* Re: Patch "sd: Disable support for 256 byte/sector disks" has been added to the 4.0-stable tree [not found] ` <556EC8F4.7030507@suse.cz> @ 2015-06-03 13:37 ` James Bottomley 2015-06-03 13:54 ` James Bottomley 0 siblings, 1 reply; 3+ messages in thread From: James Bottomley @ 2015-06-03 13:37 UTC (permalink / raw) To: jslaby@suse.cz Cc: geert@linux-m68k.org, linux-scsi@vger.kernel.org, dmarkh@cfl.rr.com, hare@suse.de, gregkh@linuxfoundation.org, stable@vger.kernel.org, stable-commits@vger.kernel.org On Wed, 2015-06-03 at 11:29 +0200, Jiri Slaby wrote: > On 06/03/2015, 08:35 AM, gregkh@linuxfoundation.org wrote: > > From 74856fbf441929918c49ff262ace9835048e4e6a Mon Sep 17 00:00:00 2001 > > From: Mark Hounschell <dmarkh@cfl.rr.com> > > Date: Wed, 13 May 2015 10:49:09 +0200 > > Subject: sd: Disable support for 256 byte/sector disks > > > > From: Mark Hounschell <dmarkh@cfl.rr.com> > > > > commit 74856fbf441929918c49ff262ace9835048e4e6a upstream. > > > > 256 bytes per sector support has been broken since 2.6.X, > > and no-one stepped up to fix this. > > So disable support for it. > > > > Signed-off-by: Mark Hounschell <dmarkh@cfl.rr.com> > > Signed-off-by: Hannes Reinecke <hare@suse.de> > > Signed-off-by: James Bottomley <JBottomley@Odin.com> > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > > > --- > > drivers/scsi/sd.c | 19 +++++-------------- > > 1 file changed, 5 insertions(+), 14 deletions(-) > > > > --- a/drivers/scsi/sd.c > > +++ b/drivers/scsi/sd.c > > @@ -1624,6 +1624,7 @@ static unsigned int sd_completed_bytes(s > > { > > u64 start_lba = blk_rq_pos(scmd->request); > > u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512); > > + u64 factor = scmd->device->sector_size / 512; > > u64 bad_lba; > > int info_valid; > > /* > > @@ -1645,16 +1646,9 @@ static unsigned int sd_completed_bytes(s > > if (scsi_bufflen(scmd) <= scmd->device->sector_size) > > return 0; > > > > - if (scmd->device->sector_size < 512) { > > - /* only legitimate sector_size here is 256 */ > > - start_lba <<= 1; > > - end_lba <<= 1; > > - } else { > > - /* be careful ... don't want any overflows */ > > - unsigned int factor = scmd->device->sector_size / 512; > > - do_div(start_lba, factor); > > - do_div(end_lba, factor); > > - } > > Hmm, you do 'unsigned int' -> 'u64' switch of factor type here. But this > commit: > commit ef80d1e18b014af08741cf688e3fdda1fb71363f > Author: Geert Uytterhoeven <geert@linux-m68k.org> > Date: Mon Nov 4 10:21:05 2013 +0100 > > [SCSI] sd: Do not call do_div() with a 64-bit divisor > > did the switch in the opposite direction deliberately. > > So why did you do the change, given sector_size is uint? Primarily because no-one spotted the reversal and none of the static checkers warns about it. This is the trivial fix, but we should do something about the checkers. James --- diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 3b2fcb4..3e137dd 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1600,7 +1600,7 @@ static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd) { u64 start_lba = blk_rq_pos(scmd->request); u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512); - u64 factor = scmd->device->sector_size / 512; + unsigned int factor = scmd->device->sector_size / 512; u64 bad_lba; int info_valid; /* ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: Patch "sd: Disable support for 256 byte/sector disks" has been added to the 4.0-stable tree 2015-06-03 13:37 ` Patch "sd: Disable support for 256 byte/sector disks" has been added to the 4.0-stable tree James Bottomley @ 2015-06-03 13:54 ` James Bottomley 2015-06-03 14:37 ` Geert Uytterhoeven 0 