Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH 2/7] mtd: autoconvert trivial BKL users to private mutex | Date | Tue, 14 Sep 2010 21:53:37 +0200 |
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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: David Woodhouse <David.Woodhouse@intel.com> Cc: linux-mtd@lists.infradead.org --- drivers/mtd/mtdchar.c | 15 ++++++++------- 1 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c index a825002..5ef4548 100644 --- a/drivers/mtd/mtdchar.c +++ b/drivers/mtd/mtdchar.c @@ -26,7 +26,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/sched.h> -#include <linux/smp_lock.h> +#include <linux/mutex.h> #include <linux/backing-dev.h> #include <linux/compat.h> #include <linux/mount.h> @@ -37,6 +37,7 @@ #include <asm/uaccess.h> #define MTD_INODE_FS_MAGIC 0x11307854 +static DEFINE_MUTEX(mtd_mutex); static struct vfsmount *mtd_inode_mnt __read_mostly; /* @@ -90,7 +91,7 @@ static int mtd_open(struct inode *inode, struct file *file) if ((file->f_mode & FMODE_WRITE) && (minor & 1)) return -EACCES; - lock_kernel(); + mutex_lock(&mtd_mutex); mtd = get_mtd_device(NULL, devnum); if (IS_ERR(mtd)) { @@ -138,7 +139,7 @@ static int mtd_open(struct inode *inode, struct file *file) file->private_data = mfi; out: - unlock_kernel(); + mutex_unlock(&mtd_mutex); return ret; } /* mtd_open */ @@ -866,9 +867,9 @@ static long mtd_unlocked_ioctl(struct file *file, u_int cmd, u_long arg) { int ret; - lock_kernel(); + mutex_lock(&mtd_mutex); ret = mtd_ioctl(file, cmd, arg); - unlock_kernel(); + mutex_unlock(&mtd_mutex); return ret; } @@ -892,7 +893,7 @@ static long mtd_compat_ioctl(struct file *file, unsigned int cmd, void __user *argp = compat_ptr(arg); int ret = 0; - lock_kernel(); + mutex_lock(&mtd_mutex); switch (cmd) { case MEMWRITEOOB32: @@ -927,7 +928,7 @@ static long mtd_compat_ioctl(struct file *file, unsigned int cmd, ret = mtd_ioctl(file, cmd, (unsigned long)argp); } - unlock_kernel(); + mutex_unlock(&mtd_mutex); return ret; } -- 1.7.1
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