[PATCH 3/7] mac: autoconvert trivial BKL users to private mutex

From: Arnd Bergmann
Date: Tue Sep 14 2010 - 15:53:59 EST


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@xxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: linuxppc-dev@xxxxxxxxxx
---
drivers/macintosh/adb.c | 10 +++++-----
drivers/macintosh/smu.c | 6 +++---
drivers/macintosh/via-pmu.c | 11 ++++++-----
3 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/drivers/macintosh/adb.c b/drivers/macintosh/adb.c
index 1c4ee6e..e75e3be 100644
--- a/drivers/macintosh/adb.c
+++ b/drivers/macintosh/adb.c
@@ -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;
}

diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c
index e58c3d3..290cb32 100644
--- a/drivers/macintosh/smu.c
+++ b/drivers/macintosh/smu.c
@@ -19,7 +19,6 @@
* the userland interface
*/

-#include <linux/smp_lock.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/device.h>
@@ -97,6 +96,7 @@ struct smu_device {
* I don't think there will ever be more than one SMU, so
* for now, just hard code that
*/
+static DEFINE_MUTEX(smu_mutex);
static struct smu_device *smu;
static DEFINE_MUTEX(smu_part_access);
static int smu_irq_inited;
@@ -1095,12 +1095,12 @@ static int smu_open(struct inode *inode, struct file *file)
pp->mode = smu_file_commands;
init_waitqueue_head(&pp->wait);

- lock_kernel();
+ mutex_lock(&smu_mutex);
spin_lock_irqsave(&smu_clist_lock, flags);
list_add(&pp->list, &smu_clist);
spin_unlock_irqrestore(&smu_clist_lock, flags);
file->private_data = pp;
- unlock_kernel();
+ mutex_unlock(&smu_mutex);

return 0;
}
diff --git a/drivers/macintosh/via-pmu.c b/drivers/macintosh/via-pmu.c
index 2d17e76..7b8b1de 100644
--- a/drivers/macintosh/via-pmu.c
+++ b/drivers/macintosh/via-pmu.c
@@ -18,7 +18,7 @@
*
*/
#include <stdarg.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
@@ -73,6 +73,7 @@
/* How many iterations between battery polls */
#define BATTERY_POLLING_COUNT 2

+static DEFINE_MUTEX(pmu_info_proc_mutex);
static volatile unsigned char __iomem *via;

/* VIA registers - spaced 0x200 bytes apart */
@@ -2078,7 +2079,7 @@ pmu_open(struct inode *inode, struct file *file)
pp->rb_get = pp->rb_put = 0;
spin_lock_init(&pp->lock);
init_waitqueue_head(&pp->wait);
- lock_kernel();
+ mutex_lock(&pmu_info_proc_mutex);
spin_lock_irqsave(&all_pvt_lock, flags);
#if defined(CONFIG_INPUT_ADBHID) && defined(CONFIG_PMAC_BACKLIGHT)
pp->backlight_locker = 0;
@@ -2086,7 +2087,7 @@ pmu_open(struct inode *inode, struct file *file)
list_add(&pp->list, &all_pmu_pvt);
spin_unlock_irqrestore(&all_pvt_lock, flags);
file->private_data = pp;
- unlock_kernel();
+ mutex_unlock(&pmu_info_proc_mutex);
return 0;
}

@@ -2343,9 +2344,9 @@ static long pmu_unlocked_ioctl(struct file *filp,
{
int ret;

- lock_kernel();
+ mutex_lock(&pmu_info_proc_mutex);
ret = pmu_ioctl(filp, cmd, arg);
- unlock_kernel();
+ mutex_unlock(&pmu_info_proc_mutex);

return ret;
}
--
1.7.1

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