From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Date: Tue, 08 Dec 2009 00:33:54 +0000 Subject: Re: [PATCH] mm/vmalloc: don't use vmalloc_end Message-Id: <4B1D9EF2.4010406@kernel.org> List-Id: References: <4B1D3A3302000078000241CD@vpn.id2.novell.com> <20091207153552.0fadf335.akpm@linux-foundation.org> In-Reply-To: <20091207153552.0fadf335.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: Jan Beulich , linux-kernel@vger.kernel.org, tony.luck@intel.com, linux-mm@kvack.org, linux-ia64@vger.kernel.org, Geert Uytterhoeven On 12/08/2009 08:35 AM, Andrew Morton wrote: > (cc linux-ia64) > > On Mon, 07 Dec 2009 16:24:03 +0000 > "Jan Beulich" wrote: > >> At least on ia64 vmalloc_end is a global variable that VMALLOC_END >> expands to. Hence having a local variable named vmalloc_end and >> initialized from VMALLOC_END won't work on such platforms. Rename >> these variables, and for consistency also rename vmalloc_start. >> > > erk. So does 2.6.32's vmalloc() actually work correctly on ia64? > > Perhaps vmalloc_end wasn't a well chosen name for an arch-specific > global variable. > > arch/m68k/include/asm/pgtable_mm.h does the same thing. Did it break too? Hmmm... ISTR writing a patch updating ia64 so that it doesn't use that macro. Looking it up.... Yeap, 126b3fcdecd350cad9700908d0ad845084e26a31 in percpu#for-next. ia64: don't alias VMALLOC_END to vmalloc_end If CONFIG_VIRTUAL_MEM_MAP is enabled, ia64 defines macro VMALLOC_END as unsigned long variable vmalloc_end which is adjusted to prepare room for vmemmap. This becomes probnlematic if a local variables vmalloc_end is defined in some function (not very unlikely) and VMALLOC_END is used in the function - the function thinks its referencing the global VMALLOC_END value but would be referencing its own local vmalloc_end variable. There's no reason VMALLOC_END should be a macro. Just define it as an unsigned long variable if CONFIG_VIRTUAL_MEM_MAP is set to avoid nasty surprises. Signed-off-by: Tejun Heo Acked-by: Tony Luck Cc: Fenghua Yu Cc: linux-ia64 Cc: Christoph Lameter 2.6.32 doesn't use new allocator on ia64 yet and the above commit will be sent to Linus soon which will also enable new allocator. Thanks. -- tejun