Re: [PATCH 07/12] cris: autoconvert trivial BKL users to private mutex

Previous thread: [PATCH 11/12] ipmi: autoconvert trivial BKL users to private mutex by Arnd Bergmann on Sunday, July 11, 2010 - 2:19 pm. (1 message)

Next thread: [PATCH 10/12] mac: autoconvert trivial BKL users to private mutex by Arnd Bergmann on Sunday, July 11, 2010 - 2:19 pm. (1 message)
From: Arnd Bergmann
Date: Sunday, July 11, 2010 - 2:18 pm

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-cris-kernel@axis.com
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
---
 arch/cris/arch-v10/drivers/eeprom.c    |    2 --
 arch/cris/arch-v10/drivers/i2c.c       |    2 --
 arch/cris/arch-v32/drivers/cryptocop.c |    2 --
 arch/cris/arch-v32/drivers/i2c.c       |   12 ++++++------
 4 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/arch/cris/arch-v10/drivers/eeprom.c b/arch/cris/arch-v10/drivers/eeprom.c
index c340550..5047a33 100644
--- a/arch/cris/arch-v10/drivers/eeprom.c
+++ b/arch/cris/arch-v10/drivers/eeprom.c
@@ -28,7 +28,6 @@
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
-#include <linux/smp_lock.h>
 #include <linux/wait.h>
 #include <asm/uaccess.h>
 ...
From: Jesper Nilsson
Date: Friday, July 30, 2010 - 10:20 am

Thanks, added to the cris-tree.

/^JN - Jesper Nilsson
-- 
               Jesper Nilsson -- jesper.nilsson@axis.com
--

Previous thread: [PATCH 11/12] ipmi: autoconvert trivial BKL users to private mutex by Arnd Bergmann on Sunday, July 11, 2010 - 2:19 pm. (1 message)

Next thread: [PATCH 10/12] mac: autoconvert trivial BKL users to private mutex by Arnd Bergmann on Sunday, July 11, 2010 - 2:19 pm. (1 message)