On Tue, Jan 15, 2019 at 09:53:49PM +0000, Parav Pandit wrote:
>
>
> > From: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
> >
> > It turns out future patches need this capability quite widely now, not just for
> > netlink, so provide two global functions to manage the registration lock
> > refcount.
> >
> > This also moves the point the lock becomes 1 to within ib_register_device()
> > so that the semantics of the public API are very sane and clear. Calling
> > ib_device_try_get() will fail on devices that are only allocated but not yet
> > registered.
> >
> > Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
> > drivers/infiniband/core/core_priv.h | 1 -
> > drivers/infiniband/core/device.c | 6 +++---
> > include/rdma/ib_verbs.h | 24 ++++++++++++++++++++++--
> > 3 files changed, 25 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/infiniband/core/core_priv.h
> > b/drivers/infiniband/core/core_priv.h
> > index 3cd830d52967eb..616734313f0c69 100644
> > +++ b/drivers/infiniband/core/core_priv.h
> > @@ -267,7 +267,6 @@ static inline int ib_mad_enforce_security(struct
> > ib_mad_agent_private *map, #endif
> >
> > struct ib_device *ib_device_get_by_index(u32 ifindex); -void
> > ib_device_put(struct ib_device *device);
> > /* RDMA device netlink */
> > void nldev_init(void);
> > void nldev_exit(void);
> > diff --git a/drivers/infiniband/core/device.c
> > b/drivers/infiniband/core/device.c
> > index 8872453e26c07c..9b5c72d3c85a88 100644
> > +++ b/drivers/infiniband/core/device.c
> > @@ -156,8 +156,7 @@ struct ib_device *ib_device_get_by_index(u32 index)
> > down_read(&lists_rwsem);
> > device = __ib_device_get_by_index(index);
> > if (device) {
> > - /* Do not return a device if unregistration has started. */
> > - if (!refcount_inc_not_zero(&device->refcount))
> > + if (!ib_device_try_get(device))
> > device = NULL;
> > }
> > up_read(&lists_rwsem);
> > @@ -169,6 +168,7 @@ void ib_device_put(struct ib_device *device)
>
> Please add below hunk comment block for exported symbol.
>
> +/**
> + * ib_device_put - Release IB device reference
> + * @device: device whose reference to be released
> + *
> + * ib_device_put() releases reference to the IB device to allow
> + * it to be unregistered and eventually free.
> + */
Okay, did both. I'll send a V2 when Moni settles if advise_mr needs
this patch in -rc or not..
Thanks,
Jason
