From cb6247a7e3e07ead908d2e7fbc8848cc2e135056 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 27 Mar 2013 17:36:28 +0100 Subject: [PATCH] iov: reorganize iov_send_recv, part 1 Once the initial part of the iov is dropped, it is not used anymore. Modify iov/iovcnt directly instead of adjusting them with the "si" variable. Reviewed-by: Juan Quintela Reviewed-by: Orit Wassermann Signed-off-by: Paolo Bonzini --- util/iov.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/util/iov.c b/util/iov.c index 9dae31819..adb9a70fc 100644 --- a/util/iov.c +++ b/util/iov.c @@ -159,16 +159,22 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, for (si = 0; si < iov_cnt && offset >= iov[si].iov_len; ++si) { offset -= iov[si].iov_len; } + + /* si == iov_cnt would only be valid if bytes == 0, which + * we already ruled out above. */ + assert(si < iov_cnt); + iov += si; + iov_cnt -= si; + if (offset) { - assert(si < iov_cnt); /* second, skip `offset' bytes from the (now) first element, * undo it on exit */ - iov[si].iov_base += offset; - iov[si].iov_len -= offset; + iov[0].iov_base += offset; + iov[0].iov_len -= offset; } /* Find the end position skipping `bytes' bytes: */ /* first, skip all full-sized elements */ - for (ei = si; ei < iov_cnt && iov[ei].iov_len <= bytes; ++ei) { + for (ei = 0; ei < iov_cnt && iov[ei].iov_len <= bytes; ++ei) { bytes -= iov[ei].iov_len; } if (bytes) { @@ -183,12 +189,12 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, ++ei; } - ret = do_send_recv(sockfd, iov + si, ei - si, do_send); + ret = do_send_recv(sockfd, iov, ei, do_send); /* Undo the changes above */ if (offset) { - iov[si].iov_base -= offset; - iov[si].iov_len += offset; + iov[0].iov_base -= offset; + iov[0].iov_len += offset; } if (bytes) { iov[ei-1].iov_len += bytes; -- 2.39.2