diff options
| author | Ben Hutchings <ben@decadent.org.uk> | 2012-07-31 16:45:02 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-01-03 03:32:57 +0000 |
| commit | fcb8996728fb59eddf84678df7cb213b2c9a2e26 (patch) | |
| tree | 24e4c053d05194db2235cf872a5ef950e888c93b | |
| parent | 26e5f795726ed11feff7125d727377a3eb231403 (diff) | |
mm: add kmap_to_page()
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>
| -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 3a93f73a8ac..52e96204b3e 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -38,10 +38,17 @@ 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 57d82c6250c..d517cd16a6e 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; |