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scsi: autoconvert trivial BKL users to private mutex

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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>
This commit is contained in:
Arnd Bergmann
2010-06-02 14:28:52 +02:00
parent 49553c2ef8
commit c45d15d24e
16 changed files with 86 additions and 85 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/scsi/sg.c
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@@ -49,7 +49,7 @@ static int sg_version_num = 30534; /* 2 digits for each component */
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/blktrace_api.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include "scsi.h"
#include <scsi/scsi_dbg.h>
@@ -103,6 +103,8 @@ static int scatter_elem_sz_prev = SG_SCATTER_SZ;
static int sg_add(struct device *, struct class_interface *);
static void sg_remove(struct device *, struct class_interface *);
static DEFINE_MUTEX(sg_mutex);
static DEFINE_IDR(sg_index_idr);
static DEFINE_RWLOCK(sg_index_lock); /* Also used to lock
file descriptor list for device */
@@ -229,7 +231,7 @@ sg_open(struct inode *inode, struct file *filp)
int res;
int retval;
lock_kernel();
mutex_lock(&sg_mutex);
nonseekable_open(inode, filp);
SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
sdp = sg_get_dev(dev);
@@ -314,7 +316,7 @@ sdp_put:
sg_put:
if (sdp)
sg_put_dev(sdp);
unlock_kernel();
mutex_unlock(&sg_mutex);
return retval;
}
@@ -1092,9 +1094,9 @@ sg_unlocked_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
{
int ret;
lock_kernel();
mutex_lock(&sg_mutex);
ret = sg_ioctl(filp, cmd_in, arg);
unlock_kernel();
mutex_unlock(&sg_mutex);
return ret;
}