From 03beb07664d768db97bf454ae5c9581cd4737bb4 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Sun, 26 Mar 2006 01:36:57 -0800 Subject: [PATCH] Add API for flushing Anon pages Currently, get_user_pages() returns fully coherent pages to the kernel for anything other than anonymous pages. This is a problem for things like fuse and the SCSI generic ioctl SG_IO which can potentially wish to do DMA to anonymous pages passed in by users. The fix is to add a new memory management API: flush_anon_page() which is used in get_user_pages() to make anonymous pages coherent. Signed-off-by: James Bottomley Cc: Russell King Cc: "David S. Miller" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cachetlb.txt | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'Documentation/cachetlb.txt') diff --git a/Documentation/cachetlb.txt b/Documentation/cachetlb.txt index 4ae418889b8..1f312a9893d 100644 --- a/Documentation/cachetlb.txt +++ b/Documentation/cachetlb.txt @@ -362,6 +362,15 @@ maps this page at its virtual address. likely that you will need to flush the instruction cache for copy_to_user_page(). + void flush_anon_page(struct page *page, unsigned long vmaddr) + When the kernel needs to access the contents of an anonymous + page, it calls this function (currently only + get_user_pages()). Note: flush_dcache_page() deliberately + doesn't work for an anonymous page. The default + implementation is a nop (and should remain so for all coherent + architectures). For incoherent architectures, it should flush + the cache of the page at vmaddr in the current user process. + void flush_icache_range(unsigned long start, unsigned long end) When the kernel stores into addresses that it will execute out of (eg when loading modules), this function is called. -- cgit v1.2.3