2009-07-05 02:48:49

by Figo.zhang

Subject: [PATCH]mempool.c : clean up type-casting twice

clean up type-casting twice

Signed-off-by: Figo.zhang <[email protected]>
---
mm/mempool.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/mempool.c b/mm/mempool.c
index a46eb1b..0aec628 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -303,7 +303,7 @@ EXPORT_SYMBOL(mempool_free_slab);
*/
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
{
- size_t size = (size_t)(long)pool_data;
+ size_t size = (size_t)pool_data;
return kmalloc(size, gfp_mask);
}
EXPORT_SYMBOL(mempool_kmalloc);
@@ -327,14 +327,14 @@ EXPORT_SYMBOL(mempool_kfree);
*/
void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data)
{
- int order = (int)(long)pool_data;
+ int order = (int)pool_data;
return alloc_pages(gfp_mask, order);
}
EXPORT_SYMBOL(mempool_alloc_pages);

void mempool_free_pages(void *element, void *pool_data)
{
- int order = (int)(long)pool_data;
+ int order = (int)pool_data;
__free_pages(element, order);
}
EXPORT_SYMBOL(mempool_free_pages);

2009-07-05 03:01:16

by Ingo Molnar

Subject: Re: [PATCH]mempool.c : clean up type-casting twice

* Figo.zhang <[email protected]> wrote:

> clean up type-casting twice
>
> Signed-off-by: Figo.zhang <[email protected]>
> ---
> mm/mempool.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/mm/mempool.c b/mm/mempool.c
> index a46eb1b..0aec628 100644
> --- a/mm/mempool.c
> +++ b/mm/mempool.c
> @@ -303,7 +303,7 @@ EXPORT_SYMBOL(mempool_free_slab);
> */
> void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
> {
> - size_t size = (size_t)(long)pool_data;
> + size_t size = (size_t)pool_data;
> return kmalloc(size, gfp_mask);
> }
> EXPORT_SYMBOL(mempool_kmalloc);
> @@ -327,14 +327,14 @@ EXPORT_SYMBOL(mempool_kfree);
> */
> void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data)
> {
> - int order = (int)(long)pool_data;
> + int order = (int)pool_data;
> return alloc_pages(gfp_mask, order);
> }
> EXPORT_SYMBOL(mempool_alloc_pages);
>
> void mempool_free_pages(void *element, void *pool_data)
> {
> - int order = (int)(long)pool_data;
> + int order = (int)pool_data;
> __free_pages(element, order);

What's the motivation?

On 64-bit platforms, casting from a pointer (64-bit) straight to int
(32-bit) can lose information and is thus a potential source of
bugs, so certain compilers will warn about it with:

warning: cast from pointer to integer of different size

The double cast is a "I know what I'm doing" signal.

Ingo

2009-07-05 03:12:11

by Figo.zhang

Subject: Re: [PATCH]mempool.c : clean up type-casting twice

On Sun, 2009-07-05 at 05:01 +0200, Ingo Molnar wrote:
> * Figo.zhang <[email protected]> wrote:
>
> > clean up type-casting twice
> >
> > Signed-off-by: Figo.zhang <[email protected]>
> > ---
> > mm/mempool.c | 6 +++---
> > 1 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/mm/mempool.c b/mm/mempool.c
> > index a46eb1b..0aec628 100644
> > --- a/mm/mempool.c
> > +++ b/mm/mempool.c
> > @@ -303,7 +303,7 @@ EXPORT_SYMBOL(mempool_free_slab);
> > */
> > void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
> > {
> > - size_t size = (size_t)(long)pool_data;
> > + size_t size = (size_t)pool_data;
> > return kmalloc(size, gfp_mask);
> > }
> > EXPORT_SYMBOL(mempool_kmalloc);
> > @@ -327,14 +327,14 @@ EXPORT_SYMBOL(mempool_kfree);
> > */
> > void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data)
> > {
> > - int order = (int)(long)pool_data;
> > + int order = (int)pool_data;
> > return alloc_pages(gfp_mask, order);
> > }
> > EXPORT_SYMBOL(mempool_alloc_pages);
> >
> > void mempool_free_pages(void *element, void *pool_data)
> > {
> > - int order = (int)(long)pool_data;
> > + int order = (int)pool_data;
> > __free_pages(element, order);
>
> What's the motivation?
>
> On 64-bit platforms, casting from a pointer (64-bit) straight to int
> (32-bit) can lose information and is thus a potential source of
> bugs, so certain compilers will warn about it with:
>
> warning: cast from pointer to integer of different size
>
> The double cast is a "I know what I'm doing" signal.
>

thanks.


