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Message-ID: <20080804165407.15222.90326.stgit@localhost.localdomain>
Date: Mon, 04 Aug 2008 17:54:46 +0100
From: Alan Cox <alan@...rguk.ukuu.org.uk>
To: torvalds@...l.org, linux-kernel@...r.kernel.org, wim@...ana.be
Subject: [PATCH 3/6] Locking and coding style
Kill off use of semaphores.
Fix ioctl races and locking holes.
From: Alan Cox <alan@...hat.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Alan Cox <alan@...hat.com>
---
drivers/watchdog/s3c2410_wdt.c | 148 ++++++++++++++++++++++------------------
1 files changed, 80 insertions(+), 68 deletions(-)
diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 98532c0..97b4a2e 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -46,9 +46,8 @@
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
-
-#include <asm/uaccess.h>
-#include <asm/io.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
#include <asm/arch/map.h>
@@ -65,8 +64,8 @@
static int nowayout = WATCHDOG_NOWAYOUT;
static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;
-static int soft_noboot = 0;
-static int debug = 0;
+static int soft_noboot;
+static int debug;
module_param(tmr_margin, int, 0);
module_param(tmr_atboot, int, 0);
@@ -74,24 +73,23 @@ module_param(nowayout, int, 0);
module_param(soft_noboot, int, 0);
module_param(debug, int, 0);
-MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
-
-MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
-
-MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
-
+MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default="
+ __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
+MODULE_PARM_DESC(tmr_atboot,
+ "Watchdog is started at boot time if set to 1, default="
+ __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
-
MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
typedef enum close_state {
CLOSE_STATE_NOT,
- CLOSE_STATE_ALLOW=0x4021
+ CLOSE_STATE_ALLOW = 0x4021
} close_state_t;
-static DECLARE_MUTEX(open_lock);
-
+static unsigned long open_lock;
static struct device *wdt_dev; /* platform device attached to */
static struct resource *wdt_mem;
static struct resource *wdt_irq;
@@ -99,38 +97,58 @@ static struct clk *wdt_clock;
static void __iomem *wdt_base;
static unsigned int wdt_count;
static close_state_t allow_close;
+static DEFINE_SPINLOCK(wdt_lock);
/* watchdog control routines */
#define DBG(msg...) do { \
if (debug) \
printk(KERN_INFO msg); \
- } while(0)
+ } while (0)
/* functions */
-static int s3c2410wdt_keepalive(void)
+static void s3c2410wdt_keepalive(void)
{
+ spin_lock(&wdt_lock);
writel(wdt_count, wdt_base + S3C2410_WTCNT);
- return 0;
+ spin_unlock(&wdt_lock);
}
-static int s3c2410wdt_stop(void)
+static void __s3c2410wdt_stop(void)
{
unsigned long wtcon;
+ spin_lock(&wdt_lock);
wtcon = readl(wdt_base + S3C2410_WTCON);
wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
writel(wtcon, wdt_base + S3C2410_WTCON);
+ spin_unlock(&wdt_lock);
+}
- return 0;
+static void __s3c2410wdt_stop(void)
+{
+ unsigned long wtcon;
+
+ wtcon = readl(wdt_base + S3C2410_WTCON);
+ wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
+ writel(wtcon, wdt_base + S3C2410_WTCON);
+}
+
+static void s3c2410wdt_stop(void)
+{
+ spin_lock(&wdt_lock);
+ __s3c2410wdt_stop();
+ spin_unlock(&wdt_lock);
}
-static int s3c2410wdt_start(void)
+static void s3c2410wdt_start(void)
{
unsigned long wtcon;
- s3c2410wdt_stop();
+ spin_lock(&wdt_lock);
+
+ __s3c2410wdt_stop();
wtcon = readl(wdt_base + S3C2410_WTCON);
wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
@@ -149,6 +167,7 @@ static int s3c2410wdt_start(void)
writel(wdt_count, wdt_base + S3C2410_WTDAT);
writel(wdt_count, wdt_base + S3C2410_WTCNT);
writel(wtcon, wdt_base + S3C2410_WTCON);
+ spin_unlock(&wdt_lock);
return 0;
}
@@ -211,7 +230,7 @@ static int s3c2410wdt_set_heartbeat(int timeout)
static int s3c2410wdt_open(struct inode *inode, struct file *file)
{
- if(down_trylock(&open_lock))
+ if (test_and_set_bit(0, &open_lock))
return -EBUSY;
if (nowayout)
@@ -231,15 +250,14 @@ static int s3c2410wdt_release(struct inode *inode, struct file *file)
* Lock it in if it's a module and we set nowayout
*/
- if (allow_close == CLOSE_STATE_ALLOW) {
+ if (allow_close == CLOSE_STATE_ALLOW)
s3c2410wdt_stop();
- } else {
+ else {
dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");
s3c2410wdt_keepalive();
}
-
allow_close = CLOSE_STATE_NOT;
- up(&open_lock);
+ clear_bit(0, &open_lock);
return 0;
}
@@ -249,7 +267,7 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
/*
* Refresh the timer.
