Prev: [PATCH 07/12] cris: autoconvert trivial BKL users to private mutex
Next: [PATCH 03/12] scsi: autoconvert trivial BKL users to private mutex
From: Arnd Bergmann on 11 Jul 2010 17:30
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(a)arndb.de>
Cc: "David S. Miller" <davem(a)davemloft.net>
Cc: netdev(a)vger.kernel.org
---
drivers/net/ppp_generic.c | 19 +++++++++----------
drivers/net/wan/cosa.c | 10 +++++-----
net/wanrouter/wanmain.c | 7 ++++---
net/wanrouter/wanproc.c | 7 ++++---
4 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 1b2c291..a72a335 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -40,7 +40,6 @@
#include <linux/if_arp.h>
#include <linux/ip.h>
#include <linux/tcp.h>
-#include <linux/smp_lock.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/stddef.h>
@@ -181,6 +180,7 @@ struct channel {
* channel.downl.
*/

+static DEFINE_MUTEX(ppp_mutex);
static atomic_t ppp_unit_count = ATOMIC_INIT(0);
static atomic_t channel_count = ATOMIC_INIT(0);

@@ -363,7 +363,6 @@ static const int npindex_to_ethertype[NUM_NP] = {
*/
static int ppp_open(struct inode *inode, struct file *file)
{
- cycle_kernel_lock();
/*
* This could (should?) be enforced by the permissions on /dev/ppp.
*/
@@ -588,7 +587,7 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
* this fd and reopening /dev/ppp.
*/
err = -EINVAL;
- lock_kernel();
+ mutex_lock(&ppp_mutex);
if (pf->kind == INTERFACE) {
ppp = PF_TO_PPP(pf);
if (file == ppp->owner)
@@ -600,7 +599,7 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
} else
printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
atomic_long_read(&file->f_count));
- unlock_kernel();
+ mutex_unlock(&ppp_mutex);
return err;
}

@@ -608,7 +607,7 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
struct channel *pch;
struct ppp_channel *chan;

- lock_kernel();
+ mutex_lock(&ppp_mutex);
pch = PF_TO_CHANNEL(pf);

switch (cmd) {
@@ -630,7 +629,7 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
err = chan->ops->ioctl(chan, cmd, arg);
up_read(&pch->chan_sem);
}
- unlock_kernel();
+ mutex_unlock(&ppp_mutex);
return err;
}

@@ -640,7 +639,7 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
return -EINVAL;
}

- lock_kernel();
+ mutex_lock(&ppp_mutex);
ppp = PF_TO_PPP(pf);
switch (cmd) {
case PPPIOCSMRU:
@@ -788,7 +787,7 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
default:
err = -ENOTTY;
}
- unlock_kernel();
+ mutex_unlock(&ppp_mutex);
return err;
}

@@ -801,7 +800,7 @@ static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
struct ppp_net *pn;
int __user *p = (int __user *)arg;

- lock_kernel();
+ mutex_lock(&ppp_mutex);
switch (cmd) {
case PPPIOCNEWUNIT:
/* Create a new ppp unit */
@@ -852,7 +851,7 @@ static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
default:
err = -ENOTTY;
}
- unlock_kernel();
+ mutex_unlock(&ppp_mutex);
return err;
}

diff --git a/drivers/net/wan/cosa.c b/drivers/net/wan/cosa.c
index f0bd70f..04c6cd4 100644
--- a/drivers/net/wan/cosa.c
+++ b/drivers/net/wan/cosa.c
@@ -89,7 +89,6 @@
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/device.h>
-#include <linux/smp_lock.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/byteorder.h>
@@ -174,6 +173,7 @@ struct cosa_data {
* Character device major number. 117 was allocated for us.
* The value of 0 means to allocate a first free one.
*/
+static DEFINE_MUTEX(cosa_chardev_mutex);
static int cosa_major = 117;

