From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: recent IDE regression Date: Sat, 26 Jul 2008 14:13:38 +0200 Message-ID: <200807261413.38337.bzolnier@gmail.com> References: <20080724.233831.193691312.davem@davemloft.net> <20080725083448.GE8301@fluff.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: Linus Torvalds Cc: Ben Dooks , David Miller , harvey.harrison@gmail.com, linux-ide@kernel.org, linux-kernel@vger.kernel.org List-Id: linux-ide@vger.kernel.org On Friday 25 July 2008, Linus Torvalds wrote: > > On Fri, 25 Jul 2008, Ben Dooks wrote: > > > > personally, i would much prefer to see the loop being less evil > > like: > > > > for (p = s; p < end; p += 2) > > be16_to_cpus((u16 *)p); > > Well, in this case, the code actually depends on 'p' being back at the > start of the buffer by the end of it all, so it would need some more > changes than that. > > But yes, I applied David's patch, but I _also_ suspect that we would be > better off without code that does horrid things like casts and assignments > inside the function arguments. > > So it would be nice to re-code that loop to be more readable. But due to > the reliance of 'p' being 's' after the loop, the minimal patch would be > something like the appended. > > Bartlomiej - take this or not, I'm not going to commit it - I haven't > tested it, nor do I even have any machines that would trigger it. So this > is more a "maybe something like this" than anything else. > > Linus Looks fine and I added it to pata tree but a test+ACK from one of big-endianners would be great. > --- > drivers/ide/ide-iops.c | 8 +++++--- > 1 files changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/ide/ide-iops.c b/drivers/ide/ide-iops.c > index 8aae917..ae03151 100644 > --- a/drivers/ide/ide-iops.c > +++ b/drivers/ide/ide-iops.c > @@ -506,14 +506,16 @@ void ide_fix_driveid (struct hd_driveid *id) > > void ide_fixstring (u8 *s, const int bytecount, const int byteswap) > { > - u8 *p = s, *end = &s[bytecount & ~1]; /* bytecount must be even */ > + u8 *p, *end = &s[bytecount & ~1]; /* bytecount must be even */ > > if (byteswap) { > /* convert from big-endian to host byte order */ > - for (p = end ; p != s;) > - be16_to_cpus((u16 *)(p -= 2)); > + for (p = s ; p != end ; p += 2) > + be16_to_cpus((u16 *) p); > } > + > /* strip leading blanks */ > + p = s; > while (s != end && *s == ' ') > ++s; > /* compress internal blanks and strip trailing blanks */