Export ib_umem_get()/ib_umem_release() and put low-level drivers in
control of when to call ib_umem_get() to pin and DMA map userspace,
rather than always calling it in ib_uverbs_reg_mr() before calling the
low-level driver's reg_user_mr method.

Also move these functions to be in the ib_core module instead of
ib_uverbs, so that driver modules using them do not depend on
ib_uverbs.

This has a number of advantages:
 - It is better design from the standpoint of making generic code a
   library that can be used or overridden by device-specific code as
   the details of specific devices dictate.
 - Drivers that do not need to pin userspace memory regions do not
   need to take the performance hit of calling ib_mem_get().  For
   example, although I have not tried to implement it in this patch,
   the ipath driver should be able to avoid pinning memory and just
   use copy_{to,from}_user() to access userspace memory regions.
 - Buffers that need special mapping treatment can be identified by
   the low-level driver.  For example, it may be possible to solve
   some Altix-specific memory ordering issues with mthca CQs in
   userspace by mapping CQ buffers with extra flags.
 - Drivers that need to pin and DMA map userspace memory for things
   other than memory regions can use ib_umem_get() directly, instead
   of hacks using extra parameters to their reg_phys_mr method.  For
   example, the mlx4 driver that is pending being merged needs to pin
   and DMA map QP and CQ buffers, but it does not need to create a
   memory key for these buffers.  So the cleanest solution is for mlx4
   to call ib_umem_get() in the create_qp and create_cq methods.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Wait until all users have closed their device context before allowing
device unregistration to complete.  This prevents a crash caused by
referring to stale data structures.

A better solution would be to have a way to revoke contexts rather
than waiting for userspace to close the context, but that's a much
bigger change that will have to wait.  For now let's at least avoid
the crash.
Signed-off-by: NJack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: NMichael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Currently, all userspace verbs operations that call into the kernel
are serialized by ib_uverbs_idr_mutex.  This can be a scalability
issue for some workloads, especially for devices driven by the ipath
driver, which needs to call into the kernel even for datapath
operations.

Fix this by adding reference counts to the userspace objects, and then
converting ib_uverbs_idr_mutex into a spinlock that only protects the
idrs long enough to take a reference on the object being looked up.
Because remove operations may fail, we have to do a slightly funky
two-step deletion, which is described in the comments at the top of
uverbs_cmd.c.

This also still leaves ib_uverbs_idr_lock as a single lock that is
possibly subject to contention.  However, the lock hold time will only
be a single idr operation, so multiple threads should still be able to
make progress, even if ib_uverbs_idr_lock is being ping-ponged.

Surprisingly, these changes even shrink the object code:

add/remove: 23/5 grow/shrink: 4/21 up/down: 633/-693 (-60)
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add support to uverbs to handle querying userspace SRQs (shared
receive queues), including adding an ABI for marshalling requests and
responses.  The kernel midlayer already has the underlying
ib_query_srq() function.
Signed-off-by: NDotan Barak <dotanb@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add support to uverbs to handle querying userspace QPs (queue pairs),
including adding an ABI for marshalling requests and responses.  The
kernel midlayer already has the underlying ib_query_qp() function.
Signed-off-by: NDotan Barak <dotanb@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add support to uverbs to handle resizing userspace CQs (completion
queues), including adding an ABI for marshalling requests and
responses.  The kernel midlayer already has ib_resize_cq().
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

semaphore to mutex conversion by Ingo and Arjan's script.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
[ Sanity-checked on real IB hardware ]
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

uverbs needs to track which multicast groups is each qp
attached to, in order to properly detach when cleanup
is performed on device file close.
Signed-off-by: NJack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: NMichael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Userspace CQs that have no completion event channel attached end up
with their cq_context set to NULL.  However, asynchronous events like
"CQ overrun" can still occur on such CQs, so add a uverbs_file member
to struct ib_ucq_object that we can follow to deliver these events.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Move ib_uverbs module to using cdev_alloc() and class_device_create()
so that we can handle device lifetime properly.  Now we can make sure
we keep all of our data structures around until the last way to reach
them is gone.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add kernel support for userspace calling poll CQ, request CQ
notification, post send, post receive, post SRQ receive, create AH and
destroy AH commands.  These commands allow us to support userspace
verbs for devices that can't perform these operations directly from
userspace (eg the PathScale HCA).
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Introduce new userspace verbs ABI version 3.  This eliminates some
unneeded commands, and adds support for user-created completion
channels.  This cleans up problems with file leaks on error paths, and
also makes sure that file descriptors are always installed into the
correct process.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Al Viro pointed out that the current IB userspace verbs interface
allows userspace to cause mischief by closing file descriptors before
we're ready, or issuing the same command twice at the same time.  This
patch closes those races, and fixes other obvious problems such as a
module reference leak.

Some other interface bogosities will require an ABI change to fix
properly, so I'm deferring those fixes until 2.6.15.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

completion events after destroying a CQ, QP or SRQ.  We do this by
sweeping the event lists before returning from a destroy calls, and
then return the number of events already reported before the destroy
call.  This allows userspace wait until it has processed all events
for an object returned from the kernel before it frees its context for
the object.

The ABI of the destroy CQ, destroy QP and destroy SRQ commands has to
change to return the event count, so bump the ABI version from 1 to 2.
The userspace libibverbs library has already been updated to handle
both the old and new ABI versions.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Move the InfiniBand headers from drivers/infiniband/include to include/rdma.
This allows InfiniBand-using code to live elsewhere, and lets us remove the
ugly EXTRA_CFLAGS include path from the InfiniBand Makefiles.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add SRQ support to userspace verbs module.  This adds several commands
and associated structures, but it's OK to do this without bumping the
ABI version because the commands are added at the end of the list so
they don't change the existing numbering.  There are two cases to
worry about:

1. New kernel, old userspace.  This is OK because old userspace simply
   won't try to use the new SRQ commands.  None of the old commands are
   changed.

2. Old kernel, new userspace.  This works perfectly as long as
   userspace doesn't try to use SRQ commands.  If userspace tries to
   use SRQ commands, it will get EINVAL, which is perfectly
   reasonable: the kernel doesn't support SRQs, so we couldn't do any
   better.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Make some lawyers happy and add copyright notices for people who
forgot to include them when they actually touched the code.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add support for O_ASYNC notifications on userspace verbs
completion and asynchronous event file descriptors.
Signed-off-by: NGleb Natapov <glebn@voltaire.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add the core of the InfiniBand userspace verbs implementation, including
creating character device nodes, dispatching requests from userspace, and
passing event notifications back up to userspace.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>