siblings, 1 reply; 3+ messages in thread From: James Bottomley @ 2015-06-03 13:54 UTC (permalink / raw) To: jslaby@suse.cz Cc: geert@linux-m68k.org, linux-scsi@vger.kernel.org, dmarkh@cfl.rr.com, hare@suse.de, gregkh@linuxfoundation.org, stable@vger.kernel.org, stable-commits@vger.kernel.org On Wed, 2015-06-03 at 13:37 +0000, James Bottomley wrote: > On Wed, 2015-06-03 at 11:29 +0200, Jiri Slaby wrote: > > On 06/03/2015, 08:35 AM, gregkh@linuxfoundation.org wrote: > > > From 74856fbf441929918c49ff262ace9835048e4e6a Mon Sep 17 00:00:00 2001 > > > From: Mark Hounschell <dmarkh@cfl.rr.com> > > > Date: Wed, 13 May 2015 10:49:09 +0200 > > > Subject: sd: Disable support for 256 byte/sector disks > > > > > > From: Mark Hounschell <dmarkh@cfl.rr.com> > > > > > > commit 74856fbf441929918c49ff262ace9835048e4e6a upstream. > > > > > > 256 bytes per sector support has been broken since 2.6.X, > > > and no-one stepped up to fix this. > > > So disable support for it. > > > > > > Signed-off-by: Mark Hounschell <dmarkh@cfl.rr.com> > > > Signed-off-by: Hannes Reinecke <hare@suse.de> > > > Signed-off-by: James Bottomley <JBottomley@Odin.com> > > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > > > > > --- > > > drivers/scsi/sd.c | 19 +++++-------------- > > > 1 file changed, 5 insertions(+), 14 deletions(-) > > > > > > --- a/drivers/scsi/sd.c > > > +++ b/drivers/scsi/sd.c > > > @@ -1624,6 +1624,7 @@ static unsigned int sd_completed_bytes(s > > > { > > > u64 start_lba = blk_rq_pos(scmd->request); > > > u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512); > > > + u64 factor = scmd->device->sector_size / 512; > > > u64 bad_lba; > > > int info_valid; > > > /* > > > @@ -1645,16 +1646,9 @@ static unsigned int sd_completed_bytes(s > > > if (scsi_bufflen(scmd) <= scmd->device->sector_size) > > > return 0; > > > > > > - if (scmd->device->sector_size < 512) { > > > - /* only legitimate sector_size here is 256 */ > > > - start_lba <<= 1; > > > - end_lba <<= 1; > > > - } else { > > > - /* be careful ... don't want any overflows */ > > > - unsigned int factor = scmd->device->sector_size / 512; > > > - do_div(start_lba, factor); > > > - do_div(end_lba, factor); > > > - } > > > > Hmm, you do 'unsigned int' -> 'u64' switch of factor type here. But this > > commit: > > commit ef80d1e18b014af08741cf688e3fdda1fb71363f > > Author: Geert Uytterhoeven <geert@linux-m68k.org> > > Date: Mon Nov 4 10:21:05 2013 +0100 > > > > [SCSI] sd: Do not call do_div() with a 64-bit divisor > > > > did the switch in the opposite direction deliberately. > > > > So why did you do the change, given sector_size is uint? > > Primarily because no-one spotted the reversal and none of the static > checkers warns about it. > > This is the trivial fix, but we should do something about the checkers. Actually, I think there's no problem: all the architectures now have the correct conversion of the base argument. Author: Andreas Schwab <schwab@linux-m68k.org> Date: Fri Aug 9 15:14:08 2013 +0200 m68k: Truncate base in do_div() Fixed this in m68k, which was the last one, so it looks like there's no issue and ef80d1e18b014af08741cf688e3fdda1fb71363f was pointless. James ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Patch "sd: Disable support for 256 byte/sector disks" has been added to the 4.0-stable tree 2015-06-03 13:54 ` James Bottomley @ 2015-06-03 14:37 ` Geert Uytterhoeven 0 siblings, 0 replies; 3+ messages in thread From: Geert Uytterhoeven @ 2015-06-03 14:37 UTC (permalink / raw) To: James Bottomley Cc: jslaby@suse.cz, linux-scsi@vger.kernel.org, dmarkh@cfl.rr.com, hare@suse.de, gregkh@linuxfoundation.org, stable@vger.kernel.org, stable-commits@vger.kernel.org