*/
- if(len) {
+ if (len) {
if (!nowayout) {
size_t i;
@@ -265,7 +283,6 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
allow_close = CLOSE_STATE_ALLOW;
}
}
-
s3c2410wdt_keepalive();
}
return len;
@@ -273,48 +290,41 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
-static struct watchdog_info s3c2410_wdt_ident = {
+static const struct watchdog_info s3c2410_wdt_ident = {
.options = OPTIONS,
.firmware_version = 0,
.identity = "S3C2410 Watchdog",
};
-static int s3c2410wdt_ioctl(struct inode *inode, struct file *file,
- unsigned int cmd, unsigned long arg)
+static long s3c2410wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
int new_margin;
switch (cmd) {
- default:
- return -ENOTTY;
-
- case WDIOC_GETSUPPORT:
- return copy_to_user(argp, &s3c2410_wdt_ident,
- sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
-
- case WDIOC_GETSTATUS:
- case WDIOC_GETBOOTSTATUS:
- return put_user(0, p);
-
- case WDIOC_KEEPALIVE:
- s3c2410wdt_keepalive();
- return 0;
-
- case WDIOC_SETTIMEOUT:
- if (get_user(new_margin, p))
- return -EFAULT;
-
- if (s3c2410wdt_set_heartbeat(new_margin))
- return -EINVAL;
-
- s3c2410wdt_keepalive();
- return put_user(tmr_margin, p);
-
- case WDIOC_GETTIMEOUT:
- return put_user(tmr_margin, p);
+ default:
+ return -ENOTTY;
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &s3c2410_wdt_ident,
+ sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+ case WDIOC_KEEPALIVE:
+ s3c2410wdt_keepalive();
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_margin, p))
+ return -EFAULT;
+ if (s3c2410wdt_set_heartbeat(new_margin))
+ return -EINVAL;
+ s3c2410wdt_keepalive();
+ return put_user(tmr_margin, p);
+ case WDIOC_GETTIMEOUT:
+ return put_user(tmr_margin, p);
}
}
@@ -324,7 +334,7 @@ static const struct file_operations s3c2410wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = s3c2410wdt_write,
- .ioctl = s3c2410wdt_ioctl,
+ .unlocked_ioctl = s3c2410wdt_ioctl,
.open = s3c2410wdt_open,
.release = s3c2410wdt_release,
};
@@ -411,14 +421,15 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
* not, try the default value */
if (s3c2410wdt_set_heartbeat(tmr_margin)) {
- started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
+ started = s3c2410wdt_set_heartbeat(
+ CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
- if (started == 0) {
- dev_info(dev,"tmr_margin value out of range, default %d used\n",
+ if (started == 0)
+ dev_info(dev,
+ "tmr_margin value out of range, default %d used\n",
CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
- } else {
+ else
dev_info(dev, "default timer value is out of range, cannot start\n");
- }
}
ret = misc_register(&s3c2410wdt_miscdev);
@@ -447,7 +458,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
(wtcon & S3C2410_WTCON_ENABLE) ? "" : "in",
(wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
(wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
-
+
return 0;
err_clk:
@@ -487,7 +498,7 @@ static int s3c2410wdt_remove(struct platform_device *dev)
static void s3c2410wdt_shutdown(struct platform_device *dev)
{
- s3c2410wdt_stop();
+ s3c2410wdt_stop();
}
#ifdef CONFIG_PM
@@ -540,7 +551,8 @@ static struct platform_driver s3c2410wdt_driver = {
};
-static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
+static char banner[] __initdata =
+ KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
static int __init watchdog_init(void)
{
--
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