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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

8
drivers/scsi/ch.c
View File

@@ -22,7 +22,6 @@
#include <linux/chio.h> /* here are all the ioctls */
#include <linux/mutex.h>
#include <linux/idr.h>
#include <linux/smp_lock.h>
#include <linux/slab.h>
#include <scsi/scsi.h>
@@ -44,6 +43,7 @@ MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(SCSI_CHANGER_MAJOR);
MODULE_ALIAS_SCSI_DEVICE(TYPE_MEDIUM_CHANGER);
static DEFINE_MUTEX(ch_mutex);
static int init = 1;
module_param(init, int, 0444);
MODULE_PARM_DESC(init, \
@@ -581,19 +581,19 @@ ch_open(struct inode *inode, struct file *file)
scsi_changer *ch;
int minor = iminor(inode);
lock_kernel();
mutex_lock(&ch_mutex);
spin_lock(&ch_index_lock);
ch = idr_find(&ch_index_idr, minor);
if (NULL == ch || scsi_device_get(ch->device)) {
spin_unlock(&ch_index_lock);
unlock_kernel();
mutex_unlock(&ch_mutex);
return -ENXIO;
}
spin_unlock(&ch_index_lock);
file->private_data = ch;
unlock_kernel();
mutex_unlock(&ch_mutex);
return 0;
}