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isdn: 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: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arnd Bergmann
2010-07-11 11:18:53 +00:00
committed by David S. Miller
parent d361fd599a
commit 76a64921da
9 changed files with 48 additions and 46 deletions
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15
drivers/isdn/hysdn/hysdn_proclog.c
View File

@@ -15,13 +15,14 @@
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include "hysdn_defs.h"
/* the proc subdir for the interface is defined in the procconf module */
extern struct proc_dir_entry *hysdn_proc_entry;
static DEFINE_MUTEX(hysdn_log_mutex);
static void put_log_buffer(hysdn_card * card, char *cp);
/*************************************************/
@@ -251,7 +252,7 @@ hysdn_log_open(struct inode *ino, struct file *filep)
struct procdata *pd = NULL;
unsigned long flags;
lock_kernel();
mutex_lock(&hysdn_log_mutex);
card = card_root;
while (card) {
pd = card->proclog;
@@ -260,7 +261,7 @@ hysdn_log_open(struct inode *ino, struct file *filep)
card = card->next; /* search next entry */
}
if (!card) {
unlock_kernel();
mutex_unlock(&hysdn_log_mutex);
return (-ENODEV); /* device is unknown/invalid */
}
filep->private_data = card; /* remember our own card */
@@ -278,10 +279,10 @@ hysdn_log_open(struct inode *ino, struct file *filep)
filep->private_data = &pd->log_head;
spin_unlock_irqrestore(&card->hysdn_lock, flags);
} else { /* simultaneous read/write access forbidden ! */
unlock_kernel();
mutex_unlock(&hysdn_log_mutex);
return (-EPERM); /* no permission this time */
}
unlock_kernel();
mutex_unlock(&hysdn_log_mutex);
return nonseekable_open(ino, filep);
} /* hysdn_log_open */
@@ -300,7 +301,7 @@ hysdn_log_close(struct inode *ino, struct file *filep)
hysdn_card *card;
int retval = 0;
lock_kernel();
mutex_lock(&hysdn_log_mutex);
if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
/* write only access -> write debug level written */
retval = 0; /* success */
@@ -339,7 +340,7 @@ hysdn_log_close(struct inode *ino, struct file *filep)
kfree(inf);
}
} /* read access */
unlock_kernel();
mutex_unlock(&hysdn_log_mutex);
return (retval);
} /* hysdn_log_close */