projects/linux·commit 03beb076

[PATCH] Add API for flushing Anon pages

03beb076 · James Bottomley <[email protected]> · 2006-03-26 01:36:57 -08:00

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 <[email protected]>
Cc: Russell King <[email protected]>
Cc: "David S. Miller" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Commit
03beb07664d768db97bf454ae5c9581cd4737bb4
Parents
64a07bd8

Changes

3 files changed · +17 −0

FileStatusAddDelContent
Documentation/cachetlb.txtmodified+9−0View file
include/linux/highmem.hmodified+6−0View file
mm/memory.cmodified+2−0View file

Documentation/cachetlb.txt

View file
diff --git a/Documentation/cachetlb.txt b/Documentation/cachetlb.txt
index 4ae4188..1f312a9 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.

include/linux/highmem.h

View file
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 6bece92..7bd2593 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -7,6 +7,12 @@
#include <asm/cacheflush.h>
+#ifndef ARCH_HAS_FLUSH_ANON_PAGE
+static inline void flush_anon_page(struct page *page, unsigned long vmaddr)
+{
+}
+#endif
+
#ifdef CONFIG_HIGHMEM
#include <asm/highmem.h>

mm/memory.c

View file
diff --git a/mm/memory.c b/mm/memory.c
index e347e10..6768604 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1071,6 +1071,8 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
}
if (pages) {
pages[i] = page;
+
+ flush_anon_page(page, start);
flush_dcache_page(page);
}
if (vmas)