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  1. 20 Feb, 2019 8 commits
    • Parvi Kaustubhi's avatar
      IB/usnic: Fix deadlock · 5bb3c1e9
      Parvi Kaustubhi authored 
      There is a dead lock in usnic ib_register and netdev_notify path.

	usnic_ib_discover_pf()
	| mutex_lock(&usnic_ib_ibdev_list_lock);
	 | usnic_ib_device_add();
	  | ib_register_device()
	   | usnic_ib_query_port()
	    | mutex_lock(&us_ibdev->usdev_lock);
	     | ib_get_eth_speed()
	      | rtnl_lock()

order of lock: &usnic_ib_ibdev_list_lock -> usdev_lock -> rtnl_lock

	rtnl_lock()
	 | usnic_ib_netdevice_event()
	  | mutex_lock(&usnic_ib_ibdev_list_lock);

order of lock: rtnl_lock -> &usnic_ib_ibdev_list_lock

Solution is to use the core's lock-free ib_device_get_by_netdev() scheme
to lookup ib_dev while handling netdev & inet events.
Signed-off-by: default avatarParvi Kaustubhi <pkaustub@cisco.com>
Reviewed-by: default avatarGovindarajulu Varadarajan <gvaradar@cisco.com>
Reviewed-by: default avatarTanmay Inamdar <tinamdar@cisco.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
      5bb3c1e9
    • Jason Gunthorpe's avatar
      RDMA/rxe: Close a race after ib_register_device · ca22354b
      Jason Gunthorpe authored 
      Since rxe allows unregistration from other threads the rxe pointer can
become invalid any moment after ib_register_driver returns. This could
cause a user triggered use after free.

Add another driver callback to be called right after the device becomes
registered to complete any device setup required post-registration.  This
callback has enough core locking to prevent the device from becoming
unregistered.
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
      ca22354b
    • Jason Gunthorpe's avatar
      RDMA/rxe: Add ib_device_get_by_name() and use it in rxe · 6cc2c8e5
      Jason Gunthorpe authored 
      rxe has an open coded version of this that is not as safe as the core
version. This lets us eliminate the internal device list entirely from
rxe.
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
      6cc2c8e5
    • Jason Gunthorpe's avatar
      RDMA/rxe: Use driver_unregister and new unregistration API · c367074b
      Jason Gunthorpe authored 
      rxe does not have correct locking for its registration/unregistration
paths, use the core code to handle it instead. In this mode
ib_unregister_device will also do the dealloc, so rxe is required to do
clean up from a callback.

The core code ensures that unregistration is done only once, and generally
takes care of locking and concurrency problems for rxe.
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
      c367074b
    • Jason Gunthorpe's avatar
      RDMA/device: Provide APIs from the core code to help unregistration · d0899892
      Jason Gunthorpe authored 
      These APIs are intended to support drivers that exist outside the usual
driver core probe()/remove() callbacks. Normally the driver core will
prevent remove() from running concurrently with probe(), once this safety
is lost drivers need more support to get the locking and lifetimes right.

ib_unregister_driver() is intended to be used during module_exit of a
driver using these APIs. It unregisters all the associated ib_devices.

ib_unregister_device_and_put() is to be used by a driver-specific removal
function (ie removal by name, removal from a netdev notifier, removal from
netlink)

ib_unregister_queued() is to be used from netdev notifier chains where
RTNL is held.

The locking is tricky here since once things become async it is possible
to race unregister with registration. This is largely solved by relying on
the registration refcount, unregistration will only ever work on something
that has a positive registration refcount - and then an unregistration
mutex serializes all competing unregistrations of the same device.
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
      d0899892
    • Jason Gunthorpe's avatar
      RDMA/rxe: Use ib_device_get_by_netdev() instead of open coding · 4c173f59
      Jason Gunthorpe authored 
      The core API handles the locking correctly and is faster if there are
multiple devices.
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
      4c173f59
    • Jason Gunthorpe's avatar
      RDMA/device: Add ib_device_get_by_netdev() · 324e227e
      Jason Gunthorpe authored 
      Several drivers need to find the ib_device from a given netdev. rxe needs
this at speed in an unsleepable context, so choose to implement the
translation using a RCU safe hash table.

The hash table can have a many to one mapping. This is intended to support
some future case where multiple IB drivers (ie iWarp and RoCE) connect to
the same netdevs. driver_ids will need to be different to support this.

In the process this makes the struct ib_device and ib_port_data RCU safe
by deferring their kfrees.
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
      324e227e
    • Jason Gunthorpe's avatar
      RDMA/device: Add ib_device_set_netdev() as an alternative to get_netdev · c2261dd7
      Jason Gunthorpe authored 
      The associated netdev should not actually be very dynamic, so for most
drivers there is no reason for a callback like this. Provide an API to
inform the core code about the net dev affiliation and use a core
maintained data structure instead.

This allows the core code to be more aware of the ndev relationship which
will allow some new APIs based around this.

This also uses locking that makes some kind of sense, many drivers had a
confusing RCU lock, or missing locking which isn't right.
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
      c2261dd7
  3. 19 Feb, 2019 13 commits
  5. 16 Feb, 2019 5 commits
  7. 15 Feb, 2019 5 commits
  9. 14 Feb, 2019 7 commits
  11. 13 Feb, 2019 2 commits
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