Re: [PATCH 14/57] ibmasr: coding style, locking verify

Andrey Panin
2008-05-20T05:56:19Z

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On 140, 05 19, 2008 at 02:06:03PM +0100, Alan Cox wrote:
> From: Alan Cox <alan@redhat.com>
>
> There is a new #if 0 section here which is a suggested fix for the horrible
> PCI hack in the existing code. Would be good if someone with a box that uses
> this device could test it.

Patch looks good, thank you. I'll test it as soon as I can. I need to find
unused IBM server first :)

Unfortunately I don't have suitable machine to test the suggested fix.

> ---
>
> drivers/watchdog/ibmasr.c | 149 ++++++++++++++++++++++++++-------------------
> 1 files changed, 87 insertions(+), 62 deletions(-)
>
>
> diff --git a/drivers/watchdog/ibmasr.c b/drivers/watchdog/ibmasr.c
> index 94155f6..6824bf8 100644
> --- a/drivers/watchdog/ibmasr.c
> +++ b/drivers/watchdog/ibmasr.c
> @@ -19,9 +19,8 @@
> #include <linux/miscdevice.h>
> #include <linux/watchdog.h>
> #include <linux/dmi.h>
> -
> -#include <asm/io.h>
> -#include <asm/uaccess.h>
> +#include <linux/io.h>
> +#include <linux/uaccess.h>
>
>
> enum {
> @@ -70,10 +69,13 @@ static char asr_expect_close;
> static unsigned int asr_type, asr_base, asr_length;
> static unsigned int asr_read_addr, asr_write_addr;
> static unsigned char asr_toggle_mask, asr_disable_mask;
> +static spinlock_t asr_lock;
>
> -static void asr_toggle(void)
> +static void __asr_toggle(void)
> {
> - unsigned char reg = inb(asr_read_addr);
> + unsigned char reg;
> +
> + reg = inb(asr_read_addr);
>
> outb(reg & ~asr_toggle_mask, asr_write_addr);
> reg = inb(asr_read_addr);
> @@ -83,12 +85,21 @@ static void asr_toggle(void)
>
> outb(reg & ~asr_toggle_mask, asr_write_addr);
> reg = inb(asr_read_addr);
> + spin_unlock(&asr_lock);
> +}
> +
> +static void asr_toggle(void)
> +{
> + spin_lock(&asr_lock);
> + __asr_toggle();
> + spin_unlock(&asr_lock);
> }
>
> static void asr_enable(void)
> {
> unsigned char reg;
>
> + spin_lock(&asr_lock);
> if (asr_type == ASMTYPE_TOPAZ) {
> /* asr_write_addr == asr_read_addr */
> reg = inb(asr_read_addr);
> @@ -99,17 +110,21 @@ static void asr_enable(void)
> * First make sure the hardware timer is reset by toggling
> * ASR hardware timer line.
> */
> - asr_toggle();
> + __asr_toggle();
>
> reg = inb(asr_read_addr);
> outb(reg & ~asr_disable_mask, asr_write_addr);
> }
> reg = inb(asr_read_addr);
> + spin_unlock(&asr_lock);
> }
>
> static void asr_disable(void)
> {
> - unsigned char reg = inb(asr_read_addr);
> + unsigned char reg;
> +
> + spin_lock(&asr_lock);
> + reg = inb(asr_read_addr);
>
> if (asr_type == ASMTYPE_TOPAZ)
> /* asr_write_addr == asr_read_addr */
> @@ -122,6 +137,7 @@ static void asr_disable(void)
> outb(reg | asr_disable_mask, asr_write_addr);
> }
> reg = inb(asr_read_addr);
> + spin_unlock(&asr_lock);
> }
>
> static int __init asr_get_base_address(void)
> @@ -133,7 +149,8 @@ static int __init asr_get_base_address(void)
>
> switch (asr_type) {
> case ASMTYPE_TOPAZ:
> - /* SELECT SuperIO CHIP FOR QUERYING (WRITE 0x07 TO BOTH 0x2E and 0x2F) */
> + /* SELECT SuperIO CHIP FOR QUERYING
> + (WRITE 0x07 TO BOTH 0x2E and 0x2F) */
> outb(0x07, 0x2e);
> outb(0x07, 0x2f);
>
> @@ -154,14 +171,26 @@ static int __init asr_get_base_address(void)
>
> case ASMTYPE_JASPER:
> type = "Jaspers ";
> -
> - /* FIXME: need to use pci_config_lock here, but it's not exported */
> +#if 0
> + u32 r;
> + /* Suggested fix */
> + pdev = pci_get_bus_and_slot(0, DEVFN(0x1f, 0));
> + if (pdev == NULL)
> + return -ENODEV;
> + pci_read_config_dword(pdev, 0x58, &r);
> + asr_base = r & 0xFFFE;
> + pci_dev_put(pdev);
> +#else
> + /* FIXME: need to use pci_config_lock here,
> + but it's not exported */
>
> /* spin_lock_irqsave(&pci_config_lock, flags);*/
>
> /* Select the SuperIO chip in the PCI I/O port register */
> outl(0x8000f858, 0xcf8);
>
> + /* BUS 0, Slot 1F, fnc 0, offset 58 */
> +
> /*
> * Read the base address for the SuperIO chip.
> * Only the lower 16 bits are valid, but the address is word
> @@ -170,7 +199,7 @@ static int __init asr_get_base_address(void)
> asr_base = inl(0xcfc) & 0xfffe;
>
> /* spin_unlock_irqrestore(&pci_config_lock, flags);*/
