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    SubjectRe: [PATCH 4/7] ipmi: autoconvert trivial BKL users to private mutex
    This patch is good with me.

    Acked-by: Corey Minyard <cminyard@mvista.com>

    On 09/14/2010 02:53 PM, Arnd Bergmann wrote:
    > 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: Corey Minyard<minyard@acm.org>
    > Cc: openipmi-developer@lists.sourceforge.net
    > ---
    > drivers/char/ipmi/ipmi_devintf.c | 14 +++++++-------
    > drivers/char/ipmi/ipmi_watchdog.c | 8 ++++----
    > 2 files changed, 11 insertions(+), 11 deletions(-)
    >
    > diff --git a/drivers/char/ipmi/ipmi_devintf.c b/drivers/char/ipmi/ipmi_devintf.c
    > index d8ec92a..44833de 100644
    > --- a/drivers/char/ipmi/ipmi_devintf.c
    > +++ b/drivers/char/ipmi/ipmi_devintf.c
    > @@ -44,7 +44,6 @@
    > #include<linux/init.h>
    > #include<linux/device.h>
    > #include<linux/compat.h>
    > -#include<linux/smp_lock.h>
    >
    > struct ipmi_file_private
    > {
    > @@ -59,6 +58,7 @@ struct ipmi_file_private
    > unsigned int default_retry_time_ms;
    > };
    >
    > +static DEFINE_MUTEX(ipmi_mutex);
    > static void file_receive_handler(struct ipmi_recv_msg *msg,
    > void *handler_data)
    > {
    > @@ -102,9 +102,9 @@ static int ipmi_fasync(int fd, struct file *file, int on)
    > struct ipmi_file_private *priv = file->private_data;
    > int result;
    >
    > - lock_kernel(); /* could race against open() otherwise */
    > + mutex_lock(&ipmi_mutex); /* could race against open() otherwise */
    > result = fasync_helper(fd, file, on,&priv->fasync_queue);
    > - unlock_kernel();
    > + mutex_unlock(&ipmi_mutex);
    >
    > return (result);
    > }
    > @@ -125,7 +125,7 @@ static int ipmi_open(struct inode *inode, struct file *file)
    > if (!priv)
    > return -ENOMEM;
    >
    > - lock_kernel();
    > + mutex_lock(&ipmi_mutex);
    > priv->file = file;
    >
    > rv = ipmi_create_user(if_num,
    > @@ -150,7 +150,7 @@ static int ipmi_open(struct inode *inode, struct file *file)
    > priv->default_retry_time_ms = 0;
    >
    > out:
    > - unlock_kernel();
    > + mutex_unlock(&ipmi_mutex);
    > return rv;
    > }
    >
    > @@ -639,9 +639,9 @@ static long ipmi_unlocked_ioctl(struct file *file,
    > {
    > int ret;
    >
    > - lock_kernel();
    > + mutex_lock(&ipmi_mutex);
    > ret = ipmi_ioctl(file, cmd, data);
    > - unlock_kernel();
    > + mutex_unlock(&ipmi_mutex);
    >
    > return ret;
    > }
    > diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
    > index 654d566..ed10b74 100644
    > --- a/drivers/char/ipmi/ipmi_watchdog.c
    > +++ b/drivers/char/ipmi/ipmi_watchdog.c
    > @@ -35,7 +35,7 @@
    > #include<linux/moduleparam.h>
    > #include<linux/ipmi.h>
    > #include<linux/ipmi_smi.h>
    > -#include<linux/smp_lock.h>
    > +#include<linux/mutex.h>
    > #include<linux/watchdog.h>
    > #include<linux/miscdevice.h>
    > #include<linux/init.h>
    > @@ -149,6 +149,7 @@
    > #define WDIOC_GET_PRETIMEOUT _IOW(WATCHDOG_IOCTL_BASE, 22, int)
    > #endif
    >
    > +static DEFINE_MUTEX(ipmi_watchdog_mutex);
    > static int nowayout = WATCHDOG_NOWAYOUT;
    >
    > static ipmi_user_t watchdog_user;
    > @@ -748,9 +749,9 @@ static long ipmi_unlocked_ioctl(struct file *file,
    > {
    > int ret;
    >
    > - lock_kernel();
    > + mutex_lock(&ipmi_watchdog_mutex);
    > ret = ipmi_ioctl(file, cmd, arg);
    > - unlock_kernel();
    > + mutex_unlock(&ipmi_watchdog_mutex);
    >
    > return ret;
    > }
    > @@ -844,7 +845,6 @@ static int ipmi_open(struct inode *ino, struct file *filep)
    > if (test_and_set_bit(0,&ipmi_wdog_open))
    > return -EBUSY;
    >
    > - cycle_kernel_lock();
    >
    > /*
    > * Don't start the timer now, let it start on the
    >



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