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>

diff --git a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c
index a96f319..43412c0 100644 (file)
--- 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;
 }