Building on tilepro revealed two minor portability issues: the
blocklayout.c file used prefetchw() without #include <linux/prefetch.h>,
and the nfs4filelayout.c file used do_div() on an s64 not a u64.
This change fixes those two issues so the NFS code builds on tilepro.
Signed-off-by: Chris Metcalf <[email protected]>
---
fs/nfs/blocklayout/blocklayout.c | 1 +
fs/nfs/nfs4filelayout.c | 6 +++---
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index e56564d..9561c8f 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -36,6 +36,7 @@
#include <linux/namei.h>
#include <linux/bio.h> /* struct bio */
#include <linux/buffer_head.h> /* various write calls */
+#include <linux/prefetch.h>
#include "blocklayout.h"
diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index e8915d4..6976a72 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -48,13 +48,13 @@ filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg,
loff_t offset)
{
u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count;
- u64 tmp;
+ u64 tmp, uoff;
offset -= flseg->pattern_offset;
- tmp = offset;
+ tmp = uoff = offset;
do_div(tmp, stripe_width);
- return tmp * flseg->stripe_unit + do_div(offset, flseg->stripe_unit);
+ return tmp * flseg->stripe_unit + do_div(uoff, flseg->stripe_unit);
}
/* This function is used by the layout driver to calculate the
--
1.6.5.2
On Thu, Aug 11, 2011 at 1:56 AM, Chris Metcalf <[email protected]> wrote:
> Building on tilepro revealed two minor portability issues: the
> blocklayout.c file used prefetchw() without #include <linux/prefetch.h>,
> and the nfs4filelayout.c file used do_div() on an s64 not a u64.
> This change fixes those two issues so the NFS code builds on tilepro.
>
> Signed-off-by: Chris Metcalf <[email protected]>
> ---
> fs/nfs/blocklayout/blocklayout.c | 1 +
> fs/nfs/nfs4filelayout.c | 6 +++---
> 2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
> index e56564d..9561c8f 100644
> --- a/fs/nfs/blocklayout/blocklayout.c
> +++ b/fs/nfs/blocklayout/blocklayout.c
> @@ -36,6 +36,7 @@
> #include <linux/namei.h>
> #include <linux/bio.h> /* struct bio */
> #include <linux/buffer_head.h> /* various write calls */
> +#include <linux/prefetch.h>
This is already fixed in Trond's nfs-for-next branch by commit 88c9e4219.
>
> #include "blocklayout.h"
>
> diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
> index e8915d4..6976a72 100644
> --- a/fs/nfs/nfs4filelayout.c
> +++ b/fs/nfs/nfs4filelayout.c
> @@ -48,13 +48,13 @@ filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg,
> loff_t offset)
> {
> u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count;
> - u64 tmp;
> + u64 tmp, uoff;
>
> offset -= flseg->pattern_offset;
> - tmp = offset;
> + tmp = uoff = offset;
> do_div(tmp, stripe_width);
>
> - return tmp * flseg->stripe_unit + do_div(offset, flseg->stripe_unit);
> + return tmp * flseg->stripe_unit + do_div(uoff, flseg->stripe_unit);
> }
>
> /* This function is used by the layout driver to calculate the
> --
> 1.6.5.2
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
Thanks,
-Bergwolf
On 08/11/2011 06:26 AM, Chris Metcalf wrote:
>
> You can't use a cast with do_div() or you get errors about non-lvalues.
>
> And the context here is that we want the remainder, not the divided result,
> so we'd need a temporary variable anyway if we were going to use a routine
> from math64.h, presumably div_u64_rem(). But that's just an inline wrapper
> around do_div() anyway, so it's no more efficient, and not obviously any
> less "cluttered" in the source code here. The original code author (who
> I'm adding belatedly to this email) may have a stronger opinion.
>
> I'm not the author or maintainer of this code, I just want it to compile
> without warning on 32-bit architectures :-)
>
Still, if you fix it do it properly by using, as you said, div_u64_rem().
It's what needs to be used with u64 types.
Thanks
Boaz
On 08/10/2011 10:56 AM, Chris Metcalf wrote:
> Building on tilepro revealed two minor portability issues: the
> blocklayout.c file used prefetchw() without #include <linux/prefetch.h>,
> and the nfs4filelayout.c file used do_div() on an s64 not a u64.
> This change fixes those two issues so the NFS code builds on tilepro.
