Re: [Xen-devel] [PATCH v2 5/8] xen/tmem: Use page_to_gfn rather than pfn_to_gfn

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 4 Aug 2015, Julien Grall wrote:
> All the caller of xen_tmem_{get,put}_page have a struct page * in hand
> and call pfn_to_gfn for the only benefits of these 2 functions.
> 
> Rather than passing the pfn in parameter, pass directly the page and use
> directly page_to_gfn.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: David Vrabel <david.vrabel@xxxxxxxxxx>

Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>


>  drivers/xen/tmem.c | 21 +++++++--------------
>  1 file changed, 7 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
> index 28c97ff..e0c8dc7 100644
> --- a/drivers/xen/tmem.c
> +++ b/drivers/xen/tmem.c
> @@ -129,21 +129,17 @@ static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
>  /* xen generic tmem ops */
>  
>  static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
> -                          u32 index, unsigned long pfn)
> +                          u32 index, struct page *page)
>  {
> -     unsigned long gmfn = pfn_to_gfn(pfn);
> -
>       return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
> -             gmfn, 0, 0, 0);
> +                        page_to_gfn(page), 0, 0, 0);
>  }
>  
>  static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
> -                          u32 index, unsigned long pfn)
> +                          u32 index, struct page *page)
>  {
> -     unsigned long gmfn = pfn_to_gfn(pfn);
> -
>       return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
> -             gmfn, 0, 0, 0);
> +                        page_to_gfn(page), 0, 0, 0);
>  }
>  
>  static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
> @@ -173,14 +169,13 @@ static void tmem_cleancache_put_page(int pool, struct 
> cleancache_filekey key,
>  {
>       u32 ind = (u32) index;
>       struct tmem_oid oid = *(struct tmem_oid *)&key;
> -     unsigned long pfn = page_to_pfn(page);
>  
>       if (pool < 0)
>               return;
>       if (ind != index)
>               return;
>       mb(); /* ensure page is quiescent; tmem may address it with an alias */
> -     (void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
> +     (void)xen_tmem_put_page((u32)pool, oid, ind, page);
>  }
>  
>  static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
> @@ -287,7 +282,6 @@ static int tmem_frontswap_store(unsigned type, pgoff_t 
> offset,
>  {
>       u64 ind64 = (u64)offset;
>       u32 ind = (u32)offset;
> -     unsigned long pfn = page_to_pfn(page);
>       int pool = tmem_frontswap_poolid;
>       int ret;
>  
> @@ -296,7 +290,7 @@ static int tmem_frontswap_store(unsigned type, pgoff_t 
> offset,
>       if (ind64 != ind)
>               return -1;
>       mb(); /* ensure page is quiescent; tmem may address it with an alias */
> -     ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
> +     ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), page);
>       /* translate Xen tmem return values to linux semantics */
>       if (ret == 1)
>               return 0;
> @@ -313,7 +307,6 @@ static int tmem_frontswap_load(unsigned type, pgoff_t 
> offset,
>  {
>       u64 ind64 = (u64)offset;
>       u32 ind = (u32)offset;
> -     unsigned long pfn = page_to_pfn(page);
>       int pool = tmem_frontswap_poolid;
>       int ret;
>  
> @@ -321,7 +314,7 @@ static int tmem_frontswap_load(unsigned type, pgoff_t 
> offset,
>               return -1;
>       if (ind64 != ind)
>               return -1;
> -     ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
> +     ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), page);
>       /* translate Xen tmem return values to linux semantics */
>       if (ret == 1)
>               return 0;
> -- 
> 2.1.4
> 

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