From: Linus Torvalds Date: Mon, 22 Jan 2007 16:53:24 +0000 (-0800) Subject: Revert "[PATCH] Fix up mmap_kmem" X-Git-Tag: v2.6.20-rc6~62 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6d3154cc1143f62c3b80d9929caeaec6db8cb451;p=linux-2.6 Revert "[PATCH] Fix up mmap_kmem" This reverts commit 99a10a60ba9bedcf5d70ef81414d3e03816afa3f. As per Hugh Dickins: "Nadia Derbey has reported that mmap of /dev/kmem no longer works with the kernel virtual address as offset, and Franck has confirmed that his patch came from a misunderstanding of what an offset means to /dev/kmem - whereas his patch description seems to say that he was correcting the offset on a few plaforms, there was no such problem to correct, and his patch was in fact changing its API on all platforms." Suggested-by: Hugh Dickins Cc: Franck Bui-Huu Cc: Nadia Derbey Cc: Andi Kleen Cc: Arjan van de Ven Cc: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 4f1813e047..f5c160caf9 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -293,8 +293,8 @@ static int mmap_kmem(struct file * file, struct vm_area_struct * vma) { unsigned long pfn; - /* Turn a pfn offset into an absolute pfn */ - pfn = PFN_DOWN(virt_to_phys((void *)PAGE_OFFSET)) + vma->vm_pgoff; + /* Turn a kernel-virtual address into a physical page frame */ + pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; /* * RED-PEN: on some architectures there is more mapped memory