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drivers: autoconvert trivial BKL users to private mutex

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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.

These drivers do not seem to be under active
maintainance from my brief investigation. Apologies
to those maintainers that I have missed.

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: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann
2010-06-02 14:28:52 +02:00
parent 609146fdb3
commit 613655fa39
35 changed files with 216 additions and 190 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/char/lp.c
View File

@@ -126,7 +126,7 @@
#include <linux/device.h>
#include <linux/wait.h>
#include <linux/jiffies.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include <linux/compat.h>
#include <linux/parport.h>
@@ -140,6 +140,7 @@
/* if you have more than 8 printers, remember to increase LP_NO */
#define LP_NO 8
static DEFINE_MUTEX(lp_mutex);
static struct lp_struct lp_table[LP_NO];
static unsigned int lp_count = 0;
@@ -493,7 +494,7 @@ static int lp_open(struct inode * inode, struct file * file)
unsigned int minor = iminor(inode);
int ret = 0;
lock_kernel();
mutex_lock(&lp_mutex);
if (minor >= LP_NO) {
ret = -ENXIO;
goto out;
@@ -554,7 +555,7 @@ static int lp_open(struct inode * inode, struct file * file)
lp_release_parport (&lp_table[minor]);
lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;
out:
unlock_kernel();
mutex_unlock(&lp_mutex);
return ret;
}
@@ -680,7 +681,7 @@ static long lp_ioctl(struct file *file, unsigned int cmd,
int ret;
minor = iminor(file->f_path.dentry->d_inode);
lock_kernel();
mutex_lock(&lp_mutex);
switch (cmd) {
case LPSETTIMEOUT:
if (copy_from_user(&par_timeout, (void __user *)arg,
@@ -694,7 +695,7 @@ static long lp_ioctl(struct file *file, unsigned int cmd,
ret = lp_do_ioctl(minor, cmd, arg, (void __user *)arg);
break;
}
unlock_kernel();
mutex_unlock(&lp_mutex);
return ret;
}
@@ -709,7 +710,7 @@ static long lp_compat_ioctl(struct file *file, unsigned int cmd,
int ret;
minor = iminor(file->f_path.dentry->d_inode);
lock_kernel();
mutex_lock(&lp_mutex);
switch (cmd) {
case LPSETTIMEOUT:
tc = compat_ptr(arg);
@@ -730,7 +731,7 @@ static long lp_compat_ioctl(struct file *file, unsigned int cmd,
ret = lp_do_ioctl(minor, cmd, arg, compat_ptr(arg));
break;
}
unlock_kernel();
mutex_unlock(&lp_mutex);
return ret;
}