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authorLinus Torvalds <torvalds@linux-foundation.org>2009-07-01 11:46:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-07-01 11:46:30 -0700
commit5a475ce4692f668b2615ae4ea1365c7c2d93f1dd (patch)
tree0349690bce5fe2396a3788bb1a4084ffd87ee308 /mm/nommu.c
parentd960eea974f5e500c0dcb95a934239cc1f481cfd (diff)
parent1c6a307a54668eda556f499c94e75086aaf8f80f (diff)
downloadvexpress-lsk-5a475ce4692f668b2615ae4ea1365c7c2d93f1dd.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: sh: LCDC dcache flush for deferred io sh: Fix compiler error and include the definition of IS_ERR_VALUE sh: re-add LCDC fbdev support to the Migo-R defconfig sh: fix se7724 ceu names sh: ms7724se: Enable sh_eth in defconfig. arch/sh/boards/mach-se/7206/io.c: Remove unnecessary semicolons sh: ms7724se: Add sh_eth support nommu: provide follow_pfn(). sh: Kill off unused DEBUG_BOOTMEM symbol. perf_counter tools: add cpu_relax()/rmb() definitions for sh. sh64: Hook up page fault events for software perf counters. sh: Hook up page fault events for software perf counters. sh: make set_perf_counter_pending() static inline. clocksource: sh_tmu: Make undefined TCOR behaviour less undefined.
Diffstat (limited to 'mm/nommu.c')
-rw-r--r--mm/nommu.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/mm/nommu.c b/mm/nommu.c
index bf0cc762a7d..53cab10fece 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -238,6 +238,27 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
}
EXPORT_SYMBOL(get_user_pages);
+/**
+ * follow_pfn - look up PFN at a user virtual address
+ * @vma: memory mapping
+ * @address: user virtual address
+ * @pfn: location to store found PFN
+ *
+ * Only IO mappings and raw PFN mappings are allowed.
+ *
+ * Returns zero and the pfn at @pfn on success, -ve otherwise.
+ */
+int follow_pfn(struct vm_area_struct *vma, unsigned long address,
+ unsigned long *pfn)
+{
+ if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+ return -EINVAL;
+
+ *pfn = address >> PAGE_SHIFT;
+ return 0;
+}
+EXPORT_SYMBOL(follow_pfn);
+
DEFINE_RWLOCK(vmlist_lock);
struct vm_struct *vmlist;