Drivers that do not provide kernel verbs support should not be used by ib
kernel clients at all.

In case a device does not implement all mandatory verbs for kverbs usage
mark it as a non kverbs provider and prevent its usage for all clients
except for uverbs.

The device is marked as a non kverbs provider using the 'kverbs_provider'
flag which should only be set by the core code.  The clients can choose
whether kverbs are requested for its usage using the 'no_kverbs_req' flag
which is currently set for uverbs only.

This patch allows drivers to remove mandatory verbs stubs and simply set
the callbacks to NULL. The IB device will be registered as a non-kverbs
provider. Note that verbs that are required for the device registration
process must be implemented.
Signed-off-by: NGal Pressman <galpress@amazon.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

ib_umem_get() can only be called in a method callback, which always has a
udata parameter. This allows ib_umem_get() to derive the ucontext pointer
directly from the udata without requiring the drivers to find it in some
way or another.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NShamir Rabinovitch <shamir.rabinovitch@oracle.com>

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make all the required change to start use the ib_device_ops structure.
Signed-off-by: NKamal Heib <kamalheib1@gmail.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

All of the old arguments can be derived from the uverbs_attr_bundle
structure, so get rid of the redundant arguments. Most of the prior work
has been removing users of the arguments to allow this to be a simple
patch.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This creates a consistent way to access the two core buffers across write
and write_ex handlers.

Remove the open coded ucore conversion in the write/ex compatibility
handlers.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Now that we have metadata describing the command format the core code can
directly compute the udata pointers and all the really ugly
ib_uverbs_init_udata() calls can be removed from the handlers.

This means all the write() handlers are no longer sensitive to the layout
of the command buffer.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

The core code needs to compute the udata so we may as well pass it in the
uverbs_attr_bundle instead of on the stack. This converts the simple case
of write_ex() which already has a core calculation.

Also change the write() path to use the attrs for ib_uverbs_init_udata()
instead of on the stack. This lets the write to write_ex compatibility
path continue to follow the lead of the _ex path.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

The size meta-data in the prior patch describes the smallest acceptable
buffer for the write() interface. Globally check this in the core code.

This is necessary in the case of write() methods that have a driver udata
to prevent computing a negative udata buffer length.

The return code of -ENOSPC is chosen here as some of the handlers already
use this code, however many other handler use EINVAL.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

Currently they return the command length, while all other handlers return
0. This makes the write path closer to the write_ex and ioctl path.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

Now that we can add meta-data to the description of write() methods we
need to pass the uverbs_attr_bundle into all write based handlers so
future patches can use it as a container for any new data transferred out
of the core.

This is the first step to bringing the write() and ioctl() methods to a
common interface signature.

This is a simple search/replace, and we push the attr down into the uobj
and other APIs to keep changes minimal.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

This organizes the write commands into objects and links them to the
uverbs_api data structure. The command path is reworked to use uapi
instead of its internal structures.

The command mask is moved from a runtime check to a registration time
check in the uapi.

Since the write interface does not have the object ID as part of the
command, the radix bins are converted into linear lists to support the
lookup.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

We have many cases where parts of the uapi are not supported in a driver,
needs a certain protocol, or whatever. It is best to reflect this directly
into the struct uverbs_api when it is built so that everything is simply
blocked off, and future introspection can report a proper supported list.

This is done by adding some additional helpers to the definition list
language that disable objects based on a 'supported' call back, and a
helper that disables based on a NULL struct ib_device function pointer.

Disablement is global. For instance, if a driver disables an object then
everything connected to that object is removed, including core methods.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

The 'tree' data structure is very hard to build at compile time, and this
makes it very limited. The new radix tree based compiler can handle a more
complex input language that does not require the compiler to perfectly
group everything into a neat tree structure.

Instead use a simple list to describe to input, where the list elements
can be of various different 'opcodes' instructing the radix compiler what
to do. Start out with opcodes chaining to other definition lists and
chaining to the existing 'tree' definition.

Replace the very top level of the 'object tree' with this list type and
get rid of struct uverbs_object_tree_def and DECLARE_UVERBS_OBJECT_TREE.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

Replace custom code to allocate indexes to generic kernel API.
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

These return the same thing but dev_name is a more conventional use of the
kernel API.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Reviewed-by: NLeon Romanovsky <leonro@mellanox.com>
Reviewed-by: NDennis Dalessandro <dennis.dalessandro@intel.com>

To support disassociation and PCI hot unplug, we have to track all the
VMAs that refer to the device IO memory. When disassociation occurs the
VMAs have to be revised to point to the zero page, not the IO memory, to
allow the physical HW to be unplugged.

