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mac: 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.

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>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@ozlabs.org
This commit is contained in:
Arnd Bergmann
2010-06-02 14:28:52 +02:00
parent 5aa82940b2
commit d851b6e04e
3 changed files with 14 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/macintosh/adb.c
View File

@ -24,7 +24,6 @@
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/adb.h>
#include <linux/cuda.h>
#include <linux/pmu.h>
@ -55,6 +54,7 @@ extern struct adb_driver adb_iop_driver;
extern struct adb_driver via_pmu_driver;
extern struct adb_driver macio_adb_driver;
static DEFINE_MUTEX(adb_mutex);
static struct adb_driver *adb_driver_list[] = {
#ifdef CONFIG_ADB_MACII
&via_macii_driver,
@ -647,7 +647,7 @@ static int adb_open(struct inode *inode, struct file *file)
struct adbdev_state *state;
int ret = 0;
lock_kernel();
mutex_lock(&adb_mutex);
if (iminor(inode) > 0 || adb_controller == NULL) {
ret = -ENXIO;
goto out;
@ -665,7 +665,7 @@ static int adb_open(struct inode *inode, struct file *file)
state->inuse = 1;
out:
unlock_kernel();
mutex_unlock(&adb_mutex);
return ret;
}
@ -674,7 +674,7 @@ static int adb_release(struct inode *inode, struct file *file)
struct adbdev_state *state = file->private_data;
unsigned long flags;
lock_kernel();
mutex_lock(&adb_mutex);
if (state) {
file->private_data = NULL;
spin_lock_irqsave(&state->lock, flags);
@ -687,7 +687,7 @@ static int adb_release(struct inode *inode, struct file *file)
spin_unlock_irqrestore(&state->lock, flags);
}
}
unlock_kernel();
mutex_unlock(&adb_mutex);
return 0;
}