From: Al Viro <viro@ZenIV.linux.org.uk>
To: Joe Eykholt <jeykholt@cisco.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>,
"Sachin P. Sant" <sachinp@in.ibm.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
linux-next@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
linux-scsi <linux-scsi@vger.kernel.org>
Subject: Re: next Feb 13 drivers/scsi/aha1542.ko build break
Date: Fri, 13 Feb 2009 19:34:44 +0000 [thread overview]
Message-ID: <20090213193444.GL28946@ZenIV.linux.org.uk> (raw)
In-Reply-To: <4995C66E.1000800@cisco.com>
On Fri, Feb 13, 2009 at 11:13:50AM -0800, Joe Eykholt wrote:
> > I'm seeing that also. I think that it's this line in aha1542.c:
> >
> > 495: mbo = (scsi2int(mb[mbi].ccbptr) - (SCSI_BUF_PA(&ccb[0]))) / sizeof(struct ccb);
> >
> > since I can comment out the "/ sizeof(struct ccb)" and the driver builds successfully.
> >
> > This may need a patch to use one of the div() macros (?).
>
> In the above case, this problem might not occur if sizeof(struct ccb) happened to
> be a power of 2, since the compiler generates a shift in that case.
> Then later someone could increase the size of the struct and introduce this problem.
The real problem, of course, is that we should _not_ be doing 64bit-division
here, be it by shifts or by __udiv...; if anything, we ought to store the
bus version of HOSTDATA(...)->ccb at the time we'd checked that allocation
got us a small enough address (i.e. after scsi_register()). And store it
in u32.
next prev parent reply other threads:[~2009-02-13 19:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-13 6:55 linux-next: Tree for February 13 Stephen Rothwell
2009-02-13 10:03 ` [S390] next Feb13 build break appldata/built-in.o Sachin P. Sant
2009-02-13 11:28 ` [Patch] [S390] Fix appldata build break with !NET Sachin P. Sant
2009-02-13 13:43 ` Heiko Carstens
2009-02-13 11:44 ` next Feb 13 drivers/scsi/aha1542.ko build break Sachin P. Sant
2009-02-13 18:22 ` Randy Dunlap
2009-02-13 18:52 ` James Bottomley
2009-02-13 20:03 ` Ingo Molnar
2009-02-13 19:13 ` Joe Eykholt
2009-02-13 19:34 ` Al Viro [this message]
2009-02-13 19:35 ` Bart Van Assche
2009-02-13 19:22 ` [PATCH -next] usb: fix ehci printk formats Randy Dunlap
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