OpenE2K/qemu-e2k
13
4
Fork 0
Code Issues 4 Pull Requests Projects 2 Releases Activity

iov: reorganize iov_send_recv, part 2

Browse Source 
Do not touch the "bytes" argument anymore.  Instead, remember the
original length of the last iovec if we touch it, and restore it
afterwards.

This requires undoing the changes in opposite order.  The previous
algorithm didn't care.

Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Orit Wassermann <owasserm@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2013-03-27 17:36:29 +01:00
parent cb6247a7e3
commit 5209d6753c
1 changed files with 14 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
util/iov.c
View File

@ -145,7 +145,9 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
bool do_send) bool do_send)
{ {
ssize_t ret; ssize_t ret;
size_t orig_len, tail;
unsigned si, ei; /* start and end indexes */ unsigned si, ei; /* start and end indexes */
if (bytes == 0) { if (bytes == 0) {
/* Catch the do-nothing case early, as otherwise we will pass an /* Catch the do-nothing case early, as otherwise we will pass an
* empty iovec to sendmsg/recvmsg(), and not all implementations * empty iovec to sendmsg/recvmsg(), and not all implementations
@ -174,31 +176,29 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
} }
/* Find the end position skipping `bytes' bytes: */ /* Find the end position skipping `bytes' bytes: */
/* first, skip all full-sized elements */ /* first, skip all full-sized elements */
for (ei = 0; ei < iov_cnt && iov[ei].iov_len <= bytes; ++ei) { tail = bytes;
bytes -= iov[ei].iov_len; for (ei = 0; ei < iov_cnt && iov[ei].iov_len <= tail; ++ei) {
tail -= iov[ei].iov_len;
} }
if (bytes) { if (tail) {
/* second, fixup the last element, and remember /* second, fixup the last element, and remember the original
* the length we've cut from the end of it in `bytes' */ * length */
size_t tail;
assert(ei < iov_cnt); assert(ei < iov_cnt);
assert(iov[ei].iov_len > bytes); assert(iov[ei].iov_len > tail);
tail = iov[ei].iov_len - bytes; orig_len = iov[ei].iov_len;
iov[ei].iov_len = bytes; iov[ei++].iov_len = tail;
bytes = tail; /* bytes is now equal to the tail size */
++ei;
} }
ret = do_send_recv(sockfd, iov, ei, do_send); ret = do_send_recv(sockfd, iov, ei, do_send);
/* Undo the changes above */ /* Undo the changes above */
if (tail) {
iov[ei-1].iov_len = orig_len;
}
if (offset) { if (offset) {
iov[0].iov_base -= offset; iov[0].iov_base -= offset;
iov[0].iov_len += offset; iov[0].iov_len += offset;
} }
if (bytes) {
iov[ei-1].iov_len += bytes;
}
return ret; return ret;
} }