Messages in this thread | | | Date | Thu, 24 Feb 2011 12:37:56 +0100 | From | Marc Koschewski <> | Subject | Re: [PATCH 1/1]mmc: fix division by zero when calculate mmc erase time |
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Hi,
* Chuanxiao Dong <chuanxiao.dong@intel.com> [2011-02-24 19:18:01 +0800]:
> Since if clock gating feature is enabled, the clock frequency may be zero when > host clock is gated. In such scenario, mmc_set_mmc_erase_timeout() may have a > division by zero bug. > > So this patch used mmc_host_clk_rate() to fix this. > > Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com> > --- > drivers/mmc/core/core.c | 10 ++++++++-- > 1 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > index 34a7e8c..12d0eb8 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -1201,8 +1201,14 @@ static void mmc_set_mmc_erase_timeout(struct mmc_card *card, > * less but not that much less, so fudge it by multiplying by 2. > */ > timeout_clks <<= 1; > - timeout_us += (timeout_clks * 1000) / > - (card->host->ios.clock / 1000); > + > + /* > + * at this moment, host controller maybe clock gated, so make > + * sure we can get a correct host clock freq. > + */ > + if (mmc_host_clk_rate(card->host)) > + timeout_us += (timeout_clks * 1000) / > + (mmc_host_clk_rate(card->host) / 1000);
Why don't you just reuse mmc_host_clk_rate()'s result instead of calling it twice?
Cheers, Marc
> > erase_timeout = timeout_us / 1000; > > -- > 1.6.6.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > >
-- Marc Koschewski
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