Re: [Qemu-block] [PATCH v2 09/13] block/backup: remove yield_and_check

[Max Reitz]

On 2018-01-19 21:58, John Snow wrote:
> This is a respin of the same functionality as mirror_throttle,
> so trash this and replace it with the generic version.
> 
> yield_and_check returned true if canceled, false otherwise.
> block_job_relax returns -ECANCELED if canceled, 0 otherwise.
> 
> Signed-off-by: John Snow 
> ---
>  block/backup.c | 20 
>  1 file changed, 4 insertions(+), 16 deletions(-)
> 
> diff --git a/block/backup.c b/block/backup.c
> index b4204c0ee4..0624c3b322 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -334,29 +334,17 @@ static void backup_complete(BlockJob *job, void *opaque)
>  g_free(data);
>  }
>  
> -static bool coroutine_fn yield_and_check(BackupBlockJob *job)
> +static uint64_t get_delay_ns(BackupBlockJob *job)
>  {
>  uint64_t delay_ns = 0;
>  
> -if (block_job_is_cancelled(>common)) {
> -return true;
> -}
> -
> -/* we need to yield so that bdrv_drain_all() returns.
> - * (without, VM does not reboot)
> - */
>  if (job->common.speed) {
>  delay_ns = ratelimit_calculate_delay(>limit,
>   job->bytes_read);
>  job->bytes_read = 0;
>  }
>  
> -block_job_relax(>common, delay_ns);
> -if (block_job_is_cancelled(>common)) {
> -return true;
> -}
> -
> -return false;
> +return delay_ns;
>  }
>  
>  static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
> @@ -369,7 +357,7 @@ static int coroutine_fn 
> backup_run_incremental(BackupBlockJob *job)
>  hbitmap_iter_init(, job->copy_bitmap, 0);
>  while ((cluster = hbitmap_iter_next()) != -1) {
>  do {
> -if (yield_and_check(job)) {
> +if (block_job_relax(>common, get_delay_ns(job))) {
>  return 0;
>  }
>  ret = backup_do_cow(job, cluster * job->cluster_size,
> @@ -465,7 +453,7 @@ static void coroutine_fn backup_run(void *opaque)
>  bool error_is_read;
>  int alloced = 0;
>  
> -if (yield_and_check(job)) {
> +if (block_job_relax(>common, get_delay_ns(job))) {
>  break;
>  }
>  
> 

I'd very much prefer an explicit block_job_relax(...) == -ECANCELED, I
have to say.

If you coerce me, I can give an R-b, but you'll have to wrest it from me
by force!

Max



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[Qemu-block] [PATCH v2 09/13] block/backup: remove yield_and_check

[John Snow]

This is a respin of the same functionality as mirror_throttle,
so trash this and replace it with the generic version.

yield_and_check returned true if canceled, false otherwise.
block_job_relax returns -ECANCELED if canceled, 0 otherwise.

Signed-off-by: John Snow 
---
 block/backup.c | 20 
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/block/backup.c b/block/backup.c
index b4204c0ee4..0624c3b322 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -334,29 +334,17 @@ static void backup_complete(BlockJob *job, void *opaque)
 g_free(data);
 }
 
-static bool coroutine_fn yield_and_check(BackupBlockJob *job)
+static uint64_t get_delay_ns(BackupBlockJob *job)
 {
 uint64_t delay_ns = 0;
 
-if (block_job_is_cancelled(>common)) {
-return true;
-}
-
-/* we need to yield so that bdrv_drain_all() returns.
- * (without, VM does not reboot)
- */
 if (job->common.speed) {
 delay_ns = ratelimit_calculate_delay(>limit,
  job->bytes_read);
 job->bytes_read = 0;
 }
 
-block_job_relax(>common, delay_ns);
-if (block_job_is_cancelled(>common)) {
-return true;
-}
-
-return false;
+return delay_ns;
 }
 
 static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
@@ -369,7 +357,7 @@ static int coroutine_fn 
backup_run_incremental(BackupBlockJob *job)
 hbitmap_iter_init(, job->copy_bitmap, 0);
 while ((cluster = hbitmap_iter_next()) != -1) {
 do {
-if (yield_and_check(job)) {
+if (block_job_relax(>common, get_delay_ns(job))) {
 return 0;
 }
 ret = backup_do_cow(job, cluster * job->cluster_size,
@@ -465,7 +453,7 @@ static void coroutine_fn backup_run(void *opaque)
 bool error_is_read;
 int alloced = 0;
 
-if (yield_and_check(job)) {
+if (block_job_relax(>common, get_delay_ns(job))) {
 break;
 }
 
-- 
2.14.3