Re: [Qemu-block] [PATCH v3 06/20] commit: Switch commit_run() to byte-based

[Kevin Wolf]

Am 27.06.2017 um 21:24 hat Eric Blake geschrieben:
> We are gradually converting to byte-based interfaces, as they are
> easier to reason about than sector-based.  Change the internal
> loop iteration of committing to track by bytes instead of sectors
> (although we are still guaranteed that we iterate by steps that
> are sector-aligned).
> 
> Signed-off-by: Eric Blake 
> Reviewed-by: John Snow 

Reviewed-by: Kevin Wolf 

Re: [Qemu-block] [PATCH v3 06/20] commit: Switch commit_run() to byte-based

[Jeff Cody]

On Tue, Jun 27, 2017 at 02:24:44PM -0500, Eric Blake wrote:
> We are gradually converting to byte-based interfaces, as they are
> easier to reason about than sector-based.  Change the internal
> loop iteration of committing to track by bytes instead of sectors
> (although we are still guaranteed that we iterate by steps that
> are sector-aligned).
> 
> Signed-off-by: Eric Blake 
> Reviewed-by: John Snow 
> 

Reviewed-by: Jeff Cody 

> ---
> v2: no change
> ---
>  block/commit.c | 16 ++--
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/block/commit.c b/block/commit.c
> index 6f67d78..c3a7bca 100644
> --- a/block/commit.c
> +++ b/block/commit.c
> @@ -143,17 +143,16 @@ static void coroutine_fn commit_run(void *opaque)
>  {
>  CommitBlockJob *s = opaque;
>  CommitCompleteData *data;
> -int64_t sector_num, end;
> +int64_t offset;
>  uint64_t delay_ns = 0;
>  int ret = 0;
> -int n = 0;
> +int n = 0; /* sectors */
>  void *buf = NULL;
>  int bytes_written = 0;
>  int64_t base_len;
> 
>  ret = s->common.len = blk_getlength(s->top);
> 
> -
>  if (s->common.len < 0) {
>  goto out;
>  }
> @@ -170,10 +169,9 @@ static void coroutine_fn commit_run(void *opaque)
>  }
>  }
> 
> -end = s->common.len >> BDRV_SECTOR_BITS;
>  buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
> 
> -for (sector_num = 0; sector_num < end; sector_num += n) {
> +for (offset = 0; offset < s->common.len; offset += n * BDRV_SECTOR_SIZE) 
> {
>  bool copy;
> 
>  /* Note that even when no rate limit is applied we need to yield
> @@ -185,15 +183,13 @@ static void coroutine_fn commit_run(void *opaque)
>  }
>  /* Copy if allocated above the base */
>  ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base),
> -  sector_num,
> +  offset / BDRV_SECTOR_SIZE,
>COMMIT_BUFFER_SIZE / BDRV_SECTOR_SIZE,
>);
>  copy = (ret == 1);
> -trace_commit_one_iteration(s, sector_num * BDRV_SECTOR_SIZE,
> -   n * BDRV_SECTOR_SIZE, ret);
> +trace_commit_one_iteration(s, offset, n * BDRV_SECTOR_SIZE, ret);
>  if (copy) {
> -ret = commit_populate(s->top, s->base,
> -  sector_num * BDRV_SECTOR_SIZE,
> +ret = commit_populate(s->top, s->base, offset,
>n * BDRV_SECTOR_SIZE, buf);
>  bytes_written += n * BDRV_SECTOR_SIZE;
>  }
> -- 
> 2.9.4
> 

[Qemu-block] [PATCH v3 06/20] commit: Switch commit_run() to byte-based

[Eric Blake]

We are gradually converting to byte-based interfaces, as they are
easier to reason about than sector-based.  Change the internal
loop iteration of committing to track by bytes instead of sectors
(although we are still guaranteed that we iterate by steps that
are sector-aligned).

Signed-off-by: Eric Blake 
Reviewed-by: John Snow 

---
v2: no change
---
 block/commit.c | 16 ++--
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/block/commit.c b/block/commit.c
index 6f67d78..c3a7bca 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -143,17 +143,16 @@ static void coroutine_fn commit_run(void *opaque)
 {
 CommitBlockJob *s = opaque;
 CommitCompleteData *data;
-int64_t sector_num, end;
+int64_t offset;
 uint64_t delay_ns = 0;
 int ret = 0;
-int n = 0;
+int n = 0; /* sectors */
 void *buf = NULL;
 int bytes_written = 0;
 int64_t base_len;

 ret = s->common.len = blk_getlength(s->top);

-
 if (s->common.len < 0) {
 goto out;
 }
@@ -170,10 +169,9 @@ static void coroutine_fn commit_run(void *opaque)
 }
 }

-end = s->common.len >> BDRV_SECTOR_BITS;
 buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);

-for (sector_num = 0; sector_num < end; sector_num += n) {
+for (offset = 0; offset < s->common.len; offset += n * BDRV_SECTOR_SIZE) {
 bool copy;

 /* Note that even when no rate limit is applied we need to yield
@@ -185,15 +183,13 @@ static void coroutine_fn commit_run(void *opaque)
 }
 /* Copy if allocated above the base */
 ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base),
-  sector_num,
+  offset / BDRV_SECTOR_SIZE,
   COMMIT_BUFFER_SIZE / BDRV_SECTOR_SIZE,
   );
 copy = (ret == 1);
-trace_commit_one_iteration(s, sector_num * BDRV_SECTOR_SIZE,
-   n * BDRV_SECTOR_SIZE, ret);
+trace_commit_one_iteration(s, offset, n * BDRV_SECTOR_SIZE, ret);
 if (copy) {
-ret = commit_populate(s->top, s->base,
-  sector_num * BDRV_SECTOR_SIZE,
+ret = commit_populate(s->top, s->base, offset,
   n * BDRV_SECTOR_SIZE, buf);
 bytes_written += n * BDRV_SECTOR_SIZE;
 }
-- 
2.9.4