cleanup qemu_co_sendv(), qemu_co_recvv() and friends

The same as for non-coroutine versions in previous
patches: rename arguments to be more obvious, change
type of arguments from int to size_t where appropriate,
and use common code for send and receive paths (with
one extra argument) since these are exactly the same.
Use common iov_send_recv() directly.

qemu_co_sendv(), qemu_co_recvv(), and qemu_co_recv()
are now trivial #define's merely adding one extra arg.

qemu_co_sendv() and qemu_co_recvv() callers are
converted to different argument order and extra
`iov_cnt' argument.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

block/nbd.c

@@ -196,7 +196,7 @@ static void nbd_restart_write(void *opaque)
 }
 
 static int nbd_co_send_request(BDRVNBDState *s, struct nbd_request *request,
-                               struct iovec *iov, int offset)
+                               QEMUIOVector *qiov, int offset)
 {
     int rc, ret;
 
@@ -205,8 +205,9 @@ static int nbd_co_send_request(BDRVNBDState *s, struct nbd_request *request,
     qemu_aio_set_fd_handler(s->sock, nbd_reply_ready, nbd_restart_write,
                             nbd_have_request, s);
     rc = nbd_send_request(s->sock, request);
-    if (rc >= 0 && iov) {
-        ret = qemu_co_sendv(s->sock, iov, request->len, offset);
+    if (rc >= 0 && qiov) {
+        ret = qemu_co_sendv(s->sock, qiov->iov, qiov->niov,
+                            offset, request->len);
         if (ret != request->len) {
             return -EIO;
         }
@@ -220,7 +221,7 @@ static int nbd_co_send_request(BDRVNBDState *s, struct nbd_request *request,
 
 static void nbd_co_receive_reply(BDRVNBDState *s, struct nbd_request *request,
                                  struct nbd_reply *reply,
-                                 struct iovec *iov, int offset)
+                                 QEMUIOVector *qiov, int offset)
 {
     int ret;
 
@@ -231,8 +232,9 @@ static void nbd_co_receive_reply(BDRVNBDState *s, struct nbd_request *request,
     if (reply->handle != request->handle) {
         reply->error = EIO;
     } else {
-        if (iov && reply->error == 0) {
-            ret = qemu_co_recvv(s->sock, iov, request->len, offset);
+        if (qiov && reply->error == 0) {
+            ret = qemu_co_recvv(s->sock, qiov->iov, qiov->niov,
+                                offset, request->len);
             if (ret != request->len) {
                 reply->error = EIO;
             }
@@ -349,7 +351,7 @@ static int nbd_co_readv_1(BlockDriverState *bs, int64_t sector_num,
     if (ret < 0) {
         reply.error = -ret;
     } else {
-        nbd_co_receive_reply(s, &request, &reply, qiov->iov, offset);
+        nbd_co_receive_reply(s, &request, &reply, qiov, offset);
     }
     nbd_coroutine_end(s, &request);
     return -reply.error;
@@ -374,7 +376,7 @@ static int nbd_co_writev_1(BlockDriverState *bs, int64_t sector_num,
     request.len = nb_sectors * 512;
 
     nbd_coroutine_start(s, &request);
-    ret = nbd_co_send_request(s, &request, qiov->iov, offset);
+    ret = nbd_co_send_request(s, &request, qiov, offset);
     if (ret < 0) {
         reply.error = -ret;
     } else {

block/sheepdog.c

@@ -719,8 +719,8 @@ static void coroutine_fn aio_read_response(void *opaque)
         }
         break;
     case AIOCB_READ_UDATA:
-        ret = qemu_co_recvv(fd, acb->qiov->iov, rsp.data_length,
-                            aio_req->iov_offset);
+        ret = qemu_co_recvv(fd, acb->qiov->iov, acb->qiov->niov,
+                            aio_req->iov_offset, rsp.data_length);
         if (ret < 0) {
             error_report("failed to get the data, %s", strerror(errno));
             goto out;
@@ -992,7 +992,7 @@ static int coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
     }
 
     if (wlen) {
-        ret = qemu_co_sendv(s->fd, iov, wlen, aio_req->iov_offset);
+        ret = qemu_co_sendv(s->fd, iov, niov, aio_req->iov_offset, wlen);
         if (ret < 0) {
             qemu_co_mutex_unlock(&s->lock);
             error_report("failed to send a data, %s", strerror(errno));

qemu-common.h

@@ -300,32 +300,29 @@ struct qemu_work_item {
 void qemu_init_vcpu(void *env);
 #endif
 
-/**
- * Sends an iovec (or optionally a part of it) down a socket, yielding
- * when the socket is full.
- */
-int qemu_co_sendv(int sockfd, struct iovec *iov,
-                  int len, int iov_offset);
 
