| From 8dad53a11f8d94dceb540a5f8f153484f42be84b Mon Sep 17 00:00:00 2001 |
| From: Christoph Hellwig <hch@lst.de> |
| Date: Fri, 23 Jul 2021 15:50:17 -0700 |
| Subject: mm: call flush_dcache_page() in memcpy_to_page() and memzero_page() |
| |
| From: Christoph Hellwig <hch@lst.de> |
| |
| commit 8dad53a11f8d94dceb540a5f8f153484f42be84b upstream. |
| |
| memcpy_to_page and memzero_page can write to arbitrary pages, which |
| could be in the page cache or in high memory, so call |
| flush_kernel_dcache_pages to flush the dcache. |
| |
| This is a problem when using these helpers on dcache challeneged |
| architectures. Right now there are just a few users, chances are no one |
| used the PC floppy driver, the aha1542 driver for an ISA SCSI HBA, and a |
| few advanced and optional btrfs and ext4 features on those platforms yet |
| since the conversion. |
| |
| Link: https://lkml.kernel.org/r/20210713055231.137602-2-hch@lst.de |
| Fixes: bb90d4bc7b6a ("mm/highmem: Lift memcpy_[to|from]_page to core") |
| Fixes: 28961998f858 ("iov_iter: lift memzero_page() to highmem.h") |
| Signed-off-by: Christoph Hellwig <hch@lst.de> |
| Reviewed-by: Ira Weiny <ira.weiny@intel.com> |
| Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> |
| Cc: <stable@vger.kernel.org> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| include/linux/highmem.h | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| --- a/include/linux/highmem.h |
| +++ b/include/linux/highmem.h |
| @@ -329,6 +329,7 @@ static inline void memcpy_to_page(struct |
| |
| VM_BUG_ON(offset + len > PAGE_SIZE); |
| memcpy(to + offset, from, len); |
| + flush_dcache_page(page); |
| kunmap_local(to); |
| } |
| |
| @@ -336,6 +337,7 @@ static inline void memzero_page(struct p |
| { |
| char *addr = kmap_atomic(page); |
| memset(addr + offset, 0, len); |
| + flush_dcache_page(page); |
| kunmap_atomic(addr); |
| } |
| |
