migration: remove the QEMUFileOps 'get_buffer' callback

This directly implements the get_buffer logic using QIOChannel APIs.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  dgilbert: Fixup len = *-*EIO as spotted by Peter Xu

3 files changed, 16 insertions, 40 deletions

diff --git a/migration/qemu-file-channel.c b/migration/qemu-file-channel.c
index 8ff58e81f9..7b32831752 100644
--- a/migration/qemu-file-channel.c
+++ b/migration/qemu-file-channel.c
@@ -74,34 +74,6 @@ static ssize_t channel_writev_buffer(void *opaque,
 }
 
 
-static ssize_t channel_get_buffer(void *opaque,
-                                  uint8_t *buf,
-                                  int64_t pos,
-                                  size_t size,
-                                  Error **errp)
-{
-    QIOChannel *ioc = QIO_CHANNEL(opaque);
-    ssize_t ret;
-
-    do {
-        ret = qio_channel_read(ioc, (char *)buf, size, errp);
-        if (ret < 0) {
-            if (ret == QIO_CHANNEL_ERR_BLOCK) {
-                if (qemu_in_coroutine()) {
-                    qio_channel_yield(ioc, G_IO_IN);
-                } else {
-                    qio_channel_wait(ioc, G_IO_IN);
-                }
-            } else {
-                return -EIO;
-            }
-        }
-    } while (ret == QIO_CHANNEL_ERR_BLOCK);
-
-    return ret;
-}
-
-
 static QEMUFile *channel_get_input_return_path(void *opaque)
 {
     QIOChannel *ioc = QIO_CHANNEL(opaque);
@@ -117,7 +89,6 @@ static QEMUFile *channel_get_output_return_path(void *opaque)
 }
 
 static const QEMUFileOps channel_input_ops = {
-    .get_buffer = channel_get_buffer,
     .get_return_path = channel_get_input_return_path,
 };
 
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index 74f919de67..2f46873efd 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -377,8 +377,22 @@ static ssize_t qemu_fill_buffer(QEMUFile *f)
         return 0;
     }
 
-    len = f->ops->get_buffer(f->ioc, f->buf + pending, f->total_transferred,
-                             IO_BUF_SIZE - pending, &local_error);
+    do {
+        len = qio_channel_read(f->ioc,
+                               (char *)f->buf + pending,
+                               IO_BUF_SIZE - pending,
+                               &local_error);
+        if (len == QIO_CHANNEL_ERR_BLOCK) {
+            if (qemu_in_coroutine()) {
+                qio_channel_yield(f->ioc, G_IO_IN);
+            } else {
+                qio_channel_wait(f->ioc, G_IO_IN);
+            }
+        } else if (len < 0) {
+            len = -EIO;
+        }
+    } while (len == QIO_CHANNEL_ERR_BLOCK);
+
     if (len > 0) {
         f->buf_size += len;
         f->total_transferred += len;
diff --git a/migration/qemu-file.h b/migration/qemu-file.h
index 4a3beedb5b..f7ed568894 100644
--- a/migration/qemu-file.h
+++ b/migration/qemu-file.h
@@ -29,14 +29,6 @@
 #include "exec/cpu-common.h"
 #include "io/channel.h"
 
-/* Read a chunk of data from a file at the given position.  The pos argument
- * can be ignored if the file is only be used for streaming.  The number of
- * bytes actually read should be returned.
- */
-typedef ssize_t (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
-                                        int64_t pos, size_t size,
-                                        Error **errp);
-
 /*
  * This function writes an iovec to file. The handler must write all
  * of the data or return a negative errno value.
@@ -77,7 +69,6 @@ typedef size_t (QEMURamSaveFunc)(QEMUFile *f,
 typedef QEMUFile *(QEMURetPathFunc)(void *opaque);
 
 typedef struct QEMUFileOps {
-    QEMUFileGetBufferFunc *get_buffer;
     QEMUFileWritevBufferFunc *writev_buffer;
     QEMURetPathFunc *get_return_path;
 } QEMUFileOps;