ odd. Usually NULL ->open means "nothing special",
          * not "no device". Oh, well...
          */
-        if (!new_fops->open) {
+        if (!new_fops || !new_fops->open) {
                 fops_put(new_fops);
                 err = -ENODEV;
                 goto out;
         }
+
         old_fops = file->f_op;
         file->f_op = new_fops;
 
         err = new_fops->open(inode, file);
-
         if (err) {
                 fops_put(file->f_op);
                 file->f_op = fops_get(old_fops);
         }
         fops_put(old_fops);
 out:
-        unlock_kernel();
         return err;
 }