Commit c6c82e0c authored by Eric Farman's avatar Eric Farman Committed by Cornelia Huck
Browse files

vfio-ccw: Check initialized flag in cp_init() 



We have a really nice flag in the channel_program struct that
indicates if it had been initialized by cp_init(), and use it
as a guard in the other cp accessor routines, but not for a
duplicate call into cp_init(). The possibility of this occurring
is low, because that flow is protected by the private->io_mutex
and FSM CP_PROCESSING state. But then why bother checking it
in (for example) cp_prefetch() then?

Let's just be consistent and check for that in cp_init() too.

Fixes: 71189f26 ("vfio-ccw: make it safe to access channel programs")
Signed-off-by: default avatarEric Farman <farman@linux.ibm.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Acked-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Message-Id: <20210511195631.3995081-2-farman@linux.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent 6efb943b

drivers/s390/cio/vfio_ccw_cp.c

+4 −0
Original line number Diff line number Diff line
@@ -638,6 +638,10 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb) 
	static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 1);

	int ret;



	/* this is an error in the caller */

	if (cp->initialized)

		return -EBUSY;



	/*

	 * We only support prefetching the channel program. We assume all channel

	 * programs executed by supported guests likewise support prefetching.