From f0f6b614f83dbae99d283b7b12ab5dd2e04df979 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 23 Jun 2022 17:21:37 -0400 Subject: [PATCH] copy_page_to_iter(): don't split high-order page in case of ITER_PIPE ... just shove it into one pipe_buffer. Signed-off-by: Al Viro --- lib/iov_iter.c | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 46ec078..4e3696d 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -706,30 +706,21 @@ static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) return false; } -static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, - struct iov_iter *i) -{ - if (unlikely(iov_iter_is_pipe(i))) { - return copy_page_to_iter_pipe(page, offset, bytes, i); - } else { - void *kaddr = kmap_local_page(page); - size_t wanted = _copy_to_iter(kaddr + offset, bytes, i); - kunmap_local(kaddr); - return wanted; - } -} - size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { size_t res = 0; if (unlikely(!page_copy_sane(page, offset, bytes))) return 0; + if (unlikely(iov_iter_is_pipe(i))) + return copy_page_to_iter_pipe(page, offset, bytes, i); page += offset / PAGE_SIZE; // first subpage offset %= PAGE_SIZE; while (1) { - size_t n = __copy_page_to_iter(page, offset, - min(bytes, (size_t)PAGE_SIZE - offset), i); + void *kaddr = kmap_local_page(page); + size_t n = min(bytes, (size_t)PAGE_SIZE - offset); + n = _copy_to_iter(kaddr + offset, n, i); + kunmap_local(kaddr); res += n; bytes -= n; if (!bytes || !n) -- 2.7.4