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usbcore: cdev lock_kernel() pushdown

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usb_open() is protected by a down_read(&minor_rwsem), but I'm not sure I
trust it to protect everything including subsidiary open() functions.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Jonathan Corbet 2008-05-15 16:24:25 -06:00
parent 1bcaa0bd6f
commit 20613f24bc
1 changed files with 3 additions and 0 deletions
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3
drivers/usb/core/file.c
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@ -18,6 +18,7 @@
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/rwsem.h>
#include <linux/smp_lock.h>
#include <linux/usb.h>
#include "usb.h"
@ -33,6 +34,7 @@ static int usb_open(struct inode * inode, struct file * file)
int err = -ENODEV;
const struct file_operations *old_fops, *new_fops = NULL;
lock_kernel();
down_read(&minor_rwsem);
c = usb_minors[minor];
@ -51,6 +53,7 @@ static int usb_open(struct inode * inode, struct file * file)
fops_put(old_fops);
done:
up_read(&minor_rwsem);
unlock_kernel();
return err;
}