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, 3 insertions, 4 deletions

diff --git a/drivers/scsi/3w-sas.c b/drivers/scsi/3w-sas.c
index f481e734aad..7e5f2385e3e 100644
--- a/drivers/scsi/3w-sas.c
+++ b/drivers/scsi/3w-sas.c
@@ -64,7 +64,6 @@
 #include <linux/pci.h>
 #include <linux/time.h>
 #include <linux/mutex.h>
-#include <linux/smp_lock.h>
 #include <linux/slab.h>
 #include <asm/io.h>
 #include <asm/irq.h>
@@ -77,6 +76,7 @@
 
 /* Globals */
 #define TW_DRIVER_VERSION "3.26.02.000"
+static DEFINE_MUTEX(twl_chrdev_mutex);
 static TW_Device_Extension *twl_device_extension_list[TW_MAX_SLOT];
 static unsigned int twl_device_extension_count;
 static int twl_major = -1;
@@ -764,7 +764,7 @@ static long twl_chrdev_ioctl(struct file *file, unsigned int cmd, unsigned long
 	int retval = -EFAULT;
 	void __user *argp = (void __user *)arg;
 
-	lock_kernel();
+	mutex_lock(&twl_chrdev_mutex);
 
 	/* Only let one of these through at a time */
 	if (mutex_lock_interruptible(&tw_dev->ioctl_lock)) {
@@ -861,7 +861,7 @@ out3:
 out2:
 	mutex_unlock(&tw_dev->ioctl_lock);
 out:
-	unlock_kernel();
+	mutex_unlock(&twl_chrdev_mutex);
 	return retval;
 } /* End twl_chrdev_ioctl() */
 
@@ -876,7 +876,6 @@ static int twl_chrdev_open(struct inode *inode, struct file *file)
 		goto out;
 	}
 
-	cycle_kernel_lock();
 	minor_number = iminor(inode);
 	if (minor_number >= twl_device_extension_count)
 		goto out;