LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: haveblue@us.ibm.com, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, mbligh@google.com
Subject: Re: [PATCH] Cast page_to_pfn to unsigned long in CONFIG_SPARSEMEM
Date: Mon, 19 Nov 2007 13:08:01 -0800	[thread overview]
Message-ID: <20071119130801.bd7b7021.akpm@linux-foundation.org> (raw)
In-Reply-To: <20071119202023.GA5086@Krystal>

On Mon, 19 Nov 2007 15:20:23 -0500
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> wrote:

> * Dave Hansen (haveblue@us.ibm.com) wrote:
> > The only thing I might suggest doing differently is actually using the
> > page_to_pfn() definition itself:
> > 
> > memory_model.h:#define page_to_pfn __page_to_pfn
> > 
> > The full inline function version should do this already, and we
> > shouldn't have any real direct __page_to_pfn() users anyway.    
> > 
> 
> Like this then..
> 
> Cast page_to_pfn to unsigned long in CONFIG_SPARSEMEM
> 
> Make sure the type returned by page_to_pfn is always unsigned long. If we
> don't cast it explicitly, it can be int on i386, but long on x86_64.

formally ptrdiff_t, I believe.

> This is
> especially inelegant for printks.
> 
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> CC: Dave Hansen <haveblue@us.ibm.com>
> CC: linux-mm@kvack.org
> CC: linux-kernel@vger.kernel.org
> ---
>  include/asm-generic/memory_model.h |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux-2.6-lttng/include/asm-generic/memory_model.h
> ===================================================================
> --- linux-2.6-lttng.orig/include/asm-generic/memory_model.h	2007-11-19 15:06:40.000000000 -0500
> +++ linux-2.6-lttng/include/asm-generic/memory_model.h	2007-11-19 15:18:57.000000000 -0500
> @@ -76,7 +76,7 @@ struct page;
>  extern struct page *pfn_to_page(unsigned long pfn);
>  extern unsigned long page_to_pfn(struct page *page);
>  #else
> -#define page_to_pfn __page_to_pfn
> +#define page_to_pfn ((unsigned long)__page_to_pfn)
>  #define pfn_to_page __pfn_to_page
>  #endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */

I'd have thought that __pfn_to_page() was the place to fix this: the
lower-level point.  Because someone might later start using __pfn_to_page()
for something.

Heaven knows why though - why does __pfn_to_page() even exist?

  reply	other threads:[~2007-11-19 21:14 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-13 19:33 [RFC 0/7] LTTng Kernel Instrumentation (Architecture Independent) Mathieu Desnoyers
2007-11-13 19:33 ` [RFC 1/7] Include marker.h in kernel.h -- temporary, for code readability Mathieu Desnoyers
2007-11-13 19:33 ` [RFC 2/7] LTTng instrumentation fs Mathieu Desnoyers
2007-11-13 19:33 ` [RFC 3/7] LTTng instrumentation ipc Mathieu Desnoyers
2007-11-13 19:33 ` [RFC 4/7] LTTng instrumentation kernel Mathieu Desnoyers
2007-11-15 23:30   ` Mike Mason
2007-11-15 23:54     ` Mike Mason
2007-11-16  2:42       ` Mathieu Desnoyers
2007-11-16  2:22     ` Mathieu Desnoyers
2007-11-13 19:33 ` [RFC 5/7] LTTng instrumentation mm Mathieu Desnoyers
2007-11-15 21:06   ` Dave Hansen
2007-11-15 21:51     ` Mathieu Desnoyers
2007-11-15 22:16       ` Dave Hansen
2007-11-16 14:30         ` Mathieu Desnoyers
2007-11-19 18:04           ` Dave Hansen
2007-11-28 14:09             ` [RFC PATCH] LTTng instrumentation mm (using page_to_pfn) Mathieu Desnoyers
2007-11-28 16:54               ` Dave Hansen
2007-11-29  2:34                 ` Mathieu Desnoyers
2007-11-29  6:25                   ` Dave Hansen
2007-11-30 16:11                     ` [RFC PATCH] LTTng instrumentation mm (updated) Mathieu Desnoyers
2007-11-30 17:46                       ` Dave Hansen
2007-11-30 17:05                         ` Mathieu Desnoyers
2007-11-30 18:42                           ` Dave Hansen
2007-11-30 19:10                             ` Mathieu Desnoyers
2007-12-04 19:15                               ` Frank Ch. Eigler
2007-12-04 19:25                                 ` Mathieu Desnoyers
2007-12-04 19:40                                   ` Dave Hansen
2007-12-04 20:05                                     ` Mathieu Desnoyers
2007-12-04 20:24                                       ` Dave Hansen
2007-12-04 20:28                                       ` Dave Hansen
2007-11-16 14:47         ` [RFC 5/7] LTTng instrumentation mm Mathieu Desnoyers
2007-11-19 18:07           ` Dave Hansen
2007-11-19 18:52             ` Mathieu Desnoyers
2007-11-19 19:00               ` Mathieu Desnoyers
2007-11-19 19:43                 ` Dave Hansen
2007-11-19 19:43               ` Dave Hansen
2007-11-19 19:52                 ` [PATCH] Cast __page_to_pfn to unsigned long in CONFIG_SPARSEMEM Mathieu Desnoyers
2007-11-19 20:09                   ` Dave Hansen
2007-11-19 20:20                     ` [PATCH] Cast page_to_pfn " Mathieu Desnoyers
2007-11-19 21:08                       ` Andrew Morton [this message]
2007-11-19 21:19                         ` Dave Hansen
2007-11-19 21:26                           ` Dave Hansen
2007-11-21 20:12                           ` Christoph Lameter
2007-11-20 17:34                         ` Mathieu Desnoyers
2007-11-13 19:33 ` [RFC 6/7] LTTng instrumentation net Mathieu Desnoyers
2007-11-13 19:33 ` [RFC 7/7] Add Markers Into Semaphore Primitives Mathieu Desnoyers

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20071119130801.bd7b7021.akpm@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=haveblue@us.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mathieu.desnoyers@polymtl.ca \
    --cc=mbligh@google.com \
    --subject='Re: [PATCH] Cast page_to_pfn to unsigned long in CONFIG_SPARSEMEM' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).