Commit 42a65f02 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

block: Remove bdrv_set_aio_context() 



All callers of bdrv_set_aio_context() are eliminated now, they have
moved to bdrv_try_set_aio_context() and related safe functions. Remove
bdrv_set_aio_context().

With this, we can now know that the .set_aio_ctx callback must be
present in bdrv_set_aio_context_ignore() because
bdrv_can_set_aio_context() would have returned false previously, so
instead of checking the condition, we can assert it.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 26bf15e4

block.c

+14 −16
Original line number Diff line number Diff line
@@ -5789,8 +5789,17 @@ static void bdrv_attach_aio_context(BlockDriverState *bs, 
    bs->walking_aio_notifiers = false;

}



/* @ignore will accumulate all visited BdrvChild object. The caller is

 * responsible for freeing the list afterwards. */

/*

 * Changes the AioContext used for fd handlers, timers, and BHs by this

 * BlockDriverState and all its children and parents.

 *

 * The caller must own the AioContext lock for the old AioContext of bs, but it

 * must not own the AioContext lock for new_context (unless new_context is the

 * same as the current context of bs).

 *

 * @ignore will accumulate all visited BdrvChild object. The caller is

 * responsible for freeing the list afterwards.

 */

void bdrv_set_aio_context_ignore(BlockDriverState *bs,

                                 AioContext *new_context, GSList **ignore)

{
@@ -5813,11 +5822,10 @@ void bdrv_set_aio_context_ignore(BlockDriverState *bs, 
        if (g_slist_find(*ignore, child)) {

            continue;

        }

        if (child->role->set_aio_ctx) {

        assert(child->role->set_aio_ctx);

        *ignore = g_slist_prepend(*ignore, child);

        child->role->set_aio_ctx(child, new_context, ignore);

    }

    }



    bdrv_detach_aio_context(bs);
@@ -5830,16 +5838,6 @@ void bdrv_set_aio_context_ignore(BlockDriverState *bs, 
    aio_context_release(new_context);

}



/* The caller must own the AioContext lock for the old AioContext of bs, but it

 * must not own the AioContext lock for new_context (unless new_context is

 * the same as the current context of bs). */

void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)

{

    GSList *ignore_list = NULL;

    bdrv_set_aio_context_ignore(bs, new_context, &ignore_list);

    g_slist_free(ignore_list);

}



static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx,

                                            GSList **ignore, Error **errp)

{

docs/devel/multiple-iothreads.txt

+2 −2
Original line number Diff line number Diff line
@@ -109,7 +109,7 @@ The AioContext originates from the QEMU block layer, even though nowadays 
AioContext is a generic event loop that can be used by any QEMU subsystem.



The block layer has support for AioContext integrated.  Each BlockDriverState

is associated with an AioContext using bdrv_set_aio_context() and

is associated with an AioContext using bdrv_try_set_aio_context() and

bdrv_get_aio_context().  This allows block layer code to process I/O inside the

right AioContext.  Other subsystems may wish to follow a similar approach.
@@ -134,5 +134,5 @@ Long-running jobs (usually in the form of coroutines) are best scheduled in 
the BlockDriverState's AioContext to avoid the need to acquire/release around

each bdrv_*() call.  The functions bdrv_add/remove_aio_context_notifier,

or alternatively blk_add/remove_aio_context_notifier if you use BlockBackends,

can be used to get a notification whenever bdrv_set_aio_context() moves a

can be used to get a notification whenever bdrv_try_set_aio_context() moves a

BlockDriverState to a different AioContext.

include/block/block.h

+0 −9
Original line number Diff line number Diff line
@@ -583,15 +583,6 @@ AioContext *bdrv_get_aio_context(BlockDriverState *bs); 
 */

void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);



/**

 * bdrv_set_aio_context:

 *

 * Changes the #AioContext used for fd handlers, timers, and BHs by this

 * BlockDriverState and all its children.

 *

 * This function must be called with iothread lock held.

 */

void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);

void bdrv_set_aio_context_ignore(BlockDriverState *bs,

                                 AioContext *new_context, GSList **ignore);

int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,