[Qemu-devel] [PATCH 01/19] nbd/server: get rid of nbd_negotiate_read and friends

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Functions nbd_negotiate_{read,write,drop_sync} were introduced in
1a6245a5b, when nbd_wr_syncv was working through qemu_co_sendv_recvv,
which just yields, without setting any handlers. But now, nbd_wr_syncv
works through qio_channel_yield() which sets handlers, so watchers
are redundant in nbd_negotiate_{read,write,drop_sync}, then, let's just
use {read,write,drop}_sync functions.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 nbd/client.c       |  26 -------------
 nbd/common.c       |  26 +++++++++++++
 nbd/nbd-internal.h |   2 +
 nbd/server.c       | 107 +++++++++++------------------------------------------
 4 files changed, 50 insertions(+), 111 deletions(-)

diff --git a/nbd/client.c b/nbd/client.c
index f9e1d75be4..3d15596120 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -86,32 +86,6 @@ static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
 
 */
 
-/* Discard length bytes from channel.  Return -errno on failure and 0 on
- * success*/
-static int drop_sync(QIOChannel *ioc, size_t size, Error **errp)
-{
-    ssize_t ret = 0;
-    char small[1024];
-    char *buffer;
-
-    buffer = sizeof(small) >= size ? small : g_malloc(MIN(65536, size));
-    while (size > 0) {
-        ssize_t count = MIN(65536, size);
-        ret = read_sync(ioc, buffer, MIN(65536, size), errp);
-
-        if (ret < 0) {
-            goto cleanup;
-        }
-        size -= count;
-    }
-
- cleanup:
-    if (buffer != small) {
-        g_free(buffer);
-    }
-    return ret;
-}
-
 /* Send an option request.
  *
  * The request is for option @opt, with @data containing @len bytes of
diff --git a/nbd/common.c b/nbd/common.c
index bd81637ab9..e520aae741 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -69,6 +69,32 @@ ssize_t nbd_wr_syncv(QIOChannel *ioc,
     return done;
 }
 
+/* Discard length bytes from channel.  Return -errno on failure and 0 on
+ * success*/
+int drop_sync(QIOChannel *ioc, size_t size, Error **errp)
+{
+    ssize_t ret = 0;
+    char small[1024];
+    char *buffer;
+
+    buffer = sizeof(small) >= size ? small : g_malloc(MIN(65536, size));
+    while (size > 0) {
+        ssize_t count = MIN(65536, size);
+        ret = read_sync(ioc, buffer, MIN(65536, size), errp);
+
+        if (ret < 0) {
+            goto cleanup;
+        }
+        size -= count;
+    }
+
+ cleanup:
+    if (buffer != small) {
+        g_free(buffer);
+    }
+    return ret;
+}
+
 
 void nbd_tls_handshake(QIOTask *task,
                        void *opaque)
diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h
index d6071640a0..01d5778679 100644
--- a/nbd/nbd-internal.h
+++ b/nbd/nbd-internal.h
@@ -153,4 +153,6 @@ struct NBDTLSHandshakeData {
 void nbd_tls_handshake(QIOTask *task,
                        void *opaque);
 
+int drop_sync(QIOChannel *ioc, size_t size, Error **errp);
+
 #endif
diff --git a/nbd/server.c b/nbd/server.c
index ee59e5d234..26096f14e1 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -104,69 +104,6 @@ struct NBDClient {
 
 static void nbd_client_receive_next_request(NBDClient *client);
 
