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, 6 insertions, 5 deletions

diff --git a/drivers/scsi/mpt2sas/mpt2sas_ctl.c b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
index b774973..31cf126 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_ctl.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
@@ -51,7 +51,7 @@
 #include <linux/types.h>
 #include <linux/pci.h>
 #include <linux/delay.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/compat.h>
 #include <linux/poll.h>
 
@@ -61,6 +61,7 @@
 #include "mpt2sas_base.h"
 #include "mpt2sas_ctl.h"
 
+static DEFINE_MUTEX(_ctl_mutex);
 static struct fasync_struct *async_queue;
 static DECLARE_WAIT_QUEUE_HEAD(ctl_poll_wait);
 
@@ -2238,9 +2239,9 @@ _ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	long ret;
 
-	lock_kernel();
+	mutex_lock(&_ctl_mutex);
 	ret = _ctl_ioctl_main(file, cmd, (void __user *)arg);
-	unlock_kernel();
+	mutex_unlock(&_ctl_mutex);
 	return ret;
 }
 
@@ -2309,12 +2310,12 @@ _ctl_ioctl_compat(struct file *file, unsigned cmd, unsigned long arg)
 {
 	long ret;
 
-	lock_kernel();
+	mutex_lock(&_ctl_mutex);
 	if (cmd == MPT2COMMAND32)
 		ret = _ctl_compat_mpt_command(file, cmd, arg);
 	else
 		ret = _ctl_ioctl_main(file, cmd, (void __user *)arg);
-	unlock_kernel();
+	mutex_unlock(&_ctl_mutex);
 	return ret;
 }
 #endif