This patch uses 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@xxxxxxx> Acked-by: Alex Thorlton <athorlton@xxxxxxx> Reviewed-by: Cliff Wickman <cpw@xxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> --- v2: slight rearrangement of code v3: added Cc: stable --- arch/x86/mm/ioremap.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) --- linux.orig/arch/x86/mm/ioremap.c +++ linux/arch/x86/mm/ioremap.c @@ -86,6 +86,7 @@ static void __iomem *__ioremap_caller(re 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(re /* * Don't allow anybody to remap normal RAM that we're using.. */ - 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) + /* 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 */ -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>