Commit 8f90b5e9 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Stefan Hajnoczi
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20161129113334.605-1-pbonzini@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 2ccede18

block/io.c

+2 −39
Original line number Diff line number Diff line
@@ -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);

        }

    }

}

include/block/block.h

+0 −2
Original line number Diff line number Diff line
@@ -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:

include/block/block_int.h

+1 −2
Original line number Diff line number Diff line
@@ -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;

};