| Message ID | 20200507023526.221574-1-damien.lemoal@wdc.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 108e36f0d8bf91839613d8053a6d1354965801b0 |
| Headers | show |
| Series | scsi_debug: Fix compilation error on 32bits arch | expand |
Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Hi Damien, On Thu, 7 May 2020, Damien Le Moal wrote: > Allowing a non-power-of-2 zone size forces the use of direct division > operations of 64bits sector values to obtain a zone number or number of > zones. Doing so without using do_div() leads to compilation errors on > 32bits architecture. As reported by noreply@ellerman.id.au for m68k-allmodconfig: ERROR: modpost: "__udivdi3" [drivers/scsi/scsi_debug.ko] undefined! > Devices with a zone size that is not a power of 2 do not exist today so > allowing their emulation is of limited interest, as the sd driver will > not support them anyway. So to fix this compilation error, instead of > using do_div() for sector values divisions, simply disallow zone size > values that are not a power of 2 value, allowing to use bitshift for > divisions in all cases. > > Fixes: 98e0a689868c ("scsi: scsi_debug: Add zone_size_mb module parameter") > Fixes: f0d1cf9378bd ("scsi: scsi_debug: Add ZBC zone commands") > Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> And your patch fixes that, so Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> 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
On Thu, 7 May 2020 11:35:26 +0900, Damien Le Moal wrote: > Allowing a non-power-of-2 zone size forces the use of direct division > operations of 64bits sector values to obtain a zone number or number of > zones. Doing so without using do_div() leads to compilation errors on > 32bits architecture. > > Devices with a zone size that is not a power of 2 do not exist today so > allowing their emulation is of limited interest, as the sd driver will > not support them anyway. So to fix this compilation error, instead of > using do_div() for sector values divisions, simply disallow zone size > values that are not a power of 2 value, allowing to use bitshift for > divisions in all cases. Applied to 5.8/scsi-queue, thanks! [1/1] scsi: scsi_debug: Disallow zone sizes that are not powers of 2 https://git.kernel.org/mkp/scsi/c/108e36f0d8bf
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index d3ea16f3c12e..105e563d87b4 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -2657,13 +2657,7 @@ static inline bool sdebug_dev_is_zoned(struct sdebug_dev_info *devip) static struct sdeb_zone_state *zbc_zone(struct sdebug_dev_info *devip, unsigned long long lba) { - unsigned int zno; - - if (devip->zsize_shift) - zno = lba >> devip->zsize_shift; - else - zno = lba / devip->zsize; - return &devip->zstate[zno]; + return &devip->zstate[lba >> devip->zsize_shift]; } static inline bool zbc_zone_is_conv(struct sdeb_zone_state *zsp) @@ -4306,7 +4300,7 @@ static int resp_report_zones(struct scsi_cmnd *scp, return check_condition_result; } - max_zones = devip->nr_zones - zs_lba / devip->zsize; + max_zones = devip->nr_zones - (zs_lba >> devip->zsize_shift); rep_max_zones = min((alloc_len - 64) >> ilog2(RZONES_DESC_HD), max_zones); @@ -4826,6 +4820,10 @@ static int sdebug_device_create_zones(struct sdebug_dev_info *devip) return -EINVAL; } } else { + if (!is_power_of_2(sdeb_zbc_zone_size_mb)) { + pr_err("Zone size is not a power of 2\n"); + return -EINVAL; + } devip->zsize = (sdeb_zbc_zone_size_mb * SZ_1M) >> ilog2(sdebug_sector_size); if (devip->zsize >= capacity) { @@ -4834,8 +4832,7 @@ static int sdebug_device_create_zones(struct sdebug_dev_info *devip) } } - if (is_power_of_2(devip->zsize)) - devip->zsize_shift = ilog2(devip->zsize); + devip->zsize_shift = ilog2(devip->zsize); devip->nr_zones = (capacity + devip->zsize - 1) >> devip->zsize_shift; if (sdeb_zbc_nr_conv >= devip->nr_zones) {
Allowing a non-power-of-2 zone size forces the use of direct division operations of 64bits sector values to obtain a zone number or number of zones. Doing so without using do_div() leads to compilation errors on 32bits architecture. Devices with a zone size that is not a power of 2 do not exist today so allowing their emulation is of limited interest, as the sd driver will not support them anyway. So to fix this compilation error, instead of using do_div() for sector values divisions, simply disallow zone size values that are not a power of 2 value, allowing to use bitshift for divisions in all cases. Fixes: 98e0a689868c ("scsi: scsi_debug: Add zone_size_mb module parameter") Fixes: f0d1cf9378bd ("scsi: scsi_debug: Add ZBC zone commands") Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> --- drivers/scsi/scsi_debug.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-)