From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
BTW, do we want memcpy_nocache()?
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
include/linux/uio.h | 1 +
mm/iov_iter.c | 21 +++++++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/include/linux/uio.h b/include/linux/uio.h
index c567655..bd8569a 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 7c04051..e0605c1 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)
{
--
2.1.3
--
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