> -----Original Message----- > From: NeilBrown [mailto:neilb@xxxxxxx] > Sent: Tuesday, December 06, 2011 1:56 AM > To: Hawrylewicz Czarnowski, Przemyslaw > Cc: linux-raid@xxxxxxxxxxxxxxx; Williams, Dan J; Labun, Marcin; > Ciechanowski, Ed > Subject: Re: [PATCH] imsm: fix: does not allow to use invalid chunk size > > On Fri, 25 Nov 2011 13:12:04 +0100 Przemyslaw Czarnowski > <przemyslaw.hawrylewicz.czarnowski@xxxxxxxxx> wrote: > > > Only least significant bit of chunk size provided by user has been > > used in test with OROM capabilities. This way user could pass value > > which is not a power of 2. > > > > Signed-off-by: Przemyslaw Czarnowski > > <przemyslaw.hawrylewicz.czarnowski@xxxxxxxxx> > > --- > > platform-intel.h | 4 +++- > > 1 files changed, 3 insertions(+), 1 deletions(-) > > > > diff --git a/platform-intel.h b/platform-intel.h index > > 6c094d7..99450ba 100644 > > --- a/platform-intel.h > > +++ b/platform-intel.h > > @@ -124,11 +124,13 @@ static inline int imsm_orom_has_raid5(const > > struct imsm_orom *orom) static inline int imsm_orom_has_chunk(const > > struct imsm_orom *orom, int chunk) { > > int fs = ffs(chunk); > > + int orom_chunk_bit; > > > > if (!fs) > > return 0; > > fs--; /* bit num to bit index */ > > - return !!(orom->sss & (1 << (fs - 1))); > > + orom_chunk_bit = (orom->sss & (1 << (fs - 1))); > > + return orom_chunk_bit && 1 << orom_chunk_bit == chunk; > > } > > > > > > applied, thanks. > > However it feels a bit clumsy, though maybe that is just me. > I would use a separate explicit test for "is a power of 2". > ie. > > if (chunk & (chunk-1)) > return 0; /* not a power of 2 */ > fs = ffs(chunk); > return !!(orom->sss & (1 << (fs-2))); > You're right, Please get the one from the bottom of this email then... It is based on your input (~90%) so sign it up and ship:) Moreover previous one is not the right one I wanted to send out... -- Best Regards, Przemyslaw Hawrylewicz-Czarnowski > or something like that. > > NeilBrown -- Subject: [PATCH] fix: imsm: validate strip size - tuned up Neil's proposal seems more reasonable and shows what is really going on here. Signed-off-by: Przemyslaw Czarnowski <przemyslaw.hawrylewicz.czarnowski@xxxxxxxxx> --- platform-intel.h | 7 +++---- 1 files changed, 3 insertions(+), 4 deletions(-) diff --git a/platform-intel.h b/platform-intel.h index 99450ba..c997f1b 100644 --- a/platform-intel.h +++ b/platform-intel.h @@ -124,13 +124,12 @@ static inline int imsm_orom_has_raid5(const struct imsm_orom *orom) static inline int imsm_orom_has_chunk(const struct imsm_orom *orom, int chunk) { int fs = ffs(chunk); - int orom_chunk_bit; - if (!fs) return 0; fs--; /* bit num to bit index */ - orom_chunk_bit = (orom->sss & (1 << (fs - 1))); - return orom_chunk_bit && 1 << orom_chunk_bit == chunk; + if (chunk & (chunk-1)) + return 0; /* not a power of 2 */ + return !!(orom->sss & (1 << (fs - 1))); } -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
