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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>
This commit is contained in:
John Kacur 2009-10-11 22:24:25 +02:00 committed by Thomas Gleixner
parent f96d3015e9
commit 55e858c848
1 changed files with 11 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/char/agp/frontend.c
View File

@ -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;
}