>
> Signed-off-by: Chris Metcalf <[email protected]>
> ---
> fs/nfs/blocklayout/blocklayout.c | 1 +
> fs/nfs/nfs4filelayout.c | 6 +++---
> 2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
> index e56564d..9561c8f 100644
> --- a/fs/nfs/blocklayout/blocklayout.c
> +++ b/fs/nfs/blocklayout/blocklayout.c
> @@ -36,6 +36,7 @@
> #include <linux/namei.h>
> #include <linux/bio.h> /* struct bio */
> #include <linux/buffer_head.h> /* various write calls */
> +#include <linux/prefetch.h>
>
> #include "blocklayout.h"
>
> diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
> index e8915d4..6976a72 100644
> --- a/fs/nfs/nfs4filelayout.c
> +++ b/fs/nfs/nfs4filelayout.c
> @@ -48,13 +48,13 @@ filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg,
> loff_t offset)
> {
> u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count;
> - u64 tmp;
> + u64 tmp, uoff;
>
> offset -= flseg->pattern_offset;
> - tmp = offset;
> + tmp = uoff = offset;
> do_div(tmp, stripe_width);
>
> - return tmp * flseg->stripe_unit + do_div(offset, flseg->stripe_unit);
> + return tmp * flseg->stripe_unit + do_div(uoff, flseg->stripe_unit);
For proper u64 divisions it is best to use the div_u64 (and div64_u64) and not
use do_div. (And please don't add an unnecessary variable, just use a cast)
Thanks
Boaz
> }
>
> /* This function is used by the layout driver to calculate the
This change modifies filelayout_get_dense_offset() to use the functions
in math64.h and thus avoid a 32-bit platform compile error trying to
use do_div() on an s64 type.
Signed-off-by: Chris Metcalf <[email protected]>
Cc: Boaz Harrosh <[email protected]>
---
fs/nfs/nfs4filelayout.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index e8915d4..3ecb14f 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -49,12 +49,13 @@ filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg,
{
u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count;
u64 tmp;
+ u32 rem;
offset -= flseg->pattern_offset;
- tmp = offset;
- do_div(tmp, stripe_width);
+ tmp = div_u64(offset, stripe_width);
+ div_u64_rem(offset, flseg->stripe_unit, &rem);
- return tmp * flseg->stripe_unit + do_div(offset, flseg->stripe_unit);
+ return tmp * flseg->stripe_unit + rem;
}
/* This function is used by the layout driver to calculate the
--
1.6.5.2
On 8/10/2011 6:02 PM, Boaz Harrosh wrote:
> On 08/10/2011 10:56 AM, Chris Metcalf wrote:
>> Building on tilepro revealed two minor portability issues: the
>> blocklayout.c file used prefetchw() without #include <linux/prefetch.h>,
>> and the nfs4filelayout.c file used do_div() on an s64 not a u64.
>> This change fixes those two issues so the NFS code builds on tilepro.
>>
>> [...]
>> diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
>> index e8915d4..6976a72 100644
>> --- a/fs/nfs/nfs4filelayout.c
>> +++ b/fs/nfs/nfs4filelayout.c
>> @@ -48,13 +48,13 @@ filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg,
>> loff_t offset)
>> {
>> u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count;
>> - u64 tmp;
>> + u64 tmp, uoff;
>>
>> offset -= flseg->pattern_offset;
>> - tmp = offset;
>> + tmp = uoff = offset;
>> do_div(tmp, stripe_width);
>>
>> - return tmp * flseg->stripe_unit + do_div(offset, flseg->stripe_unit);
>> + return tmp * flseg->stripe_unit + do_div(uoff, flseg->stripe_unit);
> For proper u64 divisions it is best to use the div_u64 (and div64_u64) and not
> use do_div. (And please don't add an unnecessary variable, just use a cast)
You can't use a cast with do_div() or you get errors about non-lvalues.
And the context here is that we want the remainder, not the divided result,
so we'd need a temporary variable anyway if we were going to use a routine
from math64.h, presumably div_u64_rem(). But that's just an inline wrapper
around do_div() anyway, so it's no more efficient, and not obviously any
less "cluttered" in the source code here. The original code author (who
I'm adding belatedly to this email) may have a stronger opinion.
I'm not the author or maintainer of this code, I just want it to compile
without warning on 32-bit architectures :-)
--
Chris Metcalf, Tilera Corp.
http://www.tilera.com
On 08/11/2011 12:32 PM, Chris Metcalf wrote:
> This change modifies filelayout_get_dense_offset() to use the functions
> in math64.h and thus avoid a 32-bit platform compile error trying to
> use do_div() on an s64 type.
>
> Signed-off-by: Chris Metcalf <[email protected]>
> Cc: Boaz Harrosh <[email protected]>
Thanks
Reviewed-by: Boaz Harrosh <[email protected]>
Just if you don't mind a name change. tmp => stripe_no
while at it.
---
From: Chris Metcalf <[email protected]>
Subject: [PATCH v3] nfs: fix a minor do_div portability issue
This change modifies filelayout_get_dense_offset() to use the functions
in math64.h and thus avoid a 32-bit platform compile error trying to
use do_div() on an s64 type.
Signed-off-by: Chris Metcalf <[email protected]>
Reviewed-by: Boaz Harrosh <[email protected]>
---
fs/nfs/nfs4filelayout.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index e8915d4..3ecb14f 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -49,12 +49,13 @@ filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg,
{
u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count;
u64 stripe_no;
+ u32 rem;
offset -= flseg->pattern_offset;
- tmp = offset;
- do_div(tmp, stripe_width);
+ stripe_no = div_u64(offset, stripe_width);
+ div_u64_rem(offset, flseg->stripe_unit, &rem);
- return tmp * flseg->stripe_unit + do_div(offset, flseg->stripe_unit);
+ return stripe_no * flseg->stripe_unit + rem;
}
/* This function is used by the layout driver to calculate the
-- 1.6.5.2