lkml.org 
[lkml]   [2010]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4/7] ipmi: autoconvert trivial BKL users to private mutex
    Date
    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
    --
    1.7.1


    \
     
     \ /
      Last update: 2010-09-14 21:57    [W:0.027 / U:150.972 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site