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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 02/10] iov_iter: Renumber the ITER_* constants in uio.h From: David Howells To: viro@zeniv.linux.org.uk Cc: dhowells@redhat.com, linux-afs@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, matthew@wil.cx Date: Mon, 06 Aug 2018 14:16:52 +0100 Message-ID: <153356141193.1195.857800682411976761.stgit@warthog.procyon.org.uk> In-Reply-To: <153356139813.1195.8360582774280288285.stgit@warthog.procyon.org.uk> References: <153356139813.1195.8360582774280288285.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Mon, 06 Aug 2018 13:16:53 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Mon, 06 Aug 2018 13:16:53 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'dhowells@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Renumber the ITER_* constants in uio.h to be contiguous to make comparing them more efficient in a switch-statement. Signed-off-by: David Howells --- include/linux/uio.h | 8 +++--- lib/iov_iter.c | 69 +++++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 60 insertions(+), 17 deletions(-) diff --git a/include/linux/uio.h b/include/linux/uio.h index 48e7fa36f923..d5f8755bf778 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -22,10 +22,10 @@ struct kvec { }; enum iter_type { - ITER_IOVEC = 0, - ITER_KVEC = 2, - ITER_BVEC = 4, - ITER_PIPE = 8, + ITER_IOVEC, + ITER_KVEC, + ITER_BVEC, + ITER_PIPE, }; struct iov_iter { diff --git a/lib/iov_iter.c b/lib/iov_iter.c index bd828591afb0..f30ecd263d6e 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -75,18 +75,28 @@ #define iterate_all_kinds(i, n, v, I, B, K) { \ if (likely(n)) { \ size_t skip = i->iov_offset; \ - if (unlikely(i->iter_type & ITER_BVEC)) { \ + switch (iov_iter_type(i)) { \ + case ITER_BVEC: { \ struct bio_vec v; \ struct bvec_iter __bi; \ - iterate_bvec(i, n, v, __bi, skip, (B)) \ - } else if (unlikely(i->iter_type & ITER_KVEC)) { \ + iterate_bvec(i, n, v, __bi, skip, (B)); \ + break; \ + } \ + case ITER_KVEC: { \ const struct kvec *kvec; \ struct kvec v; \ - iterate_kvec(i, n, v, kvec, skip, (K)) \ - } else { \ + iterate_kvec(i, n, v, kvec, skip, (K)); \ + break; \ + } \ + case ITER_PIPE: { \ + break; \ + } \ + case ITER_IOVEC: { \ const struct iovec *iov; \ struct iovec v; \ - iterate_iovec(i, n, v, iov, skip, (I)) \ + iterate_iovec(i, n, v, iov, skip, (I)); \ + break; \ + } \ } \ } \ } @@ -96,7 +106,8 @@ n = i->count; \ if (i->count) { \ size_t skip = i->iov_offset; \ - if (unlikely(i->iter_type & ITER_BVEC)) { \ + switch (iov_iter_type(i)) { \ + case ITER_BVEC: { \ const struct bio_vec *bvec = i->bvec; \ struct bio_vec v; \ struct bvec_iter __bi; \ @@ -104,7 +115,9 @@ i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ i->nr_segs -= i->bvec - bvec; \ skip = __bi.bi_bvec_done; \ - } else if (unlikely(i->iter_type & ITER_KVEC)) { \ + break; \ + } \ + case ITER_KVEC: { \ const struct kvec *kvec; \ struct kvec v; \ iterate_kvec(i, n, v, kvec, skip, (K)) \ @@ -114,7 +127,9 @@ } \ i->nr_segs -= kvec - i->kvec; \ i->kvec = kvec; \ - } else { \ + break; \ + } \ + case ITER_IOVEC: { \ const struct iovec *iov; \ struct iovec v; \ iterate_iovec(i, n, v, iov, skip, (I)) \ @@ -124,6 +139,11 @@ } \ i->nr_segs -= iov - i->iov; \ i->iov = iov; \ + break; \ + } \ + case ITER_PIPE: { \ + break; \ + } \ } \ i->count -= n; \ i->iov_offset = skip; \ @@ -873,6 +893,7 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, case ITER_IOVEC: return copy_page_from_iter_iovec(page, offset, bytes, i); } + WARN_ON(1); return 0; } @@ -988,11 +1009,17 @@ static void pipe_advance(struct iov_iter *i, size_t size) void iov_iter_advance(struct iov_iter *i, size_t size) { - if (unlikely(iov_iter_is_pipe(i))) { + switch (iov_iter_type(i)) { + case ITER_PIPE: pipe_advance(i, size); return; + case ITER_IOVEC: + case ITER_KVEC: + case ITER_BVEC: + iterate_and_advance(i, size, v, 0, 0, 0); + return; } - iterate_and_advance(i, size, v, 0, 0, 0) + BUG(); } EXPORT_SYMBOL(iov_iter_advance); @@ -1223,8 +1250,16 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, if (maxsize > i->count) maxsize = i->count; - if (unlikely(iov_iter_is_pipe(i))) + switch (iov_iter_type(i)) { + case ITER_PIPE: return pipe_get_pages(i, pages, maxsize, maxpages, start); + case ITER_KVEC: + return -EFAULT; + case ITER_IOVEC: + case ITER_BVEC: + break; + } + iterate_all_kinds(i, maxsize, v, ({ unsigned long addr = (unsigned long)v.iov_base; size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); @@ -1300,8 +1335,16 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, if (maxsize > i->count) maxsize = i->count; - if (unlikely(iov_iter_is_pipe(i))) + switch (iov_iter_type(i)) { + case ITER_PIPE: return pipe_get_pages_alloc(i, pages, maxsize, start); + case ITER_KVEC: + return -EFAULT; + case ITER_IOVEC: + case ITER_BVEC: + break; + } + iterate_all_kinds(i, maxsize, v, ({ unsigned long addr = (unsigned long)v.iov_base; size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));