From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id B7D0B6B004D for ; Fri, 27 Nov 2009 03:22:06 -0500 (EST) Received: by ywh3 with SMTP id 3so1201496ywh.22 for ; Fri, 27 Nov 2009 00:22:00 -0800 (PST) From: Magnus Damm Date: Fri, 27 Nov 2009 17:16:34 +0900 Message-Id: <20091127081634.29712.67793.sendpatchset@rxone.opensource.se> Subject: [PATCH][RESEND] mm: uncached vma support with writenotify Sender: owner-linux-mm@kvack.org To: linux-mm@kvack.org Cc: Magnus Damm , lethal@linux-sh.org, jayakumar.lkml@gmail.com, akpm@linux-foundation.org, arnd@arndb.de List-ID: From: Magnus Damm This patch modifies the generic mmap() code to keep the cache attribute in vma->vm_page_prot regardless if writenotify is enabled or not. Without this patch the cache configuration selected by f_op->mmap() is overwritten if writenotify is enabled, making it impossible to keep the vma uncached. Needed by drivers such as drivers/video/sh_mobile_lcdcfb.c which uses deferred io together with uncached memory. Signed-off-by: Magnus Damm --- Identical to the patch sent 20090614. It's been a while since then, is it now safe to use pgprot_noncached() without #ifdefs? mm/mmap.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) --- 0001/mm/mmap.c +++ work/mm/mmap.c 2009-11-27 16:44:40.000000000 +0900 @@ -1220,8 +1220,20 @@ munmap_back: goto free_vma; } - if (vma_wants_writenotify(vma)) + if (vma_wants_writenotify(vma)) { + pgprot_t pprot = vma->vm_page_prot; + + /* Can vma->vm_page_prot have changed?? + * + * Answer: Yes, drivers may have changed it in their + * f_op->mmap method. + * + * Ensures that vmas marked as uncached stay that way. + */ vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); + if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + } vma_link(mm, vma, prev, rb_link, rb_parent); file = vma->vm_file; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org