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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>
This commit is contained in:
Al Viro 2014-04-04 19:23:46 -04:00
parent 6abd232274
commit 81055e584f
1 changed files with 8 additions and 0 deletions
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8
mm/iov_iter.c
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@ -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;