/*
@@ -944,7 +944,7 @@ static int cosa_open(struct inode *inode, struct file *file)
int n;
int ret = 0;

- lock_kernel();
+ mutex_lock(&cosa_chardev_mutex);
if ((n=iminor(file->f_path.dentry->d_inode)>>CARD_MINOR_BITS)
>= nr_cards) {
ret = -ENODEV;
@@ -976,7 +976,7 @@ static int cosa_open(struct inode *inode, struct file *file)
chan->rx_done = chrdev_rx_done;
spin_unlock_irqrestore(&cosa->lock, flags);
out:
- unlock_kernel();
+ mutex_unlock(&cosa_chardev_mutex);
return ret;
}

@@ -1212,10 +1212,10 @@ static long cosa_chardev_ioctl(struct file *file, unsigned int cmd,
struct cosa_data *cosa;
long ret;

- lock_kernel();
+ mutex_lock(&cosa_chardev_mutex);
cosa = channel->cosa;
ret = cosa_ioctl_common(cosa, channel, cmd, arg);
- unlock_kernel();
+ mutex_unlock(&cosa_chardev_mutex);
return ret;
}

diff --git a/net/wanrouter/wanmain.c b/net/wanrouter/wanmain.c
index 258daa8..2bf2340 100644
--- a/net/wanrouter/wanmain.c
+++ b/net/wanrouter/wanmain.c
@@ -48,7 +48,7 @@
#include <linux/kernel.h>
#include <linux/module.h> /* support for loadable modules */
#include <linux/slab.h> /* kmalloc(), kfree() */
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/mm.h>
#include <linux/string.h> /* inline mem*, str* functions */

@@ -71,6 +71,7 @@
* WAN device IOCTL handlers
*/

+static DEFINE_MUTEX(wanrouter_mutex);
static int wanrouter_device_setup(struct wan_device *wandev,
wandev_conf_t __user *u_conf);
static int wanrouter_device_stat(struct wan_device *wandev,
@@ -376,7 +377,7 @@ long wanrouter_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (wandev->magic != ROUTER_MAGIC)
return -EINVAL;

- lock_kernel();
+ mutex_lock(&wanrouter_mutex);
switch (cmd) {
case ROUTER_SETUP:
err = wanrouter_device_setup(wandev, data);
@@ -408,7 +409,7 @@ long wanrouter_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
err = wandev->ioctl(wandev, cmd, arg);
else err = -EINVAL;
}
- unlock_kernel();
+ mutex_unlock(&wanrouter_mutex);
return err;
}

diff --git a/net/wanrouter/wanproc.c b/net/wanrouter/wanproc.c
index c44d96b..11f25c7 100644
--- a/net/wanrouter/wanproc.c
+++ b/net/wanrouter/wanproc.c
@@ -27,7 +27,7 @@
#include <linux/module.h>
#include <linux/wanrouter.h> /* WAN router API definitions */
#include <linux/seq_file.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>

#include <net/net_namespace.h>
#include <asm/io.h>
@@ -66,6 +66,7 @@
* /proc/net/router
*/

+static DEFINE_MUTEX(config_mutex);
static struct proc_dir_entry *proc_router;

/* Strings */
@@ -85,7 +86,7 @@ static void *r_start(struct seq_file *m, loff_t *pos)
struct wan_device *wandev;
loff_t l = *pos;

- lock_kernel();
+ mutex_lock(&config_mutex);
if (!l--)
return SEQ_START_TOKEN;
for (wandev = wanrouter_router_devlist; l-- && wandev;
@@ -104,7 +105,7 @@ static void *r_next(struct seq_file *m, void *v, loff_t *pos)
static void r_stop(struct seq_file *m, void *v)
__releases(kernel_lock)
{
- unlock_kernel();
+ mutex_unlock(&config_mutex);
}

static int config_show(struct seq_file *m, void *v)
--
1.7.1

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Next: [PATCH 03/12] scsi: autoconvert trivial BKL users to private mutex