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Commit 5aa82940 authored by Arnd Bergmann's avatar Arnd Bergmann
Browse files

mtd: autoconvert trivial BKL users to private mutex 



All these files use the big kernel lock in a trivial
way to serialize their private file operations,
typically resulting from an earlier semi-automatic
pushdown from VFS.

None of these drivers appears to want to lock against
other code, and they all use the BKL as the top-level
lock in their file operations, meaning that there
is no lock-order inversion problem.

Consequently, we can remove the BKL completely,
replacing it with a per-file mutex in every case.
Using a scripted approach means we can avoid
typos.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
    if grep -q 'include.*linux.mutex.h' ${file} ; then
            sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
    else
            sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
    fi
    sed -i ${file} \
        -e "/^#include.*linux.mutex.h/,$ {
                1,/^\(static\|int\|long\)/ {
                     /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }"  \
    -e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
    -e '/[      ]*cycle_kernel_lock();/d'
else
    sed -i -e '/include.*\<smp_lock.h\>/d' ${file}  \
                -e '/cycle_kernel_lock()/d'
fi

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Cc: linux-mtd@lists.infradead.org
parent c45d15d2

drivers/mtd/mtdchar.c

+8 −7
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ 
#include <linux/module.h>

#include <linux/slab.h>

#include <linux/sched.h>

#include <linux/smp_lock.h>

#include <linux/mutex.h>

#include <linux/backing-dev.h>

#include <linux/compat.h>

#include <linux/mount.h>
@@ -37,6 +37,7 @@ 
#include <asm/uaccess.h>



#define MTD_INODE_FS_MAGIC 0x11307854

static DEFINE_MUTEX(mtd_mutex);

static struct vfsmount *mtd_inode_mnt __read_mostly;



/*
@@ -90,7 +91,7 @@ static int mtd_open(struct inode *inode, struct file *file) 
	if ((file->f_mode & FMODE_WRITE) && (minor & 1))

		return -EACCES;



	lock_kernel();

	mutex_lock(&mtd_mutex);

	mtd = get_mtd_device(NULL, devnum);



	if (IS_ERR(mtd)) {
@@ -138,7 +139,7 @@ static int mtd_open(struct inode *inode, struct file *file) 
	file->private_data = mfi;



out:

	unlock_kernel();

	mutex_unlock(&mtd_mutex);

	return ret;

} /* mtd_open */
@@ -866,9 +867,9 @@ static long mtd_unlocked_ioctl(struct file *file, u_int cmd, u_long arg) 
{

	int ret;



	lock_kernel();

	mutex_lock(&mtd_mutex);

	ret = mtd_ioctl(file, cmd, arg);

	unlock_kernel();

	mutex_unlock(&mtd_mutex);



	return ret;

}
@@ -892,7 +893,7 @@ static long mtd_compat_ioctl(struct file *file, unsigned int cmd, 
	void __user *argp = compat_ptr(arg);

	int ret = 0;



	lock_kernel();

	mutex_lock(&mtd_mutex);



	switch (cmd) {

	case MEMWRITEOOB32:
@@ -927,7 +928,7 @@ static long mtd_compat_ioctl(struct file *file, unsigned int cmd, 
		ret = mtd_ioctl(file, cmd, (unsigned long)argp);

	}



	unlock_kernel();

	mutex_unlock(&mtd_mutex);



	return ret;

}