-static gboolean nbd_negotiate_continue(QIOChannel *ioc,
-                                       GIOCondition condition,
-                                       void *opaque)
-{
-    qemu_coroutine_enter(opaque);
-    return TRUE;
-}
-
-static int nbd_negotiate_read(QIOChannel *ioc, void *buffer, size_t size)
-{
-    ssize_t ret;
-    guint watch;
-
-    assert(qemu_in_coroutine());
-    /* Negotiation are always in main loop. */
-    watch = qio_channel_add_watch(ioc,
-                                  G_IO_IN,
-                                  nbd_negotiate_continue,
-                                  qemu_coroutine_self(),
-                                  NULL);
-    ret = read_sync(ioc, buffer, size, NULL);
-    g_source_remove(watch);
-    return ret;
-
-}
-
-static int nbd_negotiate_write(QIOChannel *ioc, const void *buffer, size_t size)
-{
-    ssize_t ret;
-    guint watch;
-
-    assert(qemu_in_coroutine());
-    /* Negotiation are always in main loop. */
-    watch = qio_channel_add_watch(ioc,
-                                  G_IO_OUT,
-                                  nbd_negotiate_continue,
-                                  qemu_coroutine_self(),
-                                  NULL);
-    ret = write_sync(ioc, buffer, size, NULL);
-    g_source_remove(watch);
-    return ret;
-}
-
-static int nbd_negotiate_drop_sync(QIOChannel *ioc, size_t size)
-{
-    ssize_t ret;
-    uint8_t *buffer = g_malloc(MIN(65536, size));
-
-    while (size > 0) {
-        size_t count = MIN(65536, size);
-        ret = nbd_negotiate_read(ioc, buffer, count);
-        if (ret < 0) {
-            g_free(buffer);
-            return ret;
-        }
-
-        size -= count;
-    }
-
-    g_free(buffer);
-    return 0;
-}
-
 /* Basic flow for negotiation
 
    Server         Client
@@ -205,22 +142,22 @@ static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
           type, opt, len);
 
     magic = cpu_to_be64(NBD_REP_MAGIC);
-    if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) < 0) {
+    if (write_sync(ioc, &magic, sizeof(magic), NULL) < 0) {
         LOG("write failed (rep magic)");
         return -EINVAL;
     }
     opt = cpu_to_be32(opt);
-    if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) < 0) {
+    if (write_sync(ioc, &opt, sizeof(opt), NULL) < 0) {
         LOG("write failed (rep opt)");
         return -EINVAL;
     }
     type = cpu_to_be32(type);
-    if (nbd_negotiate_write(ioc, &type, sizeof(type)) < 0) {
+    if (write_sync(ioc, &type, sizeof(type), NULL) < 0) {
         LOG("write failed (rep type)");
         return -EINVAL;
     }
     len = cpu_to_be32(len);
-    if (nbd_negotiate_write(ioc, &len, sizeof(len)) < 0) {
+    if (write_sync(ioc, &len, sizeof(len), NULL) < 0) {
         LOG("write failed (rep data length)");
         return -EINVAL;
     }
@@ -255,7 +192,7 @@ nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type,
     if (ret < 0) {
         goto out;
     }
-    if (nbd_negotiate_write(ioc, msg, len) < 0) {
+    if (write_sync(ioc, msg, len, NULL) < 0) {
         LOG("write failed (error message)");
         ret = -EIO;
     } else {
@@ -286,15 +223,15 @@ static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
     }
 
     len = cpu_to_be32(name_len);
-    if (nbd_negotiate_write(ioc, &len, sizeof(len)) < 0) {
+    if (write_sync(ioc, &len, sizeof(len), NULL) < 0) {
         LOG("write failed (name length)");
         return -EINVAL;
     }
-    if (nbd_negotiate_write(ioc, name, name_len) < 0) {
+    if (write_sync(ioc, name, name_len, NULL) < 0) {
         LOG("write failed (name buffer)");
         return -EINVAL;
     }
-    if (nbd_negotiate_write(ioc, desc, desc_len) < 0) {
+    if (write_sync(ioc, desc, desc_len, NULL) < 0) {
         LOG("write failed (description buffer)");
         return -EINVAL;
     }
@@ -308,7 +245,7 @@ static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length)
     NBDExport *exp;
 
     if (length) {
-        if (nbd_negotiate_drop_sync(client->ioc, length) < 0) {
+        if (drop_sync(client->ioc, length, NULL) < 0) {
             return -EIO;
         }
         return nbd_negotiate_send_rep_err(client->ioc,
@@ -339,7 +276,7 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length)
         LOG("Bad length received");
         goto fail;
     }
-    if (nbd_negotiate_read(client->ioc, name, length) < 0) {
+    if (read_sync(client->ioc, name, length, NULL) < 0) {
         LOG("read failed");
         goto fail;
     }
@@ -372,7 +309,7 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
     TRACE("Setting up TLS");
     ioc = client->ioc;
     if (length) {
-        if (nbd_negotiate_drop_sync(ioc, length) < 0) {
+        if (drop_sync(ioc, length, NULL) < 0) {
             return NULL;
         }
         nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS,
@@ -436,7 +373,7 @@ static int nbd_negotiate_options(NBDClient *client)
         ...           Rest of request
     */
 