The three drivers supporting this implemented three different versions
of this algorithm, all leaving something to be desired. This new common
implementation has a few differences from the driver versions:

- Track all VMAs, including splitting/truncating/etc. Tie the lifetime of
  the private data allocation to the lifetime of the vma. This avoids any
  tricks with setting vm_ops which Linus didn't like. (see link)
- Support multiple mms, and support properly tracking mmaps triggered by
  processes other than the one first opening the uverbs fd. This makes
  fork behavior of disassociation enabled drivers the same as fork support
  in normal drivers.
- Don't use crazy get_task stuff.
- Simplify the approach for to racing between vm_ops close and
  disassociation, fixing the related bugs most of the driver
  implementations had. Since we are in core code the tracking list can be
  placed in struct ib_uverbs_ufile, which has a lifetime strictly longer
  than any VMAs created by mmap on the uverbs FD.

Link: https://www.spinics.net/lists/stable/msg248747.html
Link: https://lkml.kernel.org/r/CA+55aFxJTV_g46AQPoPXen-UPiqR1HGMZictt7VpC-SMFbm3Cw@mail.gmail.comSigned-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The error path has several mistakes

- cdev_del should not be called if cdev_device_add fails
- We must call put_device on all the goto exit paths as that is what frees
  the uapi, SRCU and the struct itself.

While we are here consolidate all the uvdev_dev init that cannot fail at
the top.

Fixes: c5c4d92e ("RDMA/uverbs: Use cdev_device_add() instead of cdev_add()")
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Reviewed-by: NParav Pandit <parav@mellanox.com>

This does nothing but indicate if the uverbs_file is in the device's list,
use list_del_init instead.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

Currently a uverbs completion event queue is flushed of events in
ib_uverbs_comp_event_close() with the queue spinlock held and then
released.  Yet setting ev_queue->is_closed is not set until later in
uverbs_hot_unplug_completion_event_file().

In between the time ib_uverbs_comp_event_close() releases the lock and
uverbs_hot_unplug_completion_event_file() acquires the lock, a completion
event can arrive and be inserted into the event queue by
ib_uverbs_comp_handler().

This can cause a "double add" list_add warning or crash depending on the
kernel configuration, or a memory leak because the event is never dequeued
since the queue is already closed down.

So add setting ev_queue->is_closed = 1 to ib_uverbs_comp_event_close().

Cc: stable@vger.kernel.org
Fixes: 1e7710f3 ("IB/core: Change completion channel to use the reworked objects schema")
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

Instead of explicitly adding device attribute files and handling such
error conditions, depend on device core layer to create device attributes
files based group pointer NULL terminated array.
Signed-off-by: NParav Pandit <parav@mellanox.com>
Reviewed-by: NDaniel Jurgens <danielj@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

Instead of doing two step process to add char device and create underlying
device, use cdev_device_add() which does both.

Currently a kobject per uverbs_device is created to keep reference to its
holding ib_uverbs_device in addition to its underlying device 'dev'.

Instead just use uverbs_device->dev to keep a reference to.

With this change there is single reference tracker for ib_uverbs_device
structure.

This allows for subsequent patch to registers group attribute as well
using single API cdev_device_add().
Signed-off-by: NParav Pandit <parav@mellanox.com>
Reviewed-by: NDaniel Jurgens <danielj@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

If ib_uverbs_create_uapi() fails, dev_num should be freed from the bitmap.

Fixes: 7d96c9b1 ("IB/uverbs: Have the core code create the uverbs_root_spec")
Signed-off-by: NParav Pandit <parav@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

Everything now uses the uverbs_uapi data structure.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

This radix tree datastructure is intended to replace the 'hash' structure
used today for parsing ioctl methods during system calls. This first
commit introduces the structure and builds it from the existing .rodata
descriptions.

The so-called hash arrangement is actually a 5 level open coded radix tree.
This new version uses a 3 level radix tree built using the radix tree
library.

Overall this is much less code and much easier to build as the radix tree
API allows for dynamic modification during the building. There is a small
memory penalty to pay for this, but since the radix tree is allocated on
a per device basis, a few kb of RAM seems immaterial considering the
gained simplicity.

The radix tree is similar to the existing tree, but also has a 'attr_bkey'
concept, which is a small value'd index for each method attribute. This is
used to simplify and improve performance of everything in the next
patches.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Reviewed-by: NLeon Romanovsky <leonro@mellanox.com>
Reviewed-by: NMichael J. Ruhl <michael.j.ruhl@intel.com>

There is no reason for drivers to do this, the core code should take of
everything. The drivers will provide their information from rodata to
describe their modifications to the core's base uapi specification.

The core uses this to build up the runtime uapi for each device.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Reviewed-by: NMichael J. Ruhl <michael.j.ruhl@intel.com>
Reviewed-by: NLeon Romanovsky <leonro@mellanox.com>

The disassociate function was broken by design because it failed all
commands. This prevents userspace from calling destroy on a uobject after
it has detected a device fatal error and thus reclaiming the resources in
userspace is prevented.