On Wed, Jun 3, 2015 at 3:54 PM, James Bottomley <James.Bottomley@hansenpartnership.com> wrote: > On Wed, 2015-06-03 at 13:37 +0000, James Bottomley wrote: >> On Wed, 2015-06-03 at 11:29 +0200, Jiri Slaby wrote: >> > On 06/03/2015, 08:35 AM, gregkh@linuxfoundation.org wrote: >> > > From 74856fbf441929918c49ff262ace9835048e4e6a Mon Sep 17 00:00:00 2001 >> > > From: Mark Hounschell <dmarkh@cfl.rr.com> >> > > Date: Wed, 13 May 2015 10:49:09 +0200 >> > > Subject: sd: Disable support for 256 byte/sector disks >> > > >> > > From: Mark Hounschell <dmarkh@cfl.rr.com> >> > > >> > > commit 74856fbf441929918c49ff262ace9835048e4e6a upstream. >> > > >> > > 256 bytes per sector support has been broken since 2.6.X, >> > > and no-one stepped up to fix this. >> > > So disable support for it. >> > > >> > > Signed-off-by: Mark Hounschell <dmarkh@cfl.rr.com> >> > > Signed-off-by: Hannes Reinecke <hare@suse.de> >> > > Signed-off-by: James Bottomley <JBottomley@Odin.com> >> > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> > > >> > > --- >> > > drivers/scsi/sd.c | 19 +++++-------------- >> > > 1 file changed, 5 insertions(+), 14 deletions(-) >> > > >> > > --- a/drivers/scsi/sd.c >> > > +++ b/drivers/scsi/sd.c >> > > @@ -1624,6 +1624,7 @@ static unsigned int sd_completed_bytes(s >> > > { >> > > u64 start_lba = blk_rq_pos(scmd->request); >> > > u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512); >> > > + u64 factor = scmd->device->sector_size / 512; >> > > u64 bad_lba; >> > > int info_valid; >> > > /* >> > > @@ -1645,16 +1646,9 @@ static unsigned int sd_completed_bytes(s >> > > if (scsi_bufflen(scmd) <= scmd->device->sector_size) >> > > return 0; >> > > >> > > - if (scmd->device->sector_size < 512) { >> > > - /* only legitimate sector_size here is 256 */ >> > > - start_lba <<= 1; >> > > - end_lba <<= 1; >> > > - } else { >> > > - /* be careful ... don't want any overflows */ >> > > - unsigned int factor = scmd->device->sector_size / 512; >> > > - do_div(start_lba, factor); >> > > - do_div(end_lba, factor); >> > > - } >> > >> > Hmm, you do 'unsigned int' -> 'u64' switch of factor type here. But this >> > commit: >> > commit ef80d1e18b014af08741cf688e3fdda1fb71363f >> > Author: Geert Uytterhoeven <geert@linux-m68k.org> >> > Date: Mon Nov 4 10:21:05 2013 +0100 >> > >> > [SCSI] sd: Do not call do_div() with a 64-bit divisor >> > >> > did the switch in the opposite direction deliberately. >> > >> > So why did you do the change, given sector_size is uint? >> >> Primarily because no-one spotted the reversal and none of the static >> checkers warns about it. >> >> This is the trivial fix, but we should do something about the checkers. > > Actually, I think there's no problem: all the architectures now have the > correct conversion of the base argument. > > Author: Andreas Schwab <schwab@linux-m68k.org> > Date: Fri Aug 9 15:14:08 2013 +0200 > > m68k: Truncate base in do_div() > > Fixed this in m68k, which was the last one, so it looks like there's no > issue and ef80d1e18b014af08741cf688e3fdda1fb71363f was pointless. FWIW, "[PATCH] mn10300: Truncate base in do_div()" (http://lkml.iu.edu/hypermail/linux/kernel/1308.2/03544.html) hasn't been applied yet. But as mn10300 is little endian, it shouldn't suffer from the bug like m68k did. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-06-03 13:37 ` Patch "sd: Disable support for 256 byte/sector disks" has been added to the 4.0-stable tree James Bottomley
2015-06-03 13:54 ` James Bottomley
2015-06-03 14:37 ` Geert Uytterhoeven
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