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| author |   Eric Farman <farman@linux.ibm.com> | 2021-05-11 21:56:29 +0200 |
|---|---|---|
| committer |   Cornelia Huck <cohuck@redhat.com> | 2021-05-12 12:59:50 +0200 |
| commit | c6c82e0cd8125d30f2f1b29205c7e1a2f1a6785b (patch) | |
| tree | c2a1ef68f6f2d6d427d0c798c1ec711fe6a34412 /drivers/s390/cio/vfio_ccw_cp.c | |
| parent | Linux 5.13-rc1 (diff) | |
| download | linux-dev-c6c82e0cd8125d30f2f1b29205c7e1a2f1a6785b.tar.xz linux-dev-c6c82e0cd8125d30f2f1b29205c7e1a2f1a6785b.zip | |
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: 71189f263f8a3 ("vfio-ccw: make it safe to access channel programs")
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Matthew Rosato <mjrosato@linux.ibm.com>
Message-Id: <20210511195631.3995081-2-farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Diffstat (limited to 'drivers/s390/cio/vfio_ccw_cp.c')
| -rw-r--r-- | drivers/s390/cio/vfio_ccw_cp.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index b9febc581b1f..8d1b2771c1aa 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -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. |