Commit 906e36c5 authored Oct 13, 2014 by Mike Travis Committed by Linus Torvalds Oct 14, 2014

x86: use optimized ioresource lookup in ioremap function



Use the optimized ioresource lookup, "region_is_ram", for the ioremap
function.  If the region is not found, it falls back to the
"page_is_ram" function.  If it is found and it is RAM, then the usual
warning message is issued, and the ioremap operation is aborted.
Otherwise, the ioremap operation continues.

Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Alex Thorlton <athorlton@sgi.com>
Reviewed-by: Cliff Wickman <cpw@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 67cf13ce

arch/x86/mm/ioremap.c

+16 −4

Original line number	Diff line number	Diff line
		@@ -86,6 +86,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
		pgprot_t prot;
		int retval;
		void __iomem *ret_addr;
		int ram_region;

		/* Don't allow wraparound or zero size */
		last_addr = phys_addr + size - 1;
		@@ -108,12 +109,23 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
		/*
		* Don't allow anybody to remap normal RAM that we're using..
		*/
		/* First check if whole region can be identified as RAM or not */
		ram_region = region_is_ram(phys_addr, size);
		if (ram_region > 0) {
		WARN_ONCE(1, "ioremap on RAM at 0x%lx - 0x%lx\n",
		(unsigned long int)phys_addr,
		(unsigned long int)last_addr);
		return NULL;
		}

		/* If could not be identified(-1), check page by page */
		if (ram_region < 0) {
		pfn = phys_addr >> PAGE_SHIFT;
		last_pfn = last_addr >> PAGE_SHIFT;
		if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
		__ioremap_check_ram) == 1)
		return NULL;

		}
		/*
		* Mappings have to be page-aligned
		*/