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commit dbc2fba3fc46084f502aec53183995a632998dcd
parent 5f739e4a491ab63730ef3b7464171340c689fbff
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 12 Mar 2019 13:43:42 -0700

Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull iov_iter updates from Al Viro:
 "A couple of iov_iter patches - Christoph's crapectomy (the last
  remaining user of iov_for_each() went away with lustre, IIRC) and
  Eric'c optimization of sanity checks"

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  iov_iter: optimize page_copy_sane()
  uio: remove the unused iov_for_each macro

Diffstat:
M.clang-format | 1-
Minclude/linux/uio.h | 8--------
Mlib/iov_iter.c | 17+++++++++++++++--
3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/.clang-format b/.clang-format @@ -290,7 +290,6 @@ ForEachMacros: - 'idr_for_each_entry_ul' - 'inet_bind_bucket_for_each' - 'inet_lhash2_for_each_icsk_rcu' - - 'iov_for_each' - 'key_for_each' - 'key_for_each_safe' - 'klp_for_each_func' diff --git a/include/linux/uio.h b/include/linux/uio.h @@ -110,14 +110,6 @@ static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) }; } -#define iov_for_each(iov, iter, start) \ - if (iov_iter_type(start) == ITER_IOVEC || \ - iov_iter_type(start) == ITER_KVEC) \ - for (iter = (start); \ - (iter).count && \ - ((iov = iov_iter_iovec(&(iter))), 1); \ - iov_iter_advance(&(iter), (iov).iov_len)) - size_t iov_iter_copy_from_user_atomic(struct page *page, struct iov_iter *i, unsigned long offset, size_t bytes); void iov_iter_advance(struct iov_iter *i, size_t bytes); diff --git a/lib/iov_iter.c b/lib/iov_iter.c @@ -861,8 +861,21 @@ EXPORT_SYMBOL(_copy_from_iter_full_nocache); static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) { - struct page *head = compound_head(page); - size_t v = n + offset + page_address(page) - page_address(head); + struct page *head; + size_t v = n + offset; + + /* + * The general case needs to access the page order in order + * to compute the page size. + * However, we mostly deal with order-0 pages and thus can + * avoid a possible cache line miss for requests that fit all + * page orders. + */ + if (n <= v && v <= PAGE_SIZE) + return true; + + head = compound_head(page); + v += (page - head) << PAGE_SHIFT; if (likely(n <= v && v <= (PAGE_SIZE << compound_order(head)))) return true;