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block: get rid of bdrv_io_unplugged_begin/end 

bdrv_io_plug and bdrv_io_unplug are only called (via their
BlockBackend equivalents) after starting asynchronous I/O.
bdrv_drain is not going to be called while they are running,
because---even if a coroutine runs for some reason---it will
only drain in the next iteration of the event loop through
bdrv_co_yield_to_drain.

So this mechanism is unnecessary, get rid of it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161129113334.605-1-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-11-29 12:33:34 +01:00 committed by Stefan Hajnoczi
parent 2ccede18bd
commit 8f90b5e91d
3 changed files with 3 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
block/io.c
View File

@ -228,9 +228,7 @@ void bdrv_drained_begin(BlockDriverState *bs)
bdrv_parent_drained_begin(bs);
}
bdrv_io_unplugged_begin(bs);
bdrv_drain_recurse(bs);
bdrv_io_unplugged_end(bs);
}
void bdrv_drained_end(BlockDriverState *bs)
@ -302,7 +300,6 @@ void bdrv_drain_all_begin(void)
aio_context_acquire(aio_context);
bdrv_parent_drained_begin(bs);
bdrv_io_unplugged_begin(bs);
aio_disable_external(aio_context);
aio_context_release(aio_context);
@ -347,7 +344,6 @@ void bdrv_drain_all_end(void)
aio_context_acquire(aio_context);
aio_enable_external(aio_context);
bdrv_io_unplugged_end(bs);
bdrv_parent_drained_end(bs);
aio_context_release(aio_context);
}
@ -2650,7 +2646,7 @@ void bdrv_io_plug(BlockDriverState *bs)
bdrv_io_plug(child->bs);
}
if (bs->io_plugged++ == 0 && bs->io_plug_disabled == 0) {
if (bs->io_plugged++ == 0) {
BlockDriver *drv = bs->drv;
if (drv && drv->bdrv_io_plug) {
drv->bdrv_io_plug(bs);
@ -2663,7 +2659,7 @@ void bdrv_io_unplug(BlockDriverState *bs)
BdrvChild *child;
assert(bs->io_plugged);
if (--bs->io_plugged == 0 && bs->io_plug_disabled == 0) {
if (--bs->io_plugged == 0) {
BlockDriver *drv = bs->drv;
if (drv && drv->bdrv_io_unplug) {
drv->bdrv_io_unplug(bs);
@ -2674,36 +2670,3 @@ void bdrv_io_unplug(BlockDriverState *bs)
bdrv_io_unplug(child->bs);
}
}
void bdrv_io_unplugged_begin(BlockDriverState *bs)
{
BdrvChild *child;
if (bs->io_plug_disabled++ == 0 && bs->io_plugged > 0) {
BlockDriver *drv = bs->drv;
if (drv && drv->bdrv_io_unplug) {
drv->bdrv_io_unplug(bs);
}
}
QLIST_FOREACH(child, &bs->children, next) {
bdrv_io_unplugged_begin(child->bs);
}
}
void bdrv_io_unplugged_end(BlockDriverState *bs)
{
BdrvChild *child;
assert(bs->io_plug_disabled);
QLIST_FOREACH(child, &bs->children, next) {
bdrv_io_unplugged_end(child->bs);
}
if (--bs->io_plug_disabled == 0 && bs->io_plugged > 0) {
BlockDriver *drv = bs->drv;
if (drv && drv->bdrv_io_plug) {
drv->bdrv_io_plug(bs);
}
}
}

2
include/block/block.h
View File

@ -526,8 +526,6 @@ int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
void bdrv_io_plug(BlockDriverState *bs);
void bdrv_io_unplug(BlockDriverState *bs);
void bdrv_io_unplugged_begin(BlockDriverState *bs);
void bdrv_io_unplugged_end(BlockDriverState *bs);
/**
* bdrv_drained_begin:

3
include/block/block_int.h
View File

@ -526,9 +526,8 @@ struct BlockDriverState {
uint64_t write_threshold_offset;
NotifierWithReturn write_threshold_notifier;
/* counters for nested bdrv_io_plug and bdrv_io_unplugged_begin */
/* counter for nested bdrv_io_plug */
unsigned io_plugged;
unsigned io_plug_disabled;
int quiesce_counter;
};