void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
{
size_t size = (size_t)(long)pool_data;
return kmalloc(size, gfp_mask);
}

void *mempool_kzalloc(gfp_t gfp_mask, void *pool_data)
{
size_t size = (size_t) pool_data;
return kzalloc(size, gfp_mask);
}

at this point, is it no need for type-casting twice ? because size_t is
typedef "unsigned int" in x86_32, "unsigned long " in x86_64.

Best,
Figo.zhang

2009-07-05 04:04:20

by Figo.zhang

Subject: [PATCH v2]mempool.c : clean up type-casting twice

clean up type-casting twice. "size_t" typedef as "unsigned long" in 64-bit system,
and "unsigned int" in 32-bit system.

Signed-off-by: Figo.zhang <[email protected]>
---
mm/mempool.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/mempool.c b/mm/mempool.c
index a46eb1b..bd22982 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -303,7 +303,7 @@ EXPORT_SYMBOL(mempool_free_slab);
*/
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
{
- size_t size = (size_t)(long)pool_data;
+ size_t size = (size_t) pool_data;
return kmalloc(size, gfp_mask);
}
EXPORT_SYMBOL(mempool_kmalloc);

2009-07-05 08:49:03

by Ingo Molnar

Subject: Re: [PATCH v2]mempool.c : clean up type-casting twice

* Figo.zhang <[email protected]> wrote:

> clean up type-casting twice. "size_t" typedef as "unsigned long" in 64-bit system,
> and "unsigned int" in 32-bit system.
>
> Signed-off-by: Figo.zhang <[email protected]>
> ---
> mm/mempool.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/mm/mempool.c b/mm/mempool.c
> index a46eb1b..bd22982 100644
> --- a/mm/mempool.c
> +++ b/mm/mempool.c
> @@ -303,7 +303,7 @@ EXPORT_SYMBOL(mempool_free_slab);
> */
> void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
> {
> - size_t size = (size_t)(long)pool_data;
> + size_t size = (size_t) pool_data;
> return kmalloc(size, gfp_mask);
> }
> EXPORT_SYMBOL(mempool_kmalloc);

(Style detail: please dont add spaces to casts. That should be fixed
in mempool_kzalloc() too btw.)

Looks good otherwise - size_t ought to be long on all 64-bit
architectures.

Ingo

2009-07-05 09:01:33

by Figo.zhang

Subject: [PATCH v3]mempool.c : clean up type-casting twice

clean up type-casting twice. "size_t" typedef as "unsigned long" in 64-bit system,
and "unsigned int" in 32-bit system.

in v3, remove the space to casts.

Signed-off-by: Figo.zhang <[email protected]>
---
mm/mempool.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/mempool.c b/mm/mempool.c
index a46eb1b..32e75d4 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -303,14 +303,14 @@ EXPORT_SYMBOL(mempool_free_slab);
*/
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
{
- size_t size = (size_t)(long)pool_data;
+ size_t size = (size_t)pool_data;
return kmalloc(size, gfp_mask);
}
EXPORT_SYMBOL(mempool_kmalloc);

void *mempool_kzalloc(gfp_t gfp_mask, void *pool_data)
{
- size_t size = (size_t) pool_data;
+ size_t size = (size_t)pool_data;
return kzalloc(size, gfp_mask);
}
EXPORT_SYMBOL(mempool_kzalloc);

2009-07-05 09:04:51

by Ingo Molnar

Subject: Re: [PATCH v3]mempool.c : clean up type-casting twice

* Figo.zhang <[email protected]> wrote:

> clean up type-casting twice. "size_t" typedef as "unsigned long" in 64-bit system,
> and "unsigned int" in 32-bit system.

