agp: Remove the BKL from agp_open

- Remove the BKL from agp_open
- Perform a few clean-ups.

Analysis:
---------
int minor is local to the function.

The following are protected by agp_fe.agp_mutex
struct agp_file_private *priv;
struct agp_client *client;

Call-outs:

kzalloc should be safe to call under the mutex_lock

agp_find_client_by_pid:
	- agp_mmap calls that under agp_fe.agp_mutex which we hold in agp_open
	- agpioc_reserve_wrap calls it without any locking what-so-ever.
		- Is that an error? Or is that okay because it has pid that is
		  a unique handle?

agp_insert_file_private:
	- This function only manipulates struct agp_file_private, once again
	  while agp_fe.agp_mutex is held

Signed-off-by: John Kacur <jkacur@redhat.com>
Acked-by: David Airlie <airlied@linux.ie>
LKML-Reference: <alpine.LFD.2.00.0910112216060.12574@localhost.localdomain>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 11 insertions, 17 deletions

diff --git a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c
index a96f3197e60f..43412c03969e 100644
--- a/drivers/char/agp/frontend.c
+++ b/drivers/char/agp/frontend.c
@@ -676,25 +676,25 @@ static int agp_open(struct inode *inode, struct file *file)
         int minor = iminor(inode);
         struct agp_file_private *priv;
         struct agp_client *client;
-        int rc = -ENXIO;
-
-        lock_kernel();
-        mutex_lock(&(agp_fe.agp_mutex));
 
         if (minor != AGPGART_MINOR)
-                goto err_out;
+                return -ENXIO;
+
+        mutex_lock(&(agp_fe.agp_mutex));
 
         priv = kzalloc(sizeof(struct agp_file_private), GFP_KERNEL);
-        if (priv == NULL)
-                goto err_out_nomem;
+        if (priv == NULL) {
+                mutex_unlock(&(agp_fe.agp_mutex));
+                return -ENOMEM;
+        }
 
         set_bit(AGP_FF_ALLOW_CLIENT, &priv->access_flags);
         priv->my_pid = current->pid;
 
-        if (capable(CAP_SYS_RAWIO)) {
+        if (capable(CAP_SYS_RAWIO))
                 /* Root priv, can be controller */
                 set_bit(AGP_FF_ALLOW_CONTROLLER, &priv->access_flags);
-        }
+
         client = agp_find_client_by_pid(current->pid);
 
         if (client != NULL) {
@@ -704,16 +704,10 @@ static int agp_open(struct inode *inode, struct file *file)
         file->private_data = (void *) priv;
         agp_insert_file_private(priv);
         DBG("private=%p, client=%p", priv, client);
-        mutex_unlock(&(agp_fe.agp_mutex));
-        unlock_kernel();
-        return 0;
 
-err_out_nomem:
-        rc = -ENOMEM;
-err_out:
         mutex_unlock(&(agp_fe.agp_mutex));
-        unlock_kernel();
-        return rc;
+
+        return 0;
 }