block: autoconvert trivial BKL users to private mutex

The block device drivers have all gained new lock_kernel
calls from a recent pushdown, and some of the drivers
were already using the BKL before.

This turns the BKL into a set of per-driver mutexes.
Still need to check whether this is safe to do.

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>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 0daa422aa28..a32fb41246f 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -24,7 +24,7 @@
 #include <linux/errno.h>
 #include <linux/file.h>
 #include <linux/ioctl.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/compiler.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
@@ -53,6 +53,7 @@
 #define DBG_BLKDEV      0x0100
 #define DBG_RX          0x0200
 #define DBG_TX          0x0400
+static DEFINE_MUTEX(nbd_mutex);
 static unsigned int debugflags;
 #endif /* NDEBUG */
 
@@ -717,11 +718,11 @@ static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
 	dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
 			lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
 
-	lock_kernel();
+	mutex_lock(&nbd_mutex);
 	mutex_lock(&lo->tx_lock);
 	error = __nbd_ioctl(bdev, lo, cmd, arg);
 	mutex_unlock(&lo->tx_lock);
-	unlock_kernel();
+	mutex_unlock(&nbd_mutex);
 
 	return error;
 }