From: Andries.Brouwer@cwi.nl
To: linux-kernel@vger.kernel.org
Cc: torvalds@osdl.org
Subject: do_div considered harmful
Date: Mon, 4 Aug 2003 04:03:53 +0200 (MEST) [thread overview]
Message-ID: <UTC200308040203.h7423rv14876.aeb@smtp.cwi.nl> (raw)
Writing this ide capacity patch an hour ago or so
I split off a helper sectors_to_MB() since Erik's recent
patch uses this also.
Now that I compare, he wrote
nativeMb = do_div(nativeMb, 1000000);
to divide nativeMb by 1000000.
Similarly, I find in fs/cifs/inode.c
inode->i_blocks = do_div(findData.NumOfBytes, inode->i_blksize);
So, it seems natural to expect that do_div() gives the quotient.
But it gives the remainder.
(Strange, Erik showed correct output.)
Since the semantics of this object are very unlike that of a C function,
I wonder whether we should write DO_DIV instead, or DO_DIV_AND_REM
to show that a remainder is returned.
Andries
next reply other threads:[~2003-08-04 2:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-04 2:03 Andries.Brouwer [this message]
2003-08-04 2:29 ` do_div considered harmful Andrew Morton
2003-08-05 2:58 ` i_blksize Andries Brouwer
2003-08-05 6:10 ` i_blksize Andrew Morton
2003-08-04 5:54 ` do_div considered harmful Linus Torvalds
2003-08-04 5:31 Steve French
2003-08-04 9:46 Andries.Brouwer
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