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authorAl Viro <viro@zeniv.linux.org.uk>2014-11-27 20:27:08 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2014-12-08 20:25:23 -0500
commitaa583096d9767892983332e7c1a984bd17e3cd39 (patch)
tree0a95463b6a62365ee6e37a8f2f4258ad7073197a
parentabb78f875f3fcedb88d85eef9f7be7aa474c6727 (diff)
copy_from_iter_nocache()
BTW, do we want memcpy_nocache()? Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--include/linux/uio.h1
-rw-r--r--mm/iov_iter.c21
2 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/uio.h b/include/linux/uio.h
index c567655b9595..bd8569a14c4a 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -83,6 +83,7 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);
size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i);
size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
+size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
size_t iov_iter_zero(size_t bytes, struct iov_iter *);
unsigned long iov_iter_alignment(const struct iov_iter *i);
void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 88c052e63a1d..a1599ca4ab0e 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -399,6 +399,27 @@ size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
}
EXPORT_SYMBOL(copy_from_iter);
+size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
+{
+ char *to = addr;
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ iterate_and_advance(i, bytes, v,
+ __copy_from_user_nocache((to += v.iov_len) - v.iov_len,
+ v.iov_base, v.iov_len),
+ memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
+ v.bv_offset, v.bv_len),
+ memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
+ )
+
+ return bytes;
+}
+EXPORT_SYMBOL(copy_from_iter_nocache);
+
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{