diff options
| author | Ben Hutchings <ben@decadent.org.uk> | 2012-07-31 16:45:02 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-06-11 12:04:17 -0700 |
| commit | 7e4d02fdb2bb0f47405a0961a7f3991a56b5981b (patch) | |
| tree | 5daed7ed40bcc14e59a6ec0e19d88fcd087ffd19 | |
| parent | 984ca88a55ccf51d4eeef67ce2247c58694a2dc5 (diff) | |
mm: add kmap_to_page()
commit fcb8996728fb59eddf84678df7cb213b2c9a2e26 upstream.
This is extracted from Mel Gorman's commit 5a178119b0fb ('mm: add
support for direct_IO to highmem pages') upstream.
Required to backport commit b9cdc88df8e6 ('virtio: 9p: correctly pass
physical address to userspace for high pages').
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/highmem.h | 7 | ||||
| -rw-r--r-- | mm/highmem.c | 12 |
2 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h index d3999b4e26cc..e186e3c28ed8 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -39,10 +39,17 @@ extern unsigned long totalhigh_pages; void kmap_flush_unused(void); +struct page *kmap_to_page(void *addr); + #else /* CONFIG_HIGHMEM */ static inline unsigned int nr_free_highpages(void) { return 0; } +static inline struct page *kmap_to_page(void *addr) +{ + return virt_to_page(addr); +} + #define totalhigh_pages 0UL #ifndef ARCH_HAS_KMAP diff --git a/mm/highmem.c b/mm/highmem.c index 57d82c6250c3..d517cd16a6eb 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -94,6 +94,18 @@ static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait); do { spin_unlock(&kmap_lock); (void)(flags); } while (0) #endif +struct page *kmap_to_page(void *vaddr) +{ + unsigned long addr = (unsigned long)vaddr; + + if (addr >= PKMAP_ADDR(0) && addr <= PKMAP_ADDR(LAST_PKMAP)) { + int i = (addr - PKMAP_ADDR(0)) >> PAGE_SHIFT; + return pte_page(pkmap_page_table[i]); + } + + return virt_to_page(addr); +} + static void flush_all_zero_pkmaps(void) { int i; |