This fix is now straightforward, when anything destroys a uobject that is
not the user the object remains on the IDR with a NULL context and object
pointer. All lookup locking modes other than DESTROY will fail. When the
user ultimately calls the destroy function it is simply dropped from the
IDR while any related information is returned.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

Now that all the callbacks are safe to run concurrently with
disassociation this test can be eliminated. The ufile core infrastructure
becomes entirely self contained and is not sensitive to disassociation.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

This is a step to get rid of the global check for disassociation. In this
model, the ib_dev is not proven to be valid by the core code and cannot be
provided to the method. Instead, every method decides if it is able to
run after disassociation and obtains the ib_dev using one of three
different approaches:

- Call srcu_dereference on the udevice's ib_dev. As before, this means
  the method cannot be called after disassociation begins.
  (eg alloc ucontext)
- Retrieve the ib_dev from the ucontext, via ib_uverbs_get_ucontext()
- Retrieve the ib_dev from the uobject->object after checking
  under SRCU if disassociation has started (eg uobj_get)

Largely, the code is all ready for this, the main work is to provide a
ib_dev after calling uobj_alloc(). The few other places simply use
ib_uverbs_get_ucontext() to get the ib_dev.

This flexibility will let the next patches allow destroy to operate
after disassociation.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

We have a parallel unlocked reader and writer with ib_uverbs_get_context()
vs everything else, and nothing guarantees this works properly.

Audit and fix all of the places that access ucontext to use one of the
following locking schemes:
- Call ib_uverbs_get_ucontext() under SRCU and check for failure
- Access the ucontext through an struct ib_uobject context member
  while holding a READ or WRITE lock on the uobject.
  This value cannot be NULL and has no race.
- Hold the ucontext_lock and check for ufile->ucontext !NULL

This also re-implements ib_uverbs_get_ucontext() in a way that is safe
against concurrent ib_uverbs_get_context() and disassociation.

As a side effect, every access to ucontext in the commands is via
ib_uverbs_get_context() with an error check, or via the uobject, so there
is no longer any need for the core code to check ucontext on every command
call. These checks are also removed.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

The locking here has always been a bit crazy and spread out, upon some
careful analysis we can simplify things.

Create a single function uverbs_destroy_ufile_hw() that internally handles
all locking. This pulls together pieces of this process that were
sprinkled all over the places into one place, and covers them with one
lock.

This eliminates several duplicate/confusing locks and makes the control
flow in ib_uverbs_close() and ib_uverbs_free_hw_resources() extremely
simple.

Unfortunately we have to keep an extra mutex, ucontext_lock.  This lock is
logically part of the rwsem and provides the 'down write, fail if write
locked, wait if read locked' semantic we require.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

Rename 'cleanup_rwsem' to 'hw_destroy_rwsem' which is held across any call
to the type destroy function (aka 'hw' destroy). The main purpose of this
lock is to prevent normal add and destroy from running concurrently with
uverbs_cleanup_ufile()

Since the uobjects list is always manipulated under the 'hw_destroy_rwsem'
we can eliminate the uobjects_lock in the cleanup function. This allows
converting that lock to a very simple spinlock with a narrow critical
section.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

Now that ib_uobject has a ib_uverbs_file we don't need this extra one in
ib_ucq_object.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

The only purpose for this structure was to hold the ib_uobject_file
pointer, but now that is part of the standard ib_uobject the structure
no longer makes any sense, so get rid of it.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

Unnecessary clutter, to indirect through ucontext when the ufile would do.
Generally most of the code code should only be working with ufile, except
for a few places that touch the driver interface.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

The correct handle to refer to the idr/etc is ib_uverbs_file, revise all
the core APIs to use this instead. The user API are left as wrappers
that automatically convert a ucontext to a ufile for now.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

The IDR is part of the ib_ufile so all the machinery to lock it, handle
closing and disassociation rightly belongs to the ufile not the ucontext.

This changes the lifetime of that data to match the lifetime of the file
descriptor which is always strictly longer than the lifetime of the
ucontext.

We need the entire locking machinery to continue to exist after ucontext
destruction to allow us to return the destroy data after a device has been
disassociated.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

The specs are required to operate the uverbs file, so they belong inside
the ib_uverbs_device, not inside the ib_device. The spec passed in the
ib_device is just a communication from the driver and should not be used
during runtime.

This also changes the lifetime of the spec memory to match the
ib_uverbs_device, however at this time the spec_root can still contain
driver pointers after disassociation, so it cannot be used if ib_dev is
NULL. This is preparation for another series.
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Reviewed-by: NMichael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>

Drivers that use the IOCTL API may have the ib_uverbs_file and need a
way to get the related ib_ucontext from it, this is enabled by this
patch.

Downstream patches from this series will use it.
Signed-off-by: NYishai Hadas <yishaih@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

During disassociation the ucontext will become NULL, however due to how
the SRCU locking works the ucontext must only be examined after looking
at the ib_dev, which governs the RCU control flow.

With the wrong ordering userspace will see EINVAL instead of EIO for a
disassociated uverbs FD, which breaks rdma-core.

Cc: stable@vger.kernel.org
Fixes: 491d5c6a ("RDMA/uverbs: Move uncontext check before SRCU read lock")
Reported-by: NMark Bloch <markb@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Reviewed-by: NLeon Romanovsky <leonro@mellanox.com>