Use new qemu_iovec_init_buf() instead of
qemu_iovec_init_external( ... , 1), which simplifies the code.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qed-table.c | 16 +++-------------
 block/qed.c       | 31 +++++++++----------------------
 2 files changed, 12 insertions(+), 35 deletions(-)

diff --git a/block/qed-table.c b/block/qed-table.c
index 7df5680adb..c497bd4aec 100644
--- a/block/qed-table.c
+++ b/block/qed-table.c
@@ -21,16 +21,11 @@
 /* Called with table_lock held.  */
 static int qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table)
 {
-    QEMUIOVector qiov;
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(
+        qiov, table->offsets, s->header.cluster_size * s->header.table_size);
     int noffsets;
     int i, ret;
 
-    struct iovec iov = {
-        .iov_base = table->offsets,
-        .iov_len = s->header.cluster_size * s->header.table_size,
-    };
-    qemu_iovec_init_external(&qiov, &iov, 1);
-
     trace_qed_read_table(s, offset, table);
 
     qemu_co_mutex_unlock(&s->table_lock);
@@ -71,7 +66,6 @@ static int qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
     unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;
     unsigned int start, end, i;
     QEDTable *new_table;
-    struct iovec iov;
     QEMUIOVector qiov;
     size_t len_bytes;
     int ret;
@@ -85,11 +79,7 @@ static int qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
     len_bytes = (end - start) * sizeof(uint64_t);
 
     new_table = qemu_blockalign(s->bs, len_bytes);
-    iov = (struct iovec) {
-        .iov_base = new_table->offsets,
-        .iov_len = len_bytes,
-    };
-    qemu_iovec_init_external(&qiov, &iov, 1);
+    qemu_iovec_init_buf(&qiov, new_table->offsets, len_bytes);
 
     /* Byteswap table */
     for (i = start; i < end; i++) {
diff --git a/block/qed.c b/block/qed.c
index 1280870024..a010e5b349 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -113,18 +113,13 @@ static int coroutine_fn qed_write_header(BDRVQEDState *s)
     int nsectors = DIV_ROUND_UP(sizeof(QEDHeader), BDRV_SECTOR_SIZE);
     size_t len = nsectors * BDRV_SECTOR_SIZE;
     uint8_t *buf;
-    struct iovec iov;
     QEMUIOVector qiov;
     int ret;
 
     assert(s->allocating_acb || s->allocating_write_reqs_plugged);
 
     buf = qemu_blockalign(s->bs, len);
-    iov = (struct iovec) {
-        .iov_base = buf,
-        .iov_len = len,
-    };
-    qemu_iovec_init_external(&qiov, &iov, 1);
+    qemu_iovec_init_buf(&qiov, buf, len);
 
     ret = bdrv_co_preadv(s->bs->file, 0, qiov.size, &qiov, 0);
     if (ret < 0) {
@@ -913,7 +908,6 @@ static int coroutine_fn qed_copy_from_backing_file(BDRVQEDState *s,
 {
     QEMUIOVector qiov;
     QEMUIOVector *backing_qiov = NULL;
-    struct iovec iov;
     int ret;
 
     /* Skip copy entirely if there is no work to do */
@@ -921,11 +915,7 @@ static int coroutine_fn qed_copy_from_backing_file(BDRVQEDState *s,
         return 0;
     }
 
-    iov = (struct iovec) {
-        .iov_base = qemu_blockalign(s->bs, len),
-        .iov_len = len,
-    };
-    qemu_iovec_init_external(&qiov, &iov, 1);
+    qemu_iovec_init_buf(&qiov, qemu_blockalign(s->bs, len), len);
 
     ret = qed_read_backing_file(s, pos, &qiov, &backing_qiov);
 
@@ -946,7 +936,7 @@ static int coroutine_fn qed_copy_from_backing_file(BDRVQEDState *s,
     }
     ret = 0;
 out:
-    qemu_vfree(iov.iov_base);
+    qemu_vfree(qemu_iovec_get_buf(&qiov));
     return ret;
 }
 
@@ -1447,8 +1437,12 @@ static int coroutine_fn bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs,
                                                   BdrvRequestFlags flags)
 {
     BDRVQEDState *s = bs->opaque;
-    QEMUIOVector qiov;
-    struct iovec iov;
+
+    /*
+     * Zero writes start without an I/O buffer.  If a buffer becomes necessary
+     * then it will be allocated during request processing.
+     */
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, bytes);
 
     /* Fall back if the request is not aligned */
     if (qed_offset_into_cluster(s, offset) ||
@@ -1456,13 +1450,6 @@ static int coroutine_fn bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs,
         return -ENOTSUP;
     }
 
-    /* Zero writes start without an I/O buffer.  If a buffer becomes necessary
-     * then it will be allocated during request processing.
-     */
-    iov.iov_base = NULL;
-    iov.iov_len = bytes;
-
-    qemu_iovec_init_external(&qiov, &iov, 1);
     return qed_co_request(bs, offset >> BDRV_SECTOR_BITS, &qiov,
                           bytes >> BDRV_SECTOR_BITS,
                           QED_AIOCB_WRITE | QED_AIOCB_ZERO);
-- 
2.18.0

On 2/7/19 4:24 AM, Vladimir Sementsov-Ogievskiy wrote:
> Use new qemu_iovec_init_buf() instead of
> qemu_iovec_init_external( ... , 1), which simplifies the code.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/qed-table.c | 16 +++-------------
>  block/qed.c       | 31 +++++++++----------------------
>  2 files changed, 12 insertions(+), 35 deletions(-)
> 

> @@ -921,11 +915,7 @@ static int coroutine_fn qed_copy_from_backing_file(BDRVQEDState *s,
>          return 0;
>      }
>  
> -    iov = (struct iovec) {
> -        .iov_base = qemu_blockalign(s->bs, len),
> -        .iov_len = len,
> -    };
> -    qemu_iovec_init_external(&qiov, &iov, 1);
> +    qemu_iovec_init_buf(&qiov, qemu_blockalign(s->bs, len), len);
>  
>      ret = qed_read_backing_file(s, pos, &qiov, &backing_qiov);
>  
> @@ -946,7 +936,7 @@ static int coroutine_fn qed_copy_from_backing_file(BDRVQEDState *s,
>      }
>      ret = 0;
>  out:
> -    qemu_vfree(iov.iov_base);
> +    qemu_vfree(qemu_iovec_get_buf(&qiov));

Matching my comments on 7/17, a separate variable to hold the allocated
buffer may mean that you don't need qemu_iovec_get_buf().

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org