struct ib_wc currently only includes the local QP number: this matches
the IB spec, but seems mostly useless. The following patch replaces
this with the pointer to qp itself, and updates all low level drivers
and all users.

This has the following advantages:
- Ability to get a per-qp context through wc->qp->qp_context
- Existing drivers already have the qp pointer ready in poll cq, so
  this change actually saves a tiny bit (extra memory read) on data path
  (for ehca it would actually be expensive to find the QP pointer when
  polling a CQ, but ehca does not support SRQ so we can leave wc->qp as
  NULL for ehca)
- Users that need the QP number can still get it through wc->qp->qp_num

Use case:

In IPoIB connected mode code, I have a common CQ shared by multiple
QPs.  To track connection usage, I need a way to get at some per-QP
context upon the completion, and I would like to avoid allocating
context object per work request just to stick a QP pointer into it.
With this code, I can just use wc->qp->qp_context.
Signed-off-by: NMichael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Return the sq_draining value back to user space for query_qp instead
of the en_sqd_async notify value, which is valid only for
modify_qp.  For query_qp, the draining status should returned.
Signed-off-by: NJack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Remove some trailing whitespace that has snuck in despite the best
efforts of whitespace=error-all.  Also fix a few other whitespace
bogosities.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Pass a struct ib_udata to the low-level driver's ->modify_srq() and
->modify_qp() methods, so that it can get to the device-specific data
passed in by the userspace driver.
Signed-off-by: NRalph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add a ib_uverbs_resize_cq_resp.driver_data field so that low-level
drivers can return data from a resize CQ operation to userspace.  Have
ib_uverbs_resize_cq() only copy the cqe field, to avoid having to bump
the userspace ABI.
Signed-off-by: NRalph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Lockdep warns when userspace creates a QP that uses different CQs for
send completions and receive completions, because both CQs are locked
and their mutexes belong to the same lock class.  However, we know
that the mutexes are distinct and the nesting is safe (there is no
possibility of AB-BA deadlock because the mutexes are locked with
down_read()), so annotate the situation with SINGLE_DEPTH_NESTING to
get rid of the lockdep warning.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

There were two functions that open-coded idr_read_cq() in terms of
idr_read_uobj() rather than using the helper.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Lockdep warns because uverbs is trying to take uobj->mutex when it
already holds that lock.  This is because there are really multiple
types of uobjs even though all of their locks are initialized in
common code.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

ib_uverbs_create_ah() and ib_uverbs_create_srq() did not release the
PD's read lock in their error paths, which lead to deadlock when
destroying the PD.
Signed-off-by: NMichael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Store away the user handle passed in from userspace when creating an
SRQ, so that the kernel can return the correct handle when an SRQ
asynchronous event occurs.  (A 0 was incorrectly stored as the user
handle as part of the changes in 9ead190b, "IB/uverbs: Don't serialize
with ib_uverbs_idr_mutex")
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

In ib_uverbs_post_send(), move the "out:" label after the loop that
frees the list of work requests, since the only place that jumps there
is before any work requests could possibly be added to the list.

This removes a compile warning: "is_ud might be used uninitialized in
this function".
Signed-off-by: NKrishna Kumar <krkumar2@in.ibm.com>
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>

Factor out common code for adding a userspace object to an idr into a
function idr_add_uobj().  This shrinks both the source and object code:

add/remove: 1/0 grow/shrink: 0/6 up/down: 57/-220 (-163)
function                                     old     new   delta
idr_add_uobj                                   -      57     +57
ib_uverbs_create_ah                          543     512     -31
ib_uverbs_create_srq                         662     630     -32
ib_uverbs_reg_mr                             737     699     -38
ib_uverbs_create_cq                          639     600     -39
ib_uverbs_alloc_pd                           485     446     -39
ib_uverbs_create_qp                         1020     979     -41
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

In error paths when destroying an object, uverbs should not decrement
associated objects' usecnt, since ib_dereg_mr(), ib_destroy_qp(),
etc. already do that.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

If ibdev->alloc_ucontext() fails then ib_uverbs_get_context() does not
unlock file->mutex before returning error.

Signed-off by: Ganapathi CH <cganapathi@novell.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

The old code incorrectly used the primary P_Key index as the alternate
index too.
Signed-off-by: NAmi Perlmutter <amip@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

The old code didn't convert from the kernel's enum correctly.
Signed-off-by: NDotan Barak <dotanb@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Pass actual capacity of created SRQ back to userspace, so that
userspace can report accurate capacities.  This requires an ABI bump,
to change struct ib_uverbs_create_srq_resp.
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 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>

Remove trailing whitespace and fix indentation that with spaces
instead of tabs.
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>

Add a node_guid field to struct ib_device.  It is the responsibility
of the low-level driver to initialize this field before registering a
device with the midlayer.  Convert everyone to looking at this field
instead of calling ib_query_device() when all they want is the node
GUID, and remove the node_guid field from struct ib_device_attr.
Signed-off-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

ib_uverbs_create_cq() should release the completion channel event file
if an error occurs after it looks it up.  Also, if userspace asks for
a completion channel and we don't find it, an error should be returned
instead of silently creating a CQ without a completion channel.
Signed-off-by: NJack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

AH attribute's ah_flags need to be set according to the is_global flag
passed in from userspace.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

If an operation fails after incrementing an object's reference count,
then it should decrement the reference count on the error path.
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>

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>

Move the computation of QP capabilities (max scatter/gather entries,
max inline data, etc) into the kernel, and have the uverbs module
return the values as part of the create QP response.  This keeps
precise knowledge of device limits in the low-level kernel driver.

This requires an ABI bump, so while we're making changes, get rid of
the max_sge parameter for the modify SRQ command -- it's not used and
shouldn't be there.
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>

Reject userspace memory registrations with invalid permission flags:
"local write" is required if "remote write" or "remote atomic" is also
requested.

Pointed out by Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

By waiting to add resources to our lists until after the last
operation that can fail, we don't have to remove them from their lists
in the error path.  Also, we should hold the idr mutex until we know
whether resource creation has succeed or failed, to avoid someone
finding a resource in our table before we're ready.

Loosely based on work by Robert Walsh <rjwalsh@pathscale.com>.
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>

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>

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>