scsi: 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: linux-scsi@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@suse.de>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/scsi/megaraid.c b/drivers/scsi/megaraid.c
index 0b6e322..4d0cf5c 100644
--- a/drivers/scsi/megaraid.c
+++ b/drivers/scsi/megaraid.c
@@ -46,7 +46,7 @@
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/dma-mapping.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/slab.h>
 #include <scsi/scsicam.h>
 
@@ -62,6 +62,7 @@ MODULE_DESCRIPTION ("LSI Logic MegaRAID legacy driver");
 MODULE_LICENSE ("GPL");
 MODULE_VERSION(MEGARAID_MODULE_VERSION);
 
+static DEFINE_MUTEX(megadev_mutex);
 static unsigned int max_cmd_per_lun = DEF_CMD_PER_LUN;
 module_param(max_cmd_per_lun, uint, 0);
 MODULE_PARM_DESC(max_cmd_per_lun, "Maximum number of commands which can be issued to a single LUN (default=DEF_CMD_PER_LUN=63)");
@@ -3282,7 +3283,6 @@ mega_init_scb(adapter_t *adapter)
 static int
 megadev_open (struct inode *inode, struct file *filep)
 {
-	cycle_kernel_lock();
 	/*
 	 * Only allow superuser to access private ioctl interface
 	 */
@@ -3701,9 +3701,9 @@ megadev_unlocked_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
 {
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&megadev_mutex);
 	ret = megadev_ioctl(filep, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&megadev_mutex);
 
 	return ret;
 }