While compile btrfs modules on 32bit box, I encounter the following:
WARNING: "__umoddi3" [fs/btrfs/btrfs.ko] undefined!
The WARNING comes from that __btrfs_map_block does not use do_div() for
relative operations, this will cause problems on 32bit box, for values
with "u64" type should use do_div() instead of a direct "%".
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
---
fs/btrfs/volumes.c | 23 +++++++++++++++--------
1 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 41afd50..7b23d0f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3076,16 +3076,19 @@ again:
multi->stripes[i].dev = map->stripes[stripe_index].dev;
if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
- u64 stripes;
- int last_stripe = (stripe_nr_end - 1) %
- map->num_stripes;
+ u64 stripes = stripe_nr_end - 1;
+ int last_stripe = do_div(stripes,
+ map->num_stripes);
int j;
for (j = 0; j < map->num_stripes; j++) {
- if ((stripe_nr_end - 1 - j) %
- map->num_stripes == stripe_index)
+ stripes = stripe_nr_end - 1 - j;
+
+ if (do_div(stripes, map->num_stripes) =+ stripe_index)
break;
}
+
stripes = stripe_nr_end - 1 - j;
do_div(stripes, map->num_stripes);
multi->stripes[i].length = map->stripe_len *
@@ -3100,18 +3103,22 @@ again:
multi->stripes[i].length - stripe_end_offset;
} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
- u64 stripes;
+ u64 stripes = stripe_nr_end - 1;
int j;
int factor = map->num_stripes /
map->sub_stripes;
- int last_stripe = (stripe_nr_end - 1) % factor;
+ int last_stripe = do_div(stripes, factor);
+
last_stripe *= map->sub_stripes;
for (j = 0; j < factor; j++) {
- if ((stripe_nr_end - 1 - j) % factor =+ stripes = stripe_nr_end - 1 -
j;
+
+ if (do_div(stripes, factor) = stripe_index / map->sub_stripes)
break;
}
+
stripes = stripe_nr_end - 1 - j;
do_div(stripes, factor);
multi->stripes[i].length = map->stripe_len *
--
1.6.5.2
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Chris Mason
2011-Mar-31 12:10 UTC
Re: [PATCH] Btrfs: fix compile warning from __btrfs_map_block
Excerpts from liubo''s message of 2011-03-31 05:45:20 -0400:> > While compile btrfs modules on 32bit box, I encounter the following: > > WARNING: "__umoddi3" [fs/btrfs/btrfs.ko] undefined! > > The WARNING comes from that __btrfs_map_block does not use do_div() for > relative operations, this will cause problems on 32bit box, for values > with "u64" type should use do_div() instead of a direct "%".Which kernel tree was this against? I had rebased the for-linus and for-linus-unmerged branch to get rid of it. Sorry for the confusion. -chris> > Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> > --- > fs/btrfs/volumes.c | 23 +++++++++++++++-------- > 1 files changed, 15 insertions(+), 8 deletions(-) > > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 41afd50..7b23d0f 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -3076,16 +3076,19 @@ again: > multi->stripes[i].dev = map->stripes[stripe_index].dev; > > if (map->type & BTRFS_BLOCK_GROUP_RAID0) { > - u64 stripes; > - int last_stripe = (stripe_nr_end - 1) % > - map->num_stripes; > + u64 stripes = stripe_nr_end - 1; > + int last_stripe = do_div(stripes, > + map->num_stripes); > int j; > > for (j = 0; j < map->num_stripes; j++) { > - if ((stripe_nr_end - 1 - j) % > - map->num_stripes == stripe_index) > + stripes = stripe_nr_end - 1 - j; > + > + if (do_div(stripes, map->num_stripes) => + stripe_index) > break; > } > + > stripes = stripe_nr_end - 1 - j; > do_div(stripes, map->num_stripes); > multi->stripes[i].length = map->stripe_len * > @@ -3100,18 +3103,22 @@ again: > multi->stripes[i].length -> stripe_end_offset; > } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) { > - u64 stripes; > + u64 stripes = stripe_nr_end - 1; > int j; > int factor = map->num_stripes / > map->sub_stripes; > - int last_stripe = (stripe_nr_end - 1) % factor; > + int last_stripe = do_div(stripes, factor); > + > last_stripe *= map->sub_stripes; > > for (j = 0; j < factor; j++) { > - if ((stripe_nr_end - 1 - j) % factor => + stripes = stripe_nr_end - 1 - j; > + > + if (do_div(stripes, factor) => stripe_index / map->sub_stripes) > break; > } > + > stripes = stripe_nr_end - 1 - j; > do_div(stripes, factor); > multi->stripes[i].length = map->stripe_len *-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 03/31/2011 08:10 PM, Chris Mason wrote:> Excerpts from liubo''s message of 2011-03-31 05:45:20 -0400: >> While compile btrfs modules on 32bit box, I encounter the following: >> >> WARNING: "__umoddi3" [fs/btrfs/btrfs.ko] undefined! >> >> The WARNING comes from that __btrfs_map_block does not use do_div() for >> relative operations, this will cause problems on 32bit box, for values >> with "u64" type should use do_div() instead of a direct "%". > > Which kernel tree was this against? I had rebased the for-linus and > for-linus-unmerged branch to get rid of it. > > Sorry for the confusion.Ah, it is my fault to neglect the version, I found this warning while compiling the latest for-linus tree (top commit: c1e1f82c56af1a286fd747e809c94628c2ca15fb). thanks, liubo> > -chris > >> Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> >> --- >> fs/btrfs/volumes.c | 23 +++++++++++++++-------- >> 1 files changed, 15 insertions(+), 8 deletions(-) >> >> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c >> index 41afd50..7b23d0f 100644 >> --- a/fs/btrfs/volumes.c >> +++ b/fs/btrfs/volumes.c >> @@ -3076,16 +3076,19 @@ again: >> multi->stripes[i].dev = map->stripes[stripe_index].dev; >> >> if (map->type & BTRFS_BLOCK_GROUP_RAID0) { >> - u64 stripes; >> - int last_stripe = (stripe_nr_end - 1) % >> - map->num_stripes; >> + u64 stripes = stripe_nr_end - 1; >> + int last_stripe = do_div(stripes, >> + map->num_stripes); >> int j; >> >> for (j = 0; j < map->num_stripes; j++) { >> - if ((stripe_nr_end - 1 - j) % >> - map->num_stripes == stripe_index) >> + stripes = stripe_nr_end - 1 - j; >> + >> + if (do_div(stripes, map->num_stripes) =>> + stripe_index) >> break; >> } >> + >> stripes = stripe_nr_end - 1 - j; >> do_div(stripes, map->num_stripes); >> multi->stripes[i].length = map->stripe_len * >> @@ -3100,18 +3103,22 @@ again: >> multi->stripes[i].length ->> stripe_end_offset; >> } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) { >> - u64 stripes; >> + u64 stripes = stripe_nr_end - 1; >> int j; >> int factor = map->num_stripes / >> map->sub_stripes; >> - int last_stripe = (stripe_nr_end - 1) % factor; >> + int last_stripe = do_div(stripes, factor); >> + >> last_stripe *= map->sub_stripes; >> >> for (j = 0; j < factor; j++) { >> - if ((stripe_nr_end - 1 - j) % factor =>> + stripes = stripe_nr_end - 1 - j; >> + >> + if (do_div(stripes, factor) =>> stripe_index / map->sub_stripes) >> break; >> } >> + >> stripes = stripe_nr_end - 1 - j; >> do_div(stripes, factor); >> multi->stripes[i].length = map->stripe_len * > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html