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SubjectRe: [PATCH] sony_pi: Remove the BKL from sonypi_misc_open


On Mon, 19 Oct 2009, Arnd Bergmann wrote:

> On Sunday 18 October 2009, John Kacur wrote:
> > The BKL is in this function because of the BKL pushdown
> > (see commit f8f2c79d594463427f7114cedb1555110d547d89)
> >
> > It is not needed here because the mutex_lock sonypi_device.lock
> > provides the necessary locking.
>
> The driver still uses the BKL in the ioctl function, which can
> probably be removed at the same time.
>
> Arnd <><
>

How does this look? (Version 2 of the patch follows)

From efd07cfcd021b4438d83d383ab81f9b35cb41eb9 Mon Sep 17 00:00:00 2001
From: John Kacur <jkacur@redhat.com>
Date: Sun, 18 Oct 2009 23:49:49 +0200
Subject: [PATCH] sony_pi: Remove the BKL from sonypi_misc_open

The BKL is in this function because of the BKL pushdown
(see commit f8f2c79d594463427f7114cedb1555110d547d89)

It is not needed here because the mutex_lock sonypi_device.lock
provides the necessary locking.

sonpi_misc_ioctl can be converted to unlocked ioctls since it relies on
its own locking (the mutex sonypi_device.lock) and not the bkl

Signed-off-by: John Kacur <jkacur@redhat.com>
---
drivers/char/sonypi.c | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/char/sonypi.c b/drivers/char/sonypi.c
index 8c262aa..593cbb5 100644
--- a/drivers/char/sonypi.c
+++ b/drivers/char/sonypi.c
@@ -50,7 +50,6 @@
#include <linux/err.h>
#include <linux/kfifo.h>
#include <linux/platform_device.h>
-#include <linux/smp_lock.h>

#include <asm/uaccess.h>
#include <asm/io.h>
@@ -902,14 +901,13 @@ static int sonypi_misc_release(struct inode *inode, struct file *file)

static int sonypi_misc_open(struct inode *inode, struct file *file)
{
- lock_kernel();
mutex_lock(&sonypi_device.lock);
/* Flush input queue on first open */
if (!sonypi_device.open_count)
kfifo_reset(sonypi_device.fifo);
sonypi_device.open_count++;
mutex_unlock(&sonypi_device.lock);
- unlock_kernel();
+
return 0;
}

@@ -951,10 +949,10 @@ static unsigned int sonypi_misc_poll(struct file *file, poll_table *wait)
return 0;
}

-static int sonypi_misc_ioctl(struct inode *ip, struct file *fp,
+static long sonypi_misc_ioctl(struct file *fp,
unsigned int cmd, unsigned long arg)
{
- int ret = 0;
+ long ret = 0;
void __user *argp = (void __user *)arg;
u8 val8;
u16 val16;
@@ -1070,7 +1068,7 @@ static const struct file_operations sonypi_misc_fops = {
.open = sonypi_misc_open,
.release = sonypi_misc_release,
.fasync = sonypi_misc_fasync,
- .ioctl = sonypi_misc_ioctl,
+ .unlocked_ioctl = sonypi_misc_ioctl,
};

static struct miscdevice sonypi_misc_device = {
--
1.6.0.6



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