From mboxrd@z Thu Jan 1 00:00:00 1970 From: Isaac Chanin Subject: Re: Reiser4 SCSI Bug? Date: Sat, 29 Oct 2005 20:35:32 -0400 Message-ID: <43641554.8040500@wpi.edu> References: <2066.130.215.239.65.1130521750.squirrel@webmail.WPI.EDU> <37550.130.215.239.65.1130545649.squirrel@webmail.WPI.EDU> <43639DFA.1020107@namesys.com> <43640228.7080807@wpi.edu> <4364033C.5010200@namesys.com> <436406DF.8070104@wpi.edu> <43643C7E.4080703@namesys.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <43643C7E.4080703@namesys.com> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Hans Reiser Cc: Steve Olivieri , reiserfs-list@namesys.com, Alexander Zarochentcev , vs Hans Reiser wrote: > Isaac Chanin wrote: > > >>Hans Reiser wrote: >> >> >>>It should be not 256, but BIO_MAX_PAGES, yes? Defining limits in two >>>places is bad, yes? >>> >>> >> >>Yeah, I think the code is running into two different limits here. >>Reiser4 wants it to be nr, but limits it to BIO_MAX_PAGES. However, >>apparently, the BIO_MAX_PAGES limit does not take into consideration >>the underlying 256 limit imposed by bio_alloc. >> >>I'm not quite sure if having the two different limits is a bad thing >>in this case, unless BIO_MAX_PAGES can be made to (or is supposed to, >>and there's a bug) take into account the 256 limit. >> >>I suppose the other solution is to not use bio_alloc et al due to the >>256 limit, and find another method that allows values as large as >>BIO_MAX_PAGES, under the current implementation, will grow to. >> >> > > but you said: > > "In any case, BIO_MAX_PAGES is defined to be 256" > > Now I am confused. > > We should use the same macro defining our limit as the underlying layer uses. What macro is that called? > > Right, it would be far better to do min(BIO_MAX_PAGES, ...); rather than using 256 directly. It's defined in include/linux/bio.h which is already included in wander.c.