The patch titled
mm: introduce follow_pfn()
has been added to the -mm tree. Its filename is
mm-introduce-follow_pfn.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mm: introduce follow_pfn()
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Analoguous to follow_phys(), add a helper that looks up the PFN at a
user virtual address in an IO mapping or a raw PFN mapping.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Magnus Damm <magnus.damm@xxxxxxxxx>
Cc: Hans Verkuil <hverkuil@xxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 2 ++
mm/memory.c | 29 +++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff -puN include/linux/mm.h~mm-introduce-follow_pfn include/linux/mm.h
--- a/include/linux/mm.h~mm-introduce-follow_pfn
+++ a/include/linux/mm.h
@@ -817,6 +817,8 @@ int copy_page_range(struct mm_struct *ds
struct vm_area_struct *vma);
void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen, int even_cows);
+int follow_pfn(struct vm_area_struct *vma, unsigned long address,
+ unsigned long *pfn);
int follow_phys(struct vm_area_struct *vma, unsigned long address,
unsigned int flags, unsigned long *prot, resource_size_t *phys);
int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
diff -puN mm/memory.c~mm-introduce-follow_pfn mm/memory.c
--- a/mm/memory.c~mm-introduce-follow_pfn
+++ a/mm/memory.c
@@ -3228,6 +3228,35 @@ out:
return -EINVAL;
}
+/**
+ * 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)
+{
+ int ret = -EINVAL;
+ spinlock_t *ptl;
+ pte_t *ptep;
+
+ if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+ return ret;
+
+ ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
+ if (ret)
+ return ret;
+ *pfn = pte_pfn(*ptep);
+ pte_unmap_unlock(ptep, ptl);
+ return 0;
+}
+EXPORT_SYMBOL(follow_pfn);
+
#ifdef CONFIG_HAVE_IOREMAP_PROT
int follow_phys(struct vm_area_struct *vma,
unsigned long address, unsigned int flags,
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
origin.patch
linux-next.patch
eliminate-thousands-of-warnings-with-gcc-32-build.patch
eliminate-thousands-of-warnings-with-gcc-32-build-cleanup.patch
mm-page-writebackc-dirty-limit-type-should-be-unsigned-long.patch
vmscan-evict-use-once-pages-first-v3.patch
mm-introduce-follow_pte.patch
mm-use-generic-follow_pte-in-follow_phys.patch
mm-introduce-follow_pfn.patch
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