lkml.org 
[lkml]   [2010]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4/7] ipmi: autoconvert trivial BKL users to private mutex
Date
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: Corey Minyard <minyard@acm.org>
Cc: openipmi-developer@lists.sourceforge.net
---
drivers/char/ipmi/ipmi_devintf.c | 14 +++++++-------
drivers/char/ipmi/ipmi_watchdog.c | 8 ++++----
2 files changed, 11 insertions(+), 11 deletions(-)
diff --git a/drivers/char/ipmi/ipmi_devintf.c b/drivers/char/ipmi/ipmi_devintf.c
index d8ec92a..44833de 100644
--- a/drivers/char/ipmi/ipmi_devintf.c
+++ b/drivers/char/ipmi/ipmi_devintf.c
@@ -44,7 +44,6 @@
#include <linux/init.h>
#include <linux/device.h>
#include <linux/compat.h>
-#include <linux/smp_lock.h>

struct ipmi_file_private
{
@@ -59,6 +58,7 @@ struct ipmi_file_private
unsigned int default_retry_time_ms;
};

+static DEFINE_MUTEX(ipmi_mutex);
static void file_receive_handler(struct ipmi_recv_msg *msg,
void *handler_data)
{
@@ -102,9 +102,9 @@ static int ipmi_fasync(int fd, struct file *file, int on)
struct ipmi_file_private *priv = file->private_data;
int result;

- lock_kernel(); /* could race against open() otherwise */
+ mutex_lock(&ipmi_mutex); /* could race against open() otherwise */
result = fasync_helper(fd, file, on, &priv->fasync_queue);
- unlock_kernel();
+ mutex_unlock(&ipmi_mutex);

return (result);
}
@@ -125,7 +125,7 @@ static int ipmi_open(struct inode *inode, struct file *file)
if (!priv)
return -ENOMEM;

- lock_kernel();
+ mutex_lock(&ipmi_mutex);
priv->file = file;

rv = ipmi_create_user(if_num,
@@ -150,7 +150,7 @@ static int ipmi_open(struct inode *inode, struct file *file)
priv->default_retry_time_ms = 0;

out:
- unlock_kernel();
+ mutex_unlock(&ipmi_mutex);
return rv;
}

@@ -639,9 +639,9 @@ static long ipmi_unlocked_ioctl(struct file *file,
{
int ret;

- lock_kernel();
+ mutex_lock(&ipmi_mutex);
ret = ipmi_ioctl(file, cmd, data);
- unlock_kernel();
+ mutex_unlock(&ipmi_mutex);

return ret;
}
diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index 654d566..ed10b74 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -35,7 +35,7 @@
#include <linux/moduleparam.h>
#include <linux/ipmi.h>
#include <linux/ipmi_smi.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/watchdog.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
@@ -149,6 +149,7 @@
#define WDIOC_GET_PRETIMEOUT _IOW(WATCHDOG_IOCTL_BASE, 22, int)
#endif

+static DEFINE_MUTEX(ipmi_watchdog_mutex);
static int nowayout = WATCHDOG_NOWAYOUT;

static ipmi_user_t watchdog_user;
@@ -748,9 +749,9 @@ static long ipmi_unlocked_ioctl(struct file *file,
{
int ret;

- lock_kernel();
+ mutex_lock(&ipmi_watchdog_mutex);
ret = ipmi_ioctl(file, cmd, arg);
- unlock_kernel();
+ mutex_unlock(&ipmi_watchdog_mutex);

return ret;
}
@@ -844,7 +845,6 @@ static int ipmi_open(struct inode *ino, struct file *filep)
if (test_and_set_bit(0, &ipmi_wdog_open))
return -EBUSY;

- cycle_kernel_lock();

/*
* Don't start the timer now, let it start on the
--
1.7.1


\
 
 \ /
  Last update: 2010-09-14 21:57    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site