 /**
- * Receives data into an iovec (or optionally into a part of it) from
- * a socket, yielding when there is no data in the socket.
+ * Sends a (part of) iovec down a socket, yielding when the socket is full, or
+ * Receives data into a (part of) iovec from a socket,
+ * yielding when there is no data in the socket.
+ * The same interface as qemu_sendv_recvv(), with added yielding.
+ * XXX should mark these as coroutine_fn
  */
-int qemu_co_recvv(int sockfd, struct iovec *iov,
-                  int len, int iov_offset);
-
+ssize_t qemu_co_sendv_recvv(int sockfd, struct iovec *iov, unsigned iov_cnt,
+                            size_t offset, size_t bytes, bool do_send);
+#define qemu_co_recvv(sockfd, iov, iov_cnt, offset, bytes) \
+  qemu_co_sendv_recvv(sockfd, iov, iov_cnt, offset, bytes, false)
+#define qemu_co_sendv(sockfd, iov, iov_cnt, offset, bytes) \
+  qemu_co_sendv_recvv(sockfd, iov, iov_cnt, offset, bytes, true)
 
 /**
- * Sends a buffer down a socket, yielding when the socket is full.
+ * The same as above, but with just a single buffer
  */
-int qemu_co_send(int sockfd, void *buf, int len);
-
-/**
- * Receives data into a buffer from a socket, yielding when there
- * is no data in the socket.
- */
-int qemu_co_recv(int sockfd, void *buf, int len);
-
+ssize_t qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send);
+#define qemu_co_recv(sockfd, buf, bytes) \
+  qemu_co_send_recv(sockfd, buf, bytes, false)
+#define qemu_co_send(sockfd, buf, bytes) \
+  qemu_co_send_recv(sockfd, buf, bytes, true)
 
 typedef struct QEMUIOVector {
     struct iovec *iov;

qemu-coroutine-io.c

@@ -27,71 +27,39 @@
 #include "qemu-coroutine.h"
 #include "iov.h"
 
-int coroutine_fn qemu_co_recvv(int sockfd, struct iovec *iov,
-                               int len, int iov_offset)
+ssize_t coroutine_fn
+qemu_co_sendv_recvv(int sockfd, struct iovec *iov, unsigned iov_cnt,
+                    size_t offset, size_t bytes, bool do_send)
 {
-    int total = 0;
-    int ret;
-    while (len) {
-        ret = iov_recv(sockfd, iov, iov_offset + total, len);
-        if (ret < 0) {
+    size_t done = 0;
+    ssize_t ret;
+    while (done < bytes) {
+        ret = iov_send_recv(sockfd, iov,
+                            offset + done, bytes - done, do_send);
+        if (ret > 0) {
+            done += ret;
+        } else if (ret < 0) {
             if (errno == EAGAIN) {
                 qemu_coroutine_yield();
-                continue;
-            }
-            if (total == 0) {
-                total = -1;
-            }
-            break;
-        }
-        if (ret == 0) {
-            break;
-        }
-        total += ret, len -= ret;
-    }
-
-    return total;
-}
-
-int coroutine_fn qemu_co_sendv(int sockfd, struct iovec *iov,
-                               int len, int iov_offset)
-{
-    int total = 0;
-    int ret;
-    while (len) {
-        ret = iov_send(sockfd, iov, iov_offset + total, len);
-        if (ret < 0) {
-            if (errno == EAGAIN) {
-                qemu_coroutine_yield();
-                continue;
-            }
-            if (total == 0) {
-                total = -1;
+            } else if (done == 0) {
+                return -1;
+            } else {
+                break;
             }
+        } else if (ret == 0 && !do_send) {
+            /* write (send) should never return 0.
+             * read (recv) returns 0 for end-of-file (-data).
+             * In both cases there's little point retrying,
+             * but we do for write anyway, just in case */
             break;
         }
-        total += ret, len -= ret;
     }
-
-    return total;
+    return done;
 }
 
-int coroutine_fn qemu_co_recv(int sockfd, void *buf, int len)
+ssize_t coroutine_fn
+qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send)
 {
-    struct iovec iov;
-
-    iov.iov_base = buf;
-    iov.iov_len = len;
-
-    return qemu_co_recvv(sockfd, &iov, len, 0);
-}
-
-int coroutine_fn qemu_co_send(int sockfd, void *buf, int len)
-{
-    struct iovec iov;
-
-    iov.iov_base = buf;
-    iov.iov_len = len;
-
-    return qemu_co_sendv(sockfd, &iov, len, 0);
+    struct iovec iov = { .iov_base = buf, .iov_len = bytes };
+    return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send);
 }