net: autoconvert trivial BKL users to private mutex
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: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index e7b4187..6695a51 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>
@@ -180,6 +179,7 @@
* channel.downl.
*/
+static DEFINE_MUTEX(ppp_mutex);
static atomic_t ppp_unit_count = ATOMIC_INIT(0);
static atomic_t channel_count = ATOMIC_INIT(0);
@@ -362,7 +362,6 @@
*/
static int ppp_open(struct inode *inode, struct file *file)
{
- cycle_kernel_lock();
/*
* This could (should?) be enforced by the permissions on /dev/ppp.
*/
@@ -582,7 +581,7 @@
* 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)
@@ -594,7 +593,7 @@
} else
printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
atomic_long_read(&file->f_count));
- unlock_kernel();
+ mutex_unlock(&ppp_mutex);
return err;
}
@@ -602,7 +601,7 @@
struct channel *pch;
struct ppp_channel *chan;
- lock_kernel();
+ mutex_lock(&ppp_mutex);
pch = PF_TO_CHANNEL(pf);
switch (cmd) {
@@ -624,7 +623,7 @@
err = chan->ops->ioctl(chan, cmd, arg);
up_read(&pch->chan_sem);
}
- unlock_kernel();
+ mutex_unlock(&ppp_mutex);
return err;
}
@@ -634,7 +633,7 @@
return -EINVAL;
}
- lock_kernel();
+ mutex_lock(&ppp_mutex);
ppp = PF_TO_PPP(pf);
switch (cmd) {
case PPPIOCSMRU:
@@ -782,7 +781,7 @@
default:
err = -ENOTTY;
}
- unlock_kernel();
+ mutex_unlock(&ppp_mutex);
return err;
}
@@ -795,7 +794,7 @@
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 */
@@ -846,7 +845,7 @@
default:
err = -ENOTTY;
}
- unlock_kernel();
+ mutex_unlock(&ppp_mutex);
return err;
}