> -
> +#endif
> asr_read_addr = asr_write_addr =
> asr_base + JASPER_ASR_REG_OFFSET;
> asr_toggle_mask = JASPER_ASR_TOGGLE_MASK;
> @@ -241,11 +270,10 @@ static ssize_t asr_write(struct file *file, const char __user *buf,
> return count;
> }
>
> -static int asr_ioctl(struct inode *inode, struct file *file,
> - unsigned int cmd, unsigned long arg)
> +static long asr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> {
> static const struct watchdog_info ident = {
> - .options = WDIOF_KEEPALIVEPING |
> + .options = WDIOF_KEEPALIVEPING |
> WDIOF_MAGICCLOSE,
> .identity = "IBM ASR"
> };
> @@ -254,53 +282,45 @@ static int asr_ioctl(struct inode *inode, struct file *file,
> int heartbeat;
>
> switch (cmd) {
> - case WDIOC_GETSUPPORT:
> - return copy_to_user(argp, &ident, sizeof(ident)) ?
> - -EFAULT : 0;
> -
> - case WDIOC_GETSTATUS:
> - case WDIOC_GETBOOTSTATUS:
> - return put_user(0, p);
> -
> - case WDIOC_KEEPALIVE:
> + case WDIOC_GETSUPPORT:
> + return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
> + case WDIOC_GETSTATUS:
> + case WDIOC_GETBOOTSTATUS:
> + return put_user(0, p);
> + case WDIOC_KEEPALIVE:
> + asr_toggle();
> + return 0;
> + /*
> + * The hardware has a fixed timeout value, so no WDIOC_SETTIMEOUT
> + * and WDIOC_GETTIMEOUT always returns 256.
> + */
> + case WDIOC_GETTIMEOUT:
> + heartbeat = 256;
> + return put_user(heartbeat, p);
> + case WDIOC_SETOPTIONS:
> + {
> + int new_options, retval = -EINVAL;
> + if (get_user(new_options, p))
> + return -EFAULT;
> + if (new_options & WDIOS_DISABLECARD) {
> + asr_disable();
> + retval = 0;
> + }
> + if (new_options & WDIOS_ENABLECARD) {
> + asr_enable();
> asr_toggle();
> - return 0;
> -
> - /*
> - * The hardware has a fixed timeout value, so no WDIOC_SETTIMEOUT
> - * and WDIOC_GETTIMEOUT always returns 256.
> - */
> - case WDIOC_GETTIMEOUT:
> - heartbeat = 256;
> - return put_user(heartbeat, p);
> -
> - case WDIOC_SETOPTIONS: {
> - int new_options, retval = -EINVAL;
> -
> - if (get_user(new_options, p))
> - return -EFAULT;
> -
> - if (new_options & WDIOS_DISABLECARD) {
> - asr_disable();
> - retval = 0;
> - }
> -
> - if (new_options & WDIOS_ENABLECARD) {
> - asr_enable();
> - asr_toggle();
> - retval = 0;
> - }
> -
> - return retval;
> + retval = 0;
> }
> + return retval;
> + }
> + default:
> + return -ENOTTY;
> }
> -
> - return -ENOTTY;
> }
>
> static int asr_open(struct inode *inode, struct file *file)
> {
> - if(test_and_set_bit(0, &asr_is_open))
> + if (test_and_set_bit(0, &asr_is_open))
> return -EBUSY;
>
> asr_toggle();
> @@ -314,7 +334,8 @@ static int asr_release(struct inode *inode, struct file *file)
> if (asr_expect_close == 42)
> asr_disable();
> else {
> - printk(KERN_CRIT PFX "unexpected close, not stopping watchdog!\n");
> + printk(KERN_CRIT PFX
> + "unexpected close, not stopping watchdog!\n");
> asr_toggle();
> }
> clear_bit(0, &asr_is_open);
> @@ -323,12 +344,12 @@ static int asr_release(struct inode *inode, struct file *file)
> }
>
> static const struct file_operations asr_fops = {
> - .owner = THIS_MODULE,
> - .llseek = no_llseek,
> - .write = asr_write,
> - .ioctl = asr_ioctl,
> - .open = asr_open,
> - .release = asr_release,
> + .owner = THIS_MODULE,
> + .llseek = no_llseek,
> + .write = asr_write,
> + .unlocked_ioctl = asr_ioctl,
> + .open = asr_open,
> + .release = asr_release,
> };
>
> static struct miscdevice asr_miscdev = {
> @@ -367,6 +388,8 @@ static int __init ibmasr_init(void)
> if (!asr_type)
> return -ENODEV;
>
> + spin_lock_init(&asr_lock);
> +
> rc = asr_get_base_address();
> if (rc)
> return rc;
> @@ -395,7 +418,9 @@ module_init(ibmasr_init);
> module_exit(ibmasr_exit);
>
> module_param(nowayout, int, 0);
> -MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +MODULE_PARM_DESC(nowayout,
> + "Watchdog cannot be stopped once started (default="
> + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>
> MODULE_DESCRIPTION("IBM Automatic Server Restart driver");
> MODULE_AUTHOR("Andrey Panin");
>
> --
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--
Andrey Panin | Linux and UNIX system administrator
pazke@donpac.ru | PGP key: wwwkeys.pgp.net

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