diff options
| -rw-r--r-- | hw/scsi/scsi-bus.c | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c index 0a2eb11..2303130 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -120,17 +120,13 @@ static void scsi_device_for_each_req_async_bh(void *opaque) SCSIRequest *next; /* - * If the AioContext changed before this BH was called then reschedule into - * the new AioContext before accessing ->requests. This can happen when - * scsi_device_for_each_req_async() is called and then the AioContext is - * changed before BHs are run. + * The BB cannot have changed contexts between this BH being scheduled and + * now: BBs' AioContexts, when they have a node attached, can only be + * changed via bdrv_try_change_aio_context(), in a drained section. While + * we have the in-flight counter incremented, that drain must block. */ ctx = blk_get_aio_context(s->conf.blk); - if (ctx != qemu_get_current_aio_context()) { - aio_bh_schedule_oneshot(ctx, scsi_device_for_each_req_async_bh, - g_steal_pointer(&data)); - return; - } + assert(ctx == qemu_get_current_aio_context()); QTAILQ_FOREACH_SAFE(req, &s->requests, next, next) { data->fn(req, data->fn_opaque); @@ -138,11 +134,16 @@ static void scsi_device_for_each_req_async_bh(void *opaque) /* Drop the reference taken by scsi_device_for_each_req_async() */ object_unref(OBJECT(s)); + + /* Paired with blk_inc_in_flight() in scsi_device_for_each_req_async() */ + blk_dec_in_flight(s->conf.blk); } /* * Schedule @fn() to be invoked for each enqueued request in device @s. @fn() * runs in the AioContext that is executing the request. + * Keeps the BlockBackend's in-flight counter incremented until everything is + * done, so draining it will settle all scheduled @fn() calls. */ static void scsi_device_for_each_req_async(SCSIDevice *s, void (*fn)(SCSIRequest *, void *), @@ -163,6 +164,8 @@ static void scsi_device_for_each_req_async(SCSIDevice *s, */ object_ref(OBJECT(s)); + /* Paired with blk_dec_in_flight() in scsi_device_for_each_req_async_bh() */ + blk_inc_in_flight(s->conf.blk); aio_bh_schedule_oneshot(blk_get_aio_context(s->conf.blk), scsi_device_for_each_req_async_bh, data); @@ -1728,11 +1731,20 @@ static void scsi_device_purge_one_req(SCSIRequest *req, void *opaque) scsi_req_cancel_async(req, NULL); } +/** + * Cancel all requests, and block until they are deleted. + */ void scsi_device_purge_requests(SCSIDevice *sdev, SCSISense sense) { scsi_device_for_each_req_async(sdev, scsi_device_purge_one_req, NULL); + /* + * Await all the scsi_device_purge_one_req() calls scheduled by + * scsi_device_for_each_req_async(), and all I/O requests that were + * cancelled this way, but may still take a bit of time to settle. + */ blk_drain(sdev->conf.blk); + scsi_device_set_ua(sdev, sense); } |