Re: [WATCHDOG] v2.6.18-rc3 patches
From: Alan Cox
Date: Tue Aug 01 2006 - 18:07:09 EST
Ar Maw, 2006-08-01 am 22:09 +0200, ysgrifennodd Wim Van Sebroeck:
> If there are problems with these patches, please let me know.
> If not I will sent them to Linus on sunday.
> +static void wdt_enable(void)
Open, fork and write from both processes. This needs a semaphore
> + if (wdt_clk)
> + clk_set_rate(wdt_clk, 1);
> + /* stop counter, initiate counter reset */
> + __raw_writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
> + /*wait for reset to complete. 100% guarantee event */
> + while (__raw_readl(WDTIM_COUNTER(wdt_base)));
Should have cpu_relax() and really ought to have a timeout in case it
fails. In fact it needs one or a barrier as you are using __raw and that
may not reload if the compiler is overclever.
> +static void wdt_disable(void)
Ditto - open, fork write the close sequence in parallel on both ?
> + wdt_disable(); /*disable for now */
> + set_bit(WDT_DEVICE_INITED, &wdt_status);
> + }
Races an open occuring when misc_register is done and before we hit
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