nbd: Use new qio_channel_*_all() functions

Rather than open-coding our own read/write-all functions, we
can make use of the recently-added qio code.  It slightly
changes the error message in one of the iotests.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20170905191114.5959-4-eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>

2 files changed, 7 insertions, 79 deletions

diff --git a/nbd/common.c b/nbd/common.c
index e288d1b..59a5316 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -20,51 +20,6 @@
 #include "qapi/error.h"
 #include "nbd-internal.h"
 
-/* nbd_wr_syncv
- * The function may be called from coroutine or from non-coroutine context.
- * When called from non-coroutine context @ioc must be in blocking mode.
- */
-ssize_t nbd_rwv(QIOChannel *ioc, struct iovec *iov, size_t niov, size_t length,
-                bool do_read, Error **errp)
-{
-    ssize_t done = 0;
-    struct iovec *local_iov = g_new(struct iovec, niov);
-    struct iovec *local_iov_head = local_iov;
-    unsigned int nlocal_iov = niov;
-
-    nlocal_iov = iov_copy(local_iov, nlocal_iov, iov, niov, 0, length);
-
-    while (nlocal_iov > 0) {
-        ssize_t len;
-        if (do_read) {
-            len = qio_channel_readv(ioc, local_iov, nlocal_iov, errp);
-        } else {
-            len = qio_channel_writev(ioc, local_iov, nlocal_iov, errp);
-        }
-        if (len == QIO_CHANNEL_ERR_BLOCK) {
-            /* errp should not be set */
-            assert(qemu_in_coroutine());
-            qio_channel_yield(ioc, do_read ? G_IO_IN : G_IO_OUT);
-            continue;
-        }
-        if (len < 0) {
-            done = -EIO;
-            goto cleanup;
-        }
-
-        if (do_read && len == 0) {
-            break;
-        }
-
-        iov_discard_front(&local_iov, &nlocal_iov, len);
-        done += len;
-    }
-
- cleanup:
-    g_free(local_iov_head);
-    return done;
-}
-
 /* Discard length bytes from channel.  Return -errno on failure and 0 on
  * success */
 int nbd_drop(QIOChannel *ioc, size_t size, Error **errp)
diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h
index 03549e3..8a609a2 100644
--- a/nbd/nbd-internal.h
+++ b/nbd/nbd-internal.h
@@ -85,28 +85,14 @@
 static inline int nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
                                Error **errp)
 {
-    struct iovec iov = { .iov_base = buffer, .iov_len = size };
-    ssize_t ret;
-
-    /* Sockets are kept in blocking mode in the negotiation phase.  After
-     * that, a non-readable socket simply means that another thread stole
-     * our request/reply.  Synchronization is done with recv_coroutine, so
-     * that this is coroutine-safe.
-     */
+    int ret;
 
     assert(size);
-
-    ret = nbd_rwv(ioc, &iov, 1, size, true, errp);
-    if (ret <= 0) {
-        return ret;
-    }
-
-    if (ret != size) {
-        error_setg(errp, "End of file");
-        return -EINVAL;
+    ret = qio_channel_read_all_eof(ioc, buffer, size, errp);
+    if (ret < 0) {
+        ret = -EIO;
     }
-
-    return 1;
+    return ret;
 }
 
 /* nbd_read
@@ -115,14 +101,7 @@ static inline int nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
                            Error **errp)
 {
-    int ret = nbd_read_eof(ioc, buffer, size, errp);
-
-    if (ret == 0) {
-        ret = -EINVAL;
-        error_setg(errp, "End of file");
-    }
-
-    return ret < 0 ? ret : 0;
+    return qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
 }
 
 /* nbd_write
@@ -131,13 +110,7 @@ static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
 static inline int nbd_write(QIOChannel *ioc, const void *buffer, size_t size,
                             Error **errp)
 {
-    struct iovec iov = { .iov_base = (void *) buffer, .iov_len = size };
-
-    ssize_t ret = nbd_rwv(ioc, &iov, 1, size, false, errp);
-
-    assert(ret < 0 || ret == size);
-
-    return ret < 0 ? ret : 0;
+    return qio_channel_write_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
 }
 
 struct NBDTLSHandshakeData {