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>

2 files changed, 4 insertions, 6 deletions

diff --git a/drivers/scsi/megaraid/megaraid_mm.c b/drivers/scsi/megaraid/megaraid_mm.c
index 41f82f76d884..42770a1e7b8a 100644
--- a/drivers/scsi/megaraid/megaraid_mm.c
+++ b/drivers/scsi/megaraid/megaraid_mm.c
@@ -16,11 +16,12 @@
  */
 #include <linux/sched.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include "megaraid_mm.h"
 
 
 // Entry points for char node driver
+static DEFINE_MUTEX(mraid_mm_mutex);
 static int mraid_mm_open(struct inode *, struct file *);
 static long mraid_mm_unlocked_ioctl(struct file *, uint, unsigned long);
 
@@ -98,7 +99,6 @@ mraid_mm_open(struct inode *inode, struct file *filep)
          */
         if (!capable(CAP_SYS_ADMIN)) return (-EACCES);
 
-        cycle_kernel_lock();
         return 0;
 }
 
@@ -224,9 +224,9 @@ mraid_mm_unlocked_ioctl(struct file *filep, unsigned int cmd,
         int err;
 
         /* inconsistant: mraid_mm_compat_ioctl doesn't take the BKL */
-        lock_kernel();
+        mutex_lock(&mraid_mm_mutex);
         err = mraid_mm_ioctl(filep, cmd, arg);
-        unlock_kernel();
+        mutex_unlock(&mraid_mm_mutex);
 
         return err;
 }
diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index 99e4478c3f3e..c4a595d8d23a 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -33,7 +33,6 @@
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
-#include <linux/smp_lock.h>
 #include <linux/uio.h>
 #include <linux/slab.h>
 #include <asm/uaccess.h>
@@ -3557,7 +3556,6 @@ static void megasas_shutdown(struct pci_dev *pdev)
  */
 static int megasas_mgmt_open(struct inode *inode, struct file *filep)
 {
-        cycle_kernel_lock();
         /*
          * Allow only those users with admin rights
          */