[PATCH v2 19/21] migration: remove the QEMUFileOps 'writev_buffer' callback

["Daniel P. Berrangé" <berrange@redhat.com>]

This directly implements the writev_buffer logic using QIOChannel APIs.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 migration/qemu-file-channel.c | 43 -----------------------------------
 migration/qemu-file.c         | 24 +++++++------------
 migration/qemu-file.h         |  9 --------
 3 files changed, 8 insertions(+), 68 deletions(-)

diff --git a/migration/qemu-file-channel.c b/migration/qemu-file-channel.c
index 7b32831752..2e139f7bcd 100644
--- a/migration/qemu-file-channel.c
+++ b/migration/qemu-file-channel.c
@@ -32,48 +32,6 @@
 #include "yank_functions.h"
 
 
-static ssize_t channel_writev_buffer(void *opaque,
-                                     struct iovec *iov,
-                                     int iovcnt,
-                                     int64_t pos,
-                                     Error **errp)
-{
-    QIOChannel *ioc = QIO_CHANNEL(opaque);
-    ssize_t done = 0;
-    struct iovec *local_iov = g_new(struct iovec, iovcnt);
-    struct iovec *local_iov_head = local_iov;
-    unsigned int nlocal_iov = iovcnt;
-
-    nlocal_iov = iov_copy(local_iov, nlocal_iov,
-                          iov, iovcnt,
-                          0, iov_size(iov, iovcnt));
-
-    while (nlocal_iov > 0) {
-        ssize_t len;
-        len = qio_channel_writev(ioc, local_iov, nlocal_iov, errp);
-        if (len == QIO_CHANNEL_ERR_BLOCK) {
-            if (qemu_in_coroutine()) {
-                qio_channel_yield(ioc, G_IO_OUT);
-            } else {
-                qio_channel_wait(ioc, G_IO_OUT);
-            }
-            continue;
-        }
-        if (len < 0) {
-            done = -EIO;
-            goto cleanup;
-        }
-
-        iov_discard_front(&local_iov, &nlocal_iov, len);
-        done += len;
-    }
-
- cleanup:
-    g_free(local_iov_head);
-    return done;
-}
-
-
 static QEMUFile *channel_get_input_return_path(void *opaque)
 {
     QIOChannel *ioc = QIO_CHANNEL(opaque);
@@ -94,7 +52,6 @@ static const QEMUFileOps channel_input_ops = {
 
 
 static const QEMUFileOps channel_output_ops = {
-    .writev_buffer = channel_writev_buffer,
     .get_return_path = channel_get_output_return_path,
 };
 
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index df438724cd..b787dabff7 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -248,10 +248,6 @@ static void qemu_iovec_release_ram(QEMUFile *f)
  */
 void qemu_fflush(QEMUFile *f)
 {
-    ssize_t ret = 0;
-    ssize_t expect = 0;
-    Error *local_error = NULL;
-
     if (!qemu_file_is_writable(f)) {
         return;
     }
@@ -260,22 +256,18 @@ void qemu_fflush(QEMUFile *f)
         return;
     }
     if (f->iovcnt > 0) {
-        expect = iov_size(f->iov, f->iovcnt);
-        ret = f->ops->writev_buffer(f->ioc, f->iov, f->iovcnt, f->total_transferred,
-                                    &local_error);
+        Error *local_error = NULL;
+        if (qio_channel_writev_all(f->ioc,
+                                   f->iov, f->iovcnt,
+                                   &local_error) < 0) {
+            qemu_file_set_error_obj(f, -EIO, local_error);
+        } else {
+            f->total_transferred += iov_size(f->iov, f->iovcnt);
+        }
 
         qemu_iovec_release_ram(f);
     }
 
-    if (ret >= 0) {
-        f->total_transferred += ret;
-    }
-    /* We expect the QEMUFile write impl to send the full
-     * data set we requested, so sanity check that.
-     */
-    if (ret != expect) {
-        qemu_file_set_error_obj(f, ret < 0 ? ret : -EIO, local_error);
-    }
     f->buf_index = 0;
     f->iovcnt = 0;
 }
diff --git a/migration/qemu-file.h b/migration/qemu-file.h
index f7ed568894..de3f066014 100644
--- a/migration/qemu-file.h
+++ b/migration/qemu-file.h
@@ -29,14 +29,6 @@
 #include "exec/cpu-common.h"
 #include "io/channel.h"
 
-/*
- * This function writes an iovec to file. The handler must write all
- * of the data or return a negative errno value.
- */
-typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
-                                           int iovcnt, int64_t pos,
-                                           Error **errp);
-
 /*
  * This function provides hooks around different
  * stages of RAM migration.
@@ -69,7 +61,6 @@ typedef size_t (QEMURamSaveFunc)(QEMUFile *f,
 typedef QEMUFile *(QEMURetPathFunc)(void *opaque);
 
 typedef struct QEMUFileOps {
-    QEMUFileWritevBufferFunc *writev_buffer;
     QEMURetPathFunc *get_return_path;
 } QEMUFileOps;
 
-- 
2.36.1