Clarify that bus_dma does not stall future load requests once a load is

deferred.  The caller is required to enforce that if that is desired.

MFC after:	2 weeks
This commit is contained in:
jhb 2012-08-30 14:44:30 +00:00
parent 165d5550eb
commit 5e14e64f45

View File

@ -580,8 +580,13 @@ The status of the mapping has been delivered to the callback.
The mapping has been deferred for lack of resources.
The callback will be called as soon as resources are available.
Callbacks are serviced in FIFO order.
To ensure that ordering is guaranteed, all subsequent load requests will also
be deferred until all callbacks have been processed.
.Pp
Note that subsequent load operations for the same tag that do not require
extra resources will still succeed.
This may result in out-of-order processing of requests.
If the caller requires the order of requests to be preserved,
then the caller is required to stall subsequent requests until a pending
request's callback is invoked.
.It Er ENOMEM
The load request has failed due to insufficient resources, and the caller
specifically used the