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Commit 20613f24 authored by Jonathan Corbet's avatar Jonathan Corbet
Browse files

usbcore: cdev lock_kernel() pushdown 



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: default avatarJonathan Corbet <corbet@lwn.net>
parent 1bcaa0bd

drivers/usb/core/file.c

+3 −0
Original line number Diff line number Diff line
@@ -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;

}