From 877b58ebc038f5e3f0afc5674fc35db75eaaa117 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Mon, 30 Oct 2017 14:48:29 -0400 Subject: mtd: mtdram: properly handle the phys argument in the point method When the phys pointer is non null, the point method is expected to return the physical address for the pointed area. In the case of the mtdram driver we have to retrieve the physical address for the corresponding vmalloc area. However, there is no guarantee that the vmalloc area is made of physically contiguous pages. In that case we simply limit retlen to the actually contiguous pages. Signed-off-by: Nicolas Pitre Reviewed-by: Richard Weinberger Acked-by: Boris Brezillon Signed-off-by: Richard Weinberger --- drivers/mtd/devices/mtdram.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'drivers/mtd/devices') diff --git a/drivers/mtd/devices/mtdram.c b/drivers/mtd/devices/mtdram.c index cbd8547d7aad..4418629e8dc0 100644 --- a/drivers/mtd/devices/mtdram.c +++ b/drivers/mtd/devices/mtdram.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -69,6 +70,27 @@ static int ram_point(struct mtd_info *mtd, loff_t from, size_t len, { *virt = mtd->priv + from; *retlen = len; + + if (phys) { + /* limit retlen to the number of contiguous physical pages */ + unsigned long page_ofs = offset_in_page(*virt); + void *addr = *virt - page_ofs; + unsigned long pfn1, pfn0 = vmalloc_to_pfn(addr); + + *phys = __pfn_to_phys(pfn0) + page_ofs; + len += page_ofs; + while (len > PAGE_SIZE) { + len -= PAGE_SIZE; + addr += PAGE_SIZE; + pfn0++; + pfn1 = vmalloc_to_pfn(addr); + if (pfn1 != pfn0) { + *retlen = addr - *virt; + break; + } + } + } + return 0; } -- cgit v1.2.3