[
You should line-length limit your changelogs btw., to 60
characters or so. git log will add another 4 characters. The
~/.vimrc magic for this is:

autocmd BufNewFile,BufRead *.patch setlocal textwidth=60
]

>
> in v3, remove the space to casts.
>
> Signed-off-by: Figo.zhang <[email protected]>
> ---
> mm/mempool.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mempool.c b/mm/mempool.c
> index a46eb1b..32e75d4 100644
> --- a/mm/mempool.c
> +++ b/mm/mempool.c
> @@ -303,14 +303,14 @@ EXPORT_SYMBOL(mempool_free_slab);
> */
> void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
> {
> - size_t size = (size_t)(long)pool_data;
> + size_t size = (size_t)pool_data;
> return kmalloc(size, gfp_mask);
> }
> EXPORT_SYMBOL(mempool_kmalloc);
>
> void *mempool_kzalloc(gfp_t gfp_mask, void *pool_data)
> {
> - size_t size = (size_t) pool_data;
> + size_t size = (size_t)pool_data;
> return kzalloc(size, gfp_mask);
> }
> EXPORT_SYMBOL(mempool_kzalloc);

Acked-by: Ingo Molnar <[email protected]>

Ingo

2009-07-05 09:13:45

by Figo.zhang

Subject: Re: [PATCH v3]mempool.c : clean up type-casting twice

On Sun, 2009-07-05 at 11:04 +0200, Ingo Molnar wrote:
> * Figo.zhang <[email protected]> wrote:
>
> > clean up type-casting twice. "size_t" typedef as "unsigned long" in 64-bit system,
> > and "unsigned int" in 32-bit system.
>
> [
> You should line-length limit your changelogs btw., to 60
> characters or so. git log will add another 4 characters. The
> ~/.vimrc magic for this is:
>
> autocmd BufNewFile,BufRead *.patch setlocal textwidth=60
> ]

hi,Ingo,

Thanks a lot.

should i motify the log, and send it again?

Best,
Figo.zhang


>
> >
> > in v3, remove the space to casts.
> >
> > Signed-off-by: Figo.zhang <[email protected]>
> > ---
> > mm/mempool.c | 4 ++--
> > 1 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/mm/mempool.c b/mm/mempool.c
> > index a46eb1b..32e75d4 100644
> > --- a/mm/mempool.c
> > +++ b/mm/mempool.c
> > @@ -303,14 +303,14 @@ EXPORT_SYMBOL(mempool_free_slab);
> > */
> > void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
> > {
> > - size_t size = (size_t)(long)pool_data;
> > + size_t size = (size_t)pool_data;
> > return kmalloc(size, gfp_mask);
> > }
> > EXPORT_SYMBOL(mempool_kmalloc);
> >
> > void *mempool_kzalloc(gfp_t gfp_mask, void *pool_data)
> > {
> > - size_t size = (size_t) pool_data;
> > + size_t size = (size_t)pool_data;
> > return kzalloc(size, gfp_mask);
> > }
> > EXPORT_SYMBOL(mempool_kzalloc);
>
> Acked-by: Ingo Molnar <[email protected]>
>
> Ingo

2009-07-05 09:20:32

by Figo.zhang

Subject: [PATCH v4]mempool.c : clean up type-casting twice

clean up type-casting twice. "size_t" typedef as "unsigned
long" in 64-bit system, and "unsigned int" in 32-bit system.

in v3, remove the space to casts.

in v4, change the line-length limit for git log.

Signed-off-by: Figo.zhang <[email protected]>
---

mm/mempool.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/mempool.c b/mm/mempool.c
index a46eb1b..32e75d4 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -303,14 +303,14 @@ EXPORT_SYMBOL(mempool_free_slab);
*/
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
{
- size_t size = (size_t)(long)pool_data;
+ size_t size = (size_t)pool_data;
return kmalloc(size, gfp_mask);
}
EXPORT_SYMBOL(mempool_kmalloc);

void *mempool_kzalloc(gfp_t gfp_mask, void *pool_data)
{
- size_t size = (size_t) pool_data;
+ size_t size = (size_t)pool_data;
return kzalloc(size, gfp_mask);
}
EXPORT_SYMBOL(mempool_kzalloc);