From d79af7242bb237d00e40092810e6828fbb929d2d Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Thu, 10 Jan 2019 14:02:24 -0700 Subject: RDMA/device: Expose ib_device_try_get(() 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 Reviewed-by: Steve Wise Reviewed-by: Parav Pandit --- drivers/infiniband/core/device.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'drivers/infiniband/core/device.c') diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index 8872453e26c0..238ec42778ef 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -156,19 +156,26 @@ 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); return device; } +/** + * 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. + */ void ib_device_put(struct ib_device *device) { if (refcount_dec_and_test(&device->refcount)) complete(&device->unreg_completion); } +EXPORT_SYMBOL(ib_device_put); static struct ib_device *__ib_device_get_by_name(const char *name) { @@ -303,7 +310,6 @@ struct ib_device *ib_alloc_device(size_t size) rwlock_init(&device->client_data_lock); INIT_LIST_HEAD(&device->client_data_list); INIT_LIST_HEAD(&device->port_list); - refcount_set(&device->refcount, 1); init_completion(&device->unreg_completion); return device; @@ -620,6 +626,7 @@ int ib_register_device(struct ib_device *device, const char *name, goto cg_cleanup; } + refcount_set(&device->refcount, 1); device->reg_state = IB_DEV_REGISTERED; list_for_each_entry(client, &client_list, list) -- cgit v1.2.3-70-g09d2