2008-11-27 10:33:05

by Martin Schwidefsky

[permalink] [raw]
Subject: [patch 01/60] vmcp: remove BKL

From: Christian Borntraeger <[email protected]>

The vmcp driver uses the session->mutex for concurrent access of the data
structures. Therefore, the BKL in vmcp_open does not protect against any
other function in the driver.
The BLK in vmcp_open would protect concurrent access to the module init
but all necessary steps ave finished before misc_register is called.
We can safely remove the lock_kernel from vcmp.

Signed-off-by: Christian Borntraeger <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---

drivers/s390/char/vmcp.c | 3 ---
1 file changed, 3 deletions(-)

Index: quilt-2.6/drivers/s390/char/vmcp.c
===================================================================
--- quilt-2.6.orig/drivers/s390/char/vmcp.c
+++ quilt-2.6/drivers/s390/char/vmcp.c
@@ -16,7 +16,6 @@
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
-#include <linux/smp_lock.h>
#include <asm/cpcmd.h>
#include <asm/debug.h>
#include <asm/uaccess.h>
@@ -41,13 +40,11 @@ static int vmcp_open(struct inode *inode
if (!session)
return -ENOMEM;

- lock_kernel();
session->bufsize = PAGE_SIZE;
session->response = NULL;
session->resp_size = 0;
mutex_init(&session->mutex);
file->private_data = session;
- unlock_kernel();
return nonseekable_open(inode, file);
}


--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.