[Qemu-devel] [PATCHv2 4/7] change prototypes of qemu_sendv() and qemu_recvv()

[Michael Tokarev]

Rename arguments and use size_t for sizes instead of int

-qemu_sendv(int sockfd, struct iovec *iov, int len, int iov_offset)
+qemu_sendv(int sockfd, struct iovec *iov, size_t offset, size_t bytes)

The main motivation was to make it clear that length and offset are
in _bytes_, not in iov elements: it was very confusing before, because
all standard functions which deals with iovecs expects number of iovs,
not bytes, even the fact that struct iovec has iov_len and iov_ prefix
does not help.  With "bytes" and "offset", especially since they're
now size_t, it is much more explicit.

All callers of qemu_sendv() and qemu_recvv() and related, like
qemu_co_sendv() and qemu_co_recvv(), were checked to verify that
it is safe to use unsigned datatype instead of int.

While at it, clean up misleading comment near do_sendv_recvv().

Note that the order of arguments is changed to: offset and bytes
(len and iov_offset) are swapped with each other.  This is to make
them consistent with very similar functions from qemu_iovec family,
where offset always follows qiov, to mean the place in it to start
from.

Signed-off-by: Michael Tokarev <address@hidden>
---
 cutils.c            |   34 ++++++++++++----------------------
 qemu-common.h       |    4 ++--
 qemu-coroutine-io.c |    4 ++--
 3 files changed, 16 insertions(+), 26 deletions(-)

diff --git a/cutils.c b/cutils.c
index 04e51f7..b3b9cfb 100644
--- a/cutils.c
+++ b/cutils.c
@@ -417,38 +417,28 @@ int qemu_parse_fd(const char *param)
  *
  * This function send/recv data from/to the iovec buffer directly.
  * The first `offset' bytes in the iovec buffer are skipped and next
- * `len' bytes are used.
- *
- * For example,
- *
- *   do_sendv_recvv(sockfd, iov, len, offset, 1);
- *
- * is equal to
- *
- *   char *buf = malloc(size);
- *   iov_to_buf(iov, iovcnt, buf, offset, size);
- *   send(sockfd, buf, size, 0);
- *   free(buf);
+ * `bytes' bytes are used.
  */
-static int do_sendv_recvv(int sockfd, struct iovec *iov, int len, int offset,
+static int do_sendv_recvv(int sockfd, struct iovec *iov, size_t offset, size_t 
bytes,
                           int do_sendv)
 {
-    int ret, diff, iovlen;
+    int ret, iovlen;
+    size_t diff;
     struct iovec *last_iov;
 
     /* last_iov is inclusive, so count from one.  */
     iovlen = 1;
     last_iov = iov;
-    len += offset;
+    bytes += offset;
 
-    while (last_iov->iov_len < len) {
-        len -= last_iov->iov_len;
+    while (last_iov->iov_len < bytes) {
+        bytes -= last_iov->iov_len;
 
         last_iov++;
         iovlen++;
     }
 
-    diff = last_iov->iov_len - len;
+    diff = last_iov->iov_len - bytes;
     last_iov->iov_len -= diff;
 
     while (iov->iov_len <= offset) {
@@ -510,13 +500,13 @@ static int do_sendv_recvv(int sockfd, struct iovec *iov, 
int len, int offset,
     return ret;
 }
 
-int qemu_recvv(int sockfd, struct iovec *iov, int len, int iov_offset)
+int qemu_recvv(int sockfd, struct iovec *iov, size_t offset, size_t bytes)
 {
-    return do_sendv_recvv(sockfd, iov, len, iov_offset, 0);
+    return do_sendv_recvv(sockfd, iov, offset, bytes, 0);
 }
 
-int qemu_sendv(int sockfd, struct iovec *iov, int len, int iov_offset)
+int qemu_sendv(int sockfd, struct iovec *iov, size_t offset, size_t bytes)
 {
-    return do_sendv_recvv(sockfd, iov, len, iov_offset, 1);
+    return do_sendv_recvv(sockfd, iov, offset, bytes, 1);
 }
 
diff --git a/qemu-common.h b/qemu-common.h
index e8d1429..bb75dd3 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -199,8 +199,8 @@ int qemu_pipe(int pipefd[2]);
 #define qemu_recv(sockfd, buf, len, flags) recv(sockfd, buf, len, flags)
 #endif
 
-int qemu_recvv(int sockfd, struct iovec *iov, int len, int iov_offset);
-int qemu_sendv(int sockfd, struct iovec *iov, int len, int iov_offset);
+int qemu_recvv(int sockfd, struct iovec *iov, size_t offset, size_t bytes);
+int qemu_sendv(int sockfd, struct iovec *iov, size_t offset, size_t bytes);
 
 /* Error handling.  */
 
diff --git a/qemu-coroutine-io.c b/qemu-coroutine-io.c
index 40fd514..df8ff21 100644
--- a/qemu-coroutine-io.c
+++ b/qemu-coroutine-io.c
@@ -32,7 +32,7 @@ int coroutine_fn qemu_co_recvv(int sockfd, struct iovec *iov,
     int total = 0;
     int ret;
     while (len) {
-        ret = qemu_recvv(sockfd, iov, len, iov_offset + total);
+        ret = qemu_recvv(sockfd, iov, iov_offset + total, len);
         if (ret < 0) {
             if (errno == EAGAIN) {
                 qemu_coroutine_yield();
@@ -58,7 +58,7 @@ int coroutine_fn qemu_co_sendv(int sockfd, struct iovec *iov,
     int total = 0;
     int ret;
     while (len) {
-        ret = qemu_sendv(sockfd, iov, len, iov_offset + total);
+        ret = qemu_sendv(sockfd, iov, iov_offset + total, len);
         if (ret < 0) {
             if (errno == EAGAIN) {
                 qemu_coroutine_yield();
-- 
1.7.9.1