[PATCH] dax: constify second argument of dax_iomap_pmd_fault

[PATCH] dax: constify second argument of dax_iomap_pmd_fault

[Jérémy Lefaure]

When CONFIG_FS_DAX_PMD is disabled, the second argument of the function
dax_iomap_pmd_fault is not a const pointer. The compiler raises a
warning about that:
fs/dax.c: In function ‘dax_iomap_fault’:
fs/dax.c:1462:35: warning: passing argument 2 of ‘dax_iomap_pmd_fault’
discards ‘const’ qualifier from pointer target type
   return dax_iomap_pmd_fault(vmf, ops);
                                   ^~~
fs/dax.c:1439:12: note: expected ‘struct iomap_ops *’ but argument is of
type ‘const struct iomap_ops *’
static int dax_iomap_pmd_fault(struct vm_fault *vmf, struct iomap_ops *ops)
           ^~~~~~~~~~~~~~~~~~~

Constifying the second argument as it is when CONFIG_FX_DAX_PMD is
enabled fixes this warning.

Fixes: a2d581675d48("mm,fs,dax: change ->pmd_fault to ->huge_fault")
Signed-off-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>
---
 fs/dax.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/dax.c b/fs/dax.c
index 5ae8b71ebadc..7436c98b92c8 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1436,7 +1436,8 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,
 	return result;
 }
 #else
-static int dax_iomap_pmd_fault(struct vm_fault *vmf, struct iomap_ops *ops)
+static int dax_iomap_pmd_fault(struct vm_fault *vmf,
+			       const struct iomap_ops *ops)
 {
 	return VM_FAULT_FALLBACK;
 }
-- 
2.11.1

Re: [PATCH] dax: constify second argument of dax_iomap_pmd_fault

[Dave Jiang]

On 02/27/2017 05:20 PM, Jérémy Lefaure wrote:
> When CONFIG_FS_DAX_PMD is disabled, the second argument of the function
> dax_iomap_pmd_fault is not a const pointer. The compiler raises a
> warning about that:
> fs/dax.c: In function ‘dax_iomap_fault’:
> fs/dax.c:1462:35: warning: passing argument 2 of ‘dax_iomap_pmd_fault’
> discards ‘const’ qualifier from pointer target type
>    return dax_iomap_pmd_fault(vmf, ops);
>                                    ^~~
> fs/dax.c:1439:12: note: expected ‘struct iomap_ops *’ but argument is of
> type ‘const struct iomap_ops *’
> static int dax_iomap_pmd_fault(struct vm_fault *vmf, struct iomap_ops *ops)
>            ^~~~~~~~~~~~~~~~~~~
> 
> Constifying the second argument as it is when CONFIG_FX_DAX_PMD is
> enabled fixes this warning.
> 
> Fixes: a2d581675d48("mm,fs,dax: change ->pmd_fault to ->huge_fault")
> Signed-off-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>

Thanks. Fix already submitted.
http://marc.info/?l=linux-mm&m=148821429608976&w=2


> ---
>  fs/dax.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/dax.c b/fs/dax.c
> index 5ae8b71ebadc..7436c98b92c8 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1436,7 +1436,8 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,
>  	return result;
>  }
>  #else
> -static int dax_iomap_pmd_fault(struct vm_fault *vmf, struct iomap_ops *ops)
> +static int dax_iomap_pmd_fault(struct vm_fault *vmf,
> +			       const struct iomap_ops *ops)
>  {
>  	return VM_FAULT_FALLBACK;
>  }
>