From 81055e584f9d743cb13dc7944923d817c20f089d Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 4 Apr 2014 19:23:46 -0400
Subject: [PATCH] optimize copy_page_{to,from}_iter()
if we'd ended up in the end of a segment, jump to the
beginning of the next one (iov_offset = 0, iov++),
rather than having the next primitive deal with that.
Ought to be folded back...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
mm/iov_iter.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 081e3273085bb6..fcdaaab438b677 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -74,6 +74,10 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
}
kunmap(page);
done:
+ if (skip == iov->iov_len) {
+ iov++;
+ skip = 0;
+ }
i->count -= wanted - bytes;
i->nr_segs -= iov - i->iov;
i->iov = iov;
@@ -152,6 +156,10 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
}
kunmap(page);
done:
+ if (skip == iov->iov_len) {
+ iov++;
+ skip = 0;
+ }
i->count -= wanted - bytes;
i->nr_segs -= iov - i->iov;
i->iov = iov;
--
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