Re: [Qemu-devel] [PATCH 2/6] block: Make .bdrv_load_vmstate() vectored

[Eric Blake]

On 06/10/2016 10:05 AM, Kevin Wolf wrote:
> This brings it in line with .bdrv_save_vmstate().
> 
> Signed-off-by: Kevin Wolf 
> ---
>  block/io.c| 26 +-
>  block/qcow2.c |  6 +++---
>  block/sheepdog.c  | 13 ++---
>  include/block/block.h |  1 +
>  include/block/block_int.h |  4 ++--
>  5 files changed, 37 insertions(+), 13 deletions(-)
> 
> diff --git a/block/io.c b/block/io.c
> index 11510cf..602c7d3 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -1862,13 +1862,29 @@ int bdrv_writev_vmstate(BlockDriverState *bs, 
> QEMUIOVector *qiov, int64_t pos)
>  int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
>int64_t pos, int size)
>  {
> +QEMUIOVector qiov;
> +struct iovec iov = {
> +.iov_base   = buf,
> +.iov_len= size,
> +};
> +int ret;

Dead variable.

> +
> +qemu_iovec_init_external(, , 1);
> +return bdrv_readv_vmstate(bs, , pos);
> +}
> +
> +int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
> +{
>  BlockDriver *drv = bs->drv;
> -if (!drv)
> +
> +if (!drv) {
>  return -ENOMEDIUM;
> -if (drv->bdrv_load_vmstate)
> -return drv->bdrv_load_vmstate(bs, buf, pos, size);
> -if (bs->file)
> -return bdrv_load_vmstate(bs->file->bs, buf, pos, size);
> +} else if (drv->bdrv_load_vmstate) {
> +return drv->bdrv_load_vmstate(bs, qiov, pos);
> +} else if (bs->file) {
> +return bdrv_readv_vmstate(bs->file->bs, qiov, pos);
> +}

Don't know that I would have used 'else if' after a return, but it's not
wrong, so no need to change.

With the dead 'ret' gone,
Reviewed-by: Eric Blake 

-- 
Eric Blake   eblake redhat com+1-919-301-3266
Libvirt virtualization library http://libvirt.org



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[Qemu-devel] [PATCH 2/6] block: Make .bdrv_load_vmstate() vectored

[Kevin Wolf]

This brings it in line with .bdrv_save_vmstate().

Signed-off-by: Kevin Wolf 
---
 block/io.c| 26 +-
 block/qcow2.c |  6 +++---
 block/sheepdog.c  | 13 ++---
 include/block/block.h |  1 +
 include/block/block_int.h |  4 ++--
 5 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/block/io.c b/block/io.c
index 11510cf..602c7d3 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1862,13 +1862,29 @@ int bdrv_writev_vmstate(BlockDriverState *bs, 
QEMUIOVector *qiov, int64_t pos)
 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
   int64_t pos, int size)
 {
+QEMUIOVector qiov;
+struct iovec iov = {
+.iov_base   = buf,
+.iov_len= size,
+};
+int ret;
+
+qemu_iovec_init_external(, , 1);
+return bdrv_readv_vmstate(bs, , pos);
+}
+
+int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
+{
 BlockDriver *drv = bs->drv;
-if (!drv)
+
+if (!drv) {
 return -ENOMEDIUM;
-if (drv->bdrv_load_vmstate)
-return drv->bdrv_load_vmstate(bs, buf, pos, size);
-if (bs->file)
-return bdrv_load_vmstate(bs->file->bs, buf, pos, size);
+} else if (drv->bdrv_load_vmstate) {
+return drv->bdrv_load_vmstate(bs, qiov, pos);
+} else if (bs->file) {
+return bdrv_readv_vmstate(bs->file->bs, qiov, pos);
+}
+
 return -ENOTSUP;
 }
 
diff --git a/block/qcow2.c b/block/qcow2.c
index cb55e2d..72ae2bf 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2920,8 +2920,8 @@ static int qcow2_save_vmstate(BlockDriverState *bs, 
QEMUIOVector *qiov,
 return ret;
 }
 
-static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf,
-  int64_t pos, int size)
+static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
+  int64_t pos)
 {
 BDRVQcow2State *s = bs->opaque;
 bool zero_beyond_eof = bs->zero_beyond_eof;
@@ -2929,7 +2929,7 @@ static int qcow2_load_vmstate(BlockDriverState *bs, 
uint8_t *buf,
 
 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
 bs->zero_beyond_eof = false;
-ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size);
+ret = bdrv_preadv(bs, qcow2_vm_state_offset(s) + pos, qiov);
 bs->zero_beyond_eof = zero_beyond_eof;
 
 return ret;
diff --git a/block/sheepdog.c b/block/sheepdog.c
index 23fbace..ef5d044 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -2784,12 +2784,19 @@ static int sd_save_vmstate(BlockDriverState *bs, 
QEMUIOVector *qiov,
 return ret;
 }
 
-static int sd_load_vmstate(BlockDriverState *bs, uint8_t *data,
-   int64_t pos, int size)
+static int sd_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
+   int64_t pos)
 {
 BDRVSheepdogState *s = bs->opaque;
+void *buf;
+int ret;
 
-return do_load_save_vmstate(s, data, pos, size, 1);
+buf = qemu_blockalign(bs, qiov->size);
+ret = do_load_save_vmstate(s, buf, pos, qiov->size, 1);
+qemu_iovec_from_buf(qiov, 0, buf, qiov->size);
+qemu_vfree(buf);
+
+return ret;
 }
 
 
diff --git a/include/block/block.h b/include/block/block.h
index aca7f23..a158575 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -428,6 +428,7 @@ void path_combine(char *dest, int dest_size,
   const char *base_path,
   const char *filename);
 
+int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
   int64_t pos, int size);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 8a4963c..f9a32cc 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -226,8 +226,8 @@ struct BlockDriver {
 
 int (*bdrv_save_vmstate)(BlockDriverState *bs, QEMUIOVector *qiov,
  int64_t pos);
-int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf,
- int64_t pos, int size);
+int (*bdrv_load_vmstate)(BlockDriverState *bs, QEMUIOVector *qiov,
+ int64_t pos);
 
 int (*bdrv_change_backing_file)(BlockDriverState *bs,
 const char *backing_file, const char *backing_fmt);
-- 
1.8.3.1