From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, mbligh@google.com
Subject: [PATCH] Cast __page_to_pfn to unsigned long in CONFIG_SPARSEMEM
Date: Mon, 19 Nov 2007 14:52:58 -0500 [thread overview]
Message-ID: <20071119195257.GA3440@Krystal> (raw)
In-Reply-To: <1195501381.27759.127.camel@localhost>
* Dave Hansen (haveblue@us.ibm.com) wrote:
> On Mon, 2007-11-19 at 13:52 -0500, Mathieu Desnoyers wrote:
> > > > So I guess the result is a pointer ? Should this be expected ?
> > >
> > > Nope. 'pointer - pointer' is an integer. Just solve this equation for
> > > integer:
> > >
> > > 'pointer + integer = pointer'
> > >
> >
> > Well, using page_to_pfn turns out to be ugly in markers (and in
> > printks) then. Depending on the architecture, it will result in either
> > an unsigned long (x86_64) or an unsigned int (i386), which corresponds
> > to %lu or %u and will print a warning if we don't cast it explicitly.
>
> Casting the i386 one to be an unconditional 'unsigned long' shouldn't be
> an issue. We don't generally expect pfns to fit into ints anyway.
So would this make sense ?
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. 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 14:47:30.000000000 -0500
+++ linux-2.6-lttng/include/asm-generic/memory_model.h 2007-11-19 14:48:30.000000000 -0500
@@ -50,7 +50,7 @@
/* memmap is virtually contigious. */
#define __pfn_to_page(pfn) (vmemmap + (pfn))
-#define __page_to_pfn(page) ((page) - vmemmap)
+#define __page_to_pfn(page) ((unsigned long)((page) - vmemmap))
#elif defined(CONFIG_SPARSEMEM)
/*
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
next prev parent reply other threads:[~2007-11-19 19:58 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 ` Mathieu Desnoyers [this message]
2007-11-19 20:09 ` [PATCH] Cast __page_to_pfn to unsigned long in CONFIG_SPARSEMEM Dave Hansen
2007-11-19 20:20 ` [PATCH] Cast page_to_pfn " Mathieu Desnoyers
2007-11-19 21:08 ` Andrew Morton
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
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