Messages in this thread | | | Date | Sun, 12 Aug 2007 03:54:28 +0200 | From | Rene Herman <> | Subject | Re: [PATCH] Re: cciss: warning: right shift count >= width of type |
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On 08/12/2007 03:25 AM, Rene Herman wrote:
> On 08/12/2007 02:56 AM, Jesper Juhl wrote: > >> (whoops, forgot to add maintainer to Cc - now added) > > Ehm... too late...
Useless followup though -- hp.com rejects me as it feels the SPF neutral results gmail sends due to me not using the gmail SMTP server and/or web interface is something it wants to listen to.
I see you are @gmail as well, which depending on how you use it might mean your are also not able to reach @hp. If anyone can get HP to fix their mail setup, that'd be useful.
Rene.
> >> On 12/08/07, Jesper Juhl <jesper.juhl@gmail.com> wrote: >>> Hi, >>> >>> I've been building some randconfig kernels lately and I've noticed >>> this in a few builds : >>> >>> drivers/block/cciss.c:2614: warning: right shift count >= width of type >>> drivers/block/cciss.c:2615: warning: right shift count >= width of type >>> drivers/block/cciss.c:2616: warning: right shift count >= width of type >>> >>> The code in question is this : >>> >>> static void do_cciss_request(struct request_queue *q) >>> { >>> ... >>> sector_t start_blk; >>> ... >>> c->Request.CDB[2]= (start_blk >> 56) & >>> 0xff; //MSB >>> c->Request.CDB[3]= (start_blk >> 48) & 0xff; >>> c->Request.CDB[4]= (start_blk >> 40) & 0xff; >>> ... >>> } >>> >>> >>> The problem stems from these lines in include/linux/types.h : >>> ... >>> #ifdef CONFIG_LBD >>> typedef u64 sector_t; >>> #else >>> typedef unsigned long sector_t; >>> #endif >>> ... >>> >>> So on a 32bit arch without CONFIG_LBD, sector_t is going to be 32 >>> bits wide. >>> Thus it seems gcc is absolutely right in complaining about those >>> 56, 48 & 40 bit shifts, since they are indeed wider than the type >>> in the "!CONFIG_LBD on a 32bit arch" case. >>> >>> >>> I must admit that I have no idear what the proper way to deal with >>> that is, so I'll just report it so hopefully someone else can fix it. >>> >>> By the way; I'm building current Linus git tree, head at commit >>> ac07860264bd2b18834d3fa3be47032115524cea > > Well, given that it's explicitly treating start_blk as a 64-bit value, > the proper fix is probably to cast start_blk to an actual (guaranteed) > 64-bit value. Untested, uncompiled, and someone else may disagree: > > Rene. >
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