-    if (nbd_negotiate_read(client->ioc, &flags, sizeof(flags)) < 0) {
+    if (read_sync(client->ioc, &flags, sizeof(flags), NULL) < 0) {
         LOG("read failed");
         return -EIO;
     }
@@ -462,7 +399,7 @@ static int nbd_negotiate_options(NBDClient *client)
         uint32_t clientflags, length;
         uint64_t magic;
 
-        if (nbd_negotiate_read(client->ioc, &magic, sizeof(magic)) < 0) {
+        if (read_sync(client->ioc, &magic, sizeof(magic), NULL) < 0) {
             LOG("read failed");
             return -EINVAL;
         }
@@ -472,15 +409,15 @@ static int nbd_negotiate_options(NBDClient *client)
             return -EINVAL;
         }
 
-        if (nbd_negotiate_read(client->ioc, &clientflags,
-                               sizeof(clientflags)) < 0)
+        if (read_sync(client->ioc, &clientflags,
+                      sizeof(clientflags), NULL) < 0)
         {
             LOG("read failed");
             return -EINVAL;
         }
         clientflags = be32_to_cpu(clientflags);
 
-        if (nbd_negotiate_read(client->ioc, &length, sizeof(length)) < 0) {
+        if (read_sync(client->ioc, &length, sizeof(length), NULL) < 0) {
             LOG("read failed");
             return -EINVAL;
         }
@@ -510,7 +447,7 @@ static int nbd_negotiate_options(NBDClient *client)
                 return -EINVAL;
 
             default:
-                if (nbd_negotiate_drop_sync(client->ioc, length) < 0) {
+                if (drop_sync(client->ioc, length, NULL) < 0) {
                     return -EIO;
                 }
                 ret = nbd_negotiate_send_rep_err(client->ioc,
@@ -548,7 +485,7 @@ static int nbd_negotiate_options(NBDClient *client)
                 return nbd_negotiate_handle_export_name(client, length);
 
             case NBD_OPT_STARTTLS:
-                if (nbd_negotiate_drop_sync(client->ioc, length) < 0) {
+                if (drop_sync(client->ioc, length, NULL) < 0) {
                     return -EIO;
                 }
                 if (client->tlscreds) {
@@ -567,7 +504,7 @@ static int nbd_negotiate_options(NBDClient *client)
                 }
                 break;
             default:
-                if (nbd_negotiate_drop_sync(client->ioc, length) < 0) {
+                if (drop_sync(client->ioc, length, NULL) < 0) {
                     return -EIO;
                 }
                 ret = nbd_negotiate_send_rep_err(client->ioc,
@@ -656,12 +593,12 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data)
             TRACE("TLS cannot be enabled with oldstyle protocol");
             goto fail;
         }
-        if (nbd_negotiate_write(client->ioc, buf, sizeof(buf)) < 0) {
+        if (write_sync(client->ioc, buf, sizeof(buf), NULL) < 0) {
             LOG("write failed");
             goto fail;
         }
     } else {
-        if (nbd_negotiate_write(client->ioc, buf, 18) < 0) {
+        if (write_sync(client->ioc, buf, 18, NULL) < 0) {
             LOG("write failed");
             goto fail;
         }
@@ -676,7 +613,7 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data)
         stq_be_p(buf + 18, client->exp->size);
         stw_be_p(buf + 26, client->exp->nbdflags | myflags);
         len = client->no_zeroes ? 10 : sizeof(buf) - 18;
-        if (nbd_negotiate_write(client->ioc, buf + 18, len) < 0) {
+        if (write_sync(client->ioc, buf + 18, len, NULL) < 0) {
             LOG("write failed");
             goto fail;
         }
-- 
2.11.1