From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pb-smtp1.pobox.com ([64.147.108.70] helo=sasl.smtp.pobox.com) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1e27fZ-0002Ln-0G for linux-mtd@lists.infradead.org; Wed, 11 Oct 2017 03:26:56 +0000 From: Nicolas Pitre To: Boris Brezillon Cc: linux-mtd@lists.infradead.org Subject: [PATCH 1/5] MTD: mtdram: properly handle the phys argument in the point method Date: Tue, 10 Oct 2017 23:26:17 -0400 Message-Id: <20171011032621.26979-2-nicolas.pitre@linaro.org> In-Reply-To: <20171011032621.26979-1-nicolas.pitre@linaro.org> References: <20171011032621.26979-1-nicolas.pitre@linaro.org> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 --- drivers/mtd/devices/mtdram.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/mtd/devices/mtdram.c b/drivers/mtd/devices/mtdram.c index cbd8547d7a..7dbee8e62f 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 = *virt - addr; + break; + } + } + } + return 0; } -- 2.9.5