[Qemu-devel] [PATCH FYI 46/46] migration: remove support for non-iovec based write handlers

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

All the remaining QEMUFile implementations provide an iovec
based write handler, so the put_buffer callback can be removed
to simplify the code.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/migration/qemu-file.h |  9 ---------
 migration/qemu-file.c         | 36 ++++++++----------------------------
 migration/savevm.c            |  8 --------
 3 files changed, 8 insertions(+), 45 deletions(-)

diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
index ce6b421..a603efc 100644
--- a/include/migration/qemu-file.h
+++ b/include/migration/qemu-file.h
@@ -29,14 +29,6 @@
 
 #include <stdint.h>
 
-/* This function writes a chunk of data to a file at the given position.
- * The pos argument can be ignored if the file is only being used for
- * streaming.  The handler must write all of the data or return a negative
- * errno value.
- */
-typedef int (QEMUFilePutBufferFunc)(void *opaque, const uint8_t *buf,
-                                    int64_t pos, int size);
-
 /* 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.
@@ -105,7 +97,6 @@ typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque,
 typedef int (QEMUFileShutdownFunc)(void *opaque, bool rd, bool wr);
 
 typedef struct QEMUFileOps {
-    QEMUFilePutBufferFunc *put_buffer;
     QEMUFileGetBufferFunc *get_buffer;
     QEMUFileCloseFunc *close;
     QEMUFileGetFD *get_fd;
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index c8b0b79..573dd73 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -116,7 +116,7 @@ void qemu_file_set_error(QEMUFile *f, int ret)
 
 bool qemu_file_is_writable(QEMUFile *f)
 {
-    return f->ops->writev_buffer || f->ops->put_buffer;
+    return f->ops->writev_buffer;
 }
 
 /**
@@ -135,16 +135,9 @@ void qemu_fflush(QEMUFile *f)
         return;
     }
 
-    if (f->ops->writev_buffer) {
-        if (f->iovcnt > 0) {
-            expect = iov_size(f->iov, f->iovcnt);
-            ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos);
-        }
-    } else {
-        if (f->buf_index > 0) {
-            expect = f->buf_index;
-            ret = f->ops->put_buffer(f->opaque, f->buf, f->pos, f->buf_index);
-        }
+    if (f->iovcnt > 0) {
+        expect = iov_size(f->iov, f->iovcnt);
+        ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos);
     }
 
     if (ret >= 0) {
@@ -339,11 +332,6 @@ static void add_to_iovec(QEMUFile *f, const uint8_t *buf, int size)
 
 void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size)
 {
-    if (!f->ops->writev_buffer) {
-        qemu_put_buffer(f, buf, size);
-        return;
-    }
-
     if (f->last_error) {
         return;
     }
@@ -367,9 +355,7 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
         }
         memcpy(f->buf + f->buf_index, buf, l);
         f->bytes_xfer += l;
-        if (f->ops->writev_buffer) {
-            add_to_iovec(f, f->buf + f->buf_index, l);
-        }
+        add_to_iovec(f, f->buf + f->buf_index, l);
         f->buf_index += l;
         if (f->buf_index == IO_BUF_SIZE) {
             qemu_fflush(f);
@@ -390,9 +376,7 @@ void qemu_put_byte(QEMUFile *f, int v)
 
     f->buf[f->buf_index] = v;
     f->bytes_xfer++;
-    if (f->ops->writev_buffer) {
-        add_to_iovec(f, f->buf + f->buf_index, 1);
-    }
+    add_to_iovec(f, f->buf + f->buf_index, 1);
     f->buf_index++;
     if (f->buf_index == IO_BUF_SIZE) {
         qemu_fflush(f);
@@ -519,12 +503,8 @@ int64_t qemu_ftell_fast(QEMUFile *f)
     int64_t ret = f->pos;
     int i;
 
-    if (f->ops->writev_buffer) {
-        for (i = 0; i < f->iovcnt; i++) {
-            ret += f->iov[i].iov_len;
-        }
-    } else {
-        ret += f->buf_index;
+    for (i = 0; i < f->iovcnt; i++) {
+        ret += f->iov[i].iov_len;
     }
 
     return ret;
diff --git a/migration/savevm.c b/migration/savevm.c
index 82febef..d1116f2 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -139,13 +139,6 @@ static ssize_t block_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
     return qiov.size;
 }
 
-static int block_put_buffer(void *opaque, const uint8_t *buf,
-                           int64_t pos, int size)
-{
-    bdrv_save_vmstate(opaque, buf, pos, size);
-    return size;
-}
-
 static int block_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
 {
     return bdrv_load_vmstate(opaque, buf, pos, size);
@@ -162,7 +155,6 @@ static const QEMUFileOps bdrv_read_ops = {
 };
 
 static const QEMUFileOps bdrv_write_ops = {
-    .put_buffer     = block_put_buffer,
     .writev_buffer  = block_writev_buffer,
     .close          = bdrv_fclose
 };
-- 
2.4.3