diff options
| author | James Bottomley <James.Bottomley@SteelEye.com> | 2006-03-26 01:36:59 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-26 08:56:53 -0800 |
| commit | 5a3a5a98b6422d05c39eaa32c8b3f83840c7b768 (patch) | |
| tree | e96a8f5543c94c57eb2b761fa94df9f7a9412e52 | |
| parent | 03beb07664d768db97bf454ae5c9581cd4737bb4 (diff) | |
[PATCH] Add flush_kernel_dcache_page() API
We have a problem in a lot of emulated storage in that it takes a page from
get_user_pages() and does something like
kmap_atomic(page)
modify page
kunmap_atomic(page)
However, nothing has flushed the kernel cache view of the page before the
kunmap. We need a lightweight API to do this, so this new API would
specifically be for flushing the kernel cache view of a user page which the
kernel has modified. The driver would need to add
flush_kernel_dcache_page(page) before the final kunmap.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | Documentation/cachetlb.txt | 12 | ||||
| -rw-r--r-- | include/linux/highmem.h | 6 |
2 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/cachetlb.txt b/Documentation/cachetlb.txt index 1f312a9893d..53245c429f7 100644 --- a/Documentation/cachetlb.txt +++ b/Documentation/cachetlb.txt @@ -371,6 +371,18 @@ maps this page at its virtual address. architectures). For incoherent architectures, it should flush the cache of the page at vmaddr in the current user process. + void flush_kernel_dcache_page(struct page *page) + When the kernel needs to modify a user page is has obtained + with kmap, it calls this function after all modifications are + complete (but before kunmapping it) to bring the underlying + page up to date. It is assumed here that the user has no + incoherent cached copies (i.e. the original page was obtained + from a mechanism like get_user_pages()). The default + implementation is a nop and should remain so on all coherent + architectures. On incoherent architectures, this should flush + the kernel cache for page (using page_address(page)). + + 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. diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 7bd2593dbef..892c4ea1b42 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -13,6 +13,12 @@ static inline void flush_anon_page(struct page *page, unsigned long vmaddr) } #endif +#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE +static inline void flush_kernel_dcache_page(struct page *page) +{ +} +#endif + #ifdef CONFIG_HIGHMEM #include <asm/highmem.h> |