Commit Graph

709232 Commits

Author SHA1 Message Date
Ben Skeggs
d52ddc953e drm/nouveau/imem: separate suspend/resume backup handling into their own functions
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:19 +10:00
Ben Skeggs
71370e620a drm/nouveau/imem: remove now-unused wrapper for backend objects
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:19 +10:00
Ben Skeggs
03edf1b31a drm/nouveau/imem/nv50: support eviction of BAR2 mappings
A good deal of the structures we map into here aren't accessed very often
at all, and Fedora 26 has exposed an issue where after creating a heap of
channels, BAR2 space would run out, and we'd need to make use of the slow
path while accessing important structures like page tables.

This implements an LRU on BAR2 space, which allows eviction of mappings
that aren't currently needed, to make space for other objects.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:19 +10:00
Ben Skeggs
69b136f200 drm/nouveau/imem/nv50: prevent fast-path for mapped objects when BAR isn't ready
Another piece of solving the "GP100 BAR2 VMM bootstrap" puzzle.

Without doing this, we'd attempt to write PDEs for the lower page table
levels through BAR2 before BAR2 access has been fully initialised.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:19 +10:00
Ben Skeggs
dfcbd55068 drm/nouveau/imem/nv50: map bar2 write-combined
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:19 +10:00
Ben Skeggs
be55287aa5 drm/nouveau/imem/nv50: embed nvkm_instobj directly into nv04_instobj
This is not as simple as it was for earlier GPUs, due to the need to swap
accessor functions depending on whether BAR2 is usable or not.

We were previously protected by nvkm_instobj's accessor functions keeping
an object mapped permanently, with some unclear magic that managed to hit
the slow-path where needed even if an object was marked as mapped.

That's been replaced here by reference counting maps (some objects, like
page tables can be accessed concurrently), and swapping the functions as
necessary.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:19 +10:00
Ben Skeggs
af515ec8d3 drm/nouveau/imem/nv50: move slow-path locking into rd/wr functions
This is to simplify upcoming changes.  The slow-path is something that
currently occurs during bootstrap of the BAR2 VMM, while backing up an
object during suspend/resume, or when BAR2 address space runs out.

The latter is a real problem that can happen at runtime, and occurs in
Fedora 26 already (due to some change that causes a lot of channels to
be created at login), so ideally we'd prefer not to make it any slower.

We'd also like suspend/resume speed to not suffer.

Upcoming commits will solve those problems in a better way, making the
extra overhead of moving the locking here a non-issue.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:19 +10:00
Ben Skeggs
f584bde609 drm/nouveau/imem/nv50: split object map out from api functions
acquire()/boot() will need different logic in addition to performing
the actual mapping.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:19 +10:00
Ben Skeggs
b807270cbd drm/nouveau/imem/nv40: map bar2 write-combined
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:19 +10:00
Ben Skeggs
62465ac518 drm/nouveau/imem/nv40: embed nvkm_instobj directly into nv04_instobj
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
87717e7f28 drm/nouveau/imem/nv04: directly embed nvkm_instobj into nv04_instobj
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
49814f62a2 drm/nouveau/imem: allow nvkm_instobj to be directly embedded in backend object
This will eliminate a step through the call chain, and give backends
more flexibility.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
07bbc1c5f4 drm/nouveau/core/memory: split info pointers from accessor pointers
The accessor functions can change as a result of acquire()/release() calls,
and are protected by any refcounting done there.

Other functions must remain constant, as they can be called any time.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
dde59b9c34 drm/nouveau/imem: add some useful debug output
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
70433b904a drm/nouveau/bar/gm107-: wait for instance block binding to complete
Discovered by accident while working to use BAR2 access to instmem objects
on more paths.

We've apparently been relying on luck up until now!

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
8e644cb29c drm/nouveau/bar: initialise bar2 during oneinit
If we initialise BAR2 earlier, we're able to complete BAR1 setup using
the instmem fast-path.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
bb7e501a66 drm/nouveau/bar: prevent BAR2 mapping of objects during destructor
GP100's page table nests a lot more deeply than the GF100-compatible
layout we're currently using, which means our hackish-but-simple way
of dealing with BAR2 VMM teardown won't work anymore.

In order to sanely handle the chicken-and-egg (BAR2's PTs get mapped
into themselves) problem, we need prevent page tables getting mapped
back into BAR2 during the destruction of its VMM.

To do this, we simply key off the state that's now maintained by the
BAR2 init/fini functions.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
a78dbce9a1 drm/nouveau/bar: modify interface to bar2 vmm mapping
Match API with the BAR1 version.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
570889dc50 drm/nouveau/bar: modify interface to bar1 vmm mapping
Upcoming changes will remove the nvkm_vmm pointer from nvkm_vma, instead
requiring it to be explicitly specified on each operation.

It's not currently possible to get this information for BAR1 mappings,
so let's fix that ahead of time.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
e988952eef drm/nouveau/bar: expose interface to bar2 teardown
Will prevent spurious MMU fault interrupts if something decides to touch
BAR1 after we've unloaded the driver.

Exposed external to BAR so that INSTMEM can use it to better control the
suspend/resume fast-path access.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
48fe02478a drm/nouveau/bar: expose interface to bar2 initialisation
If we want to be able to hit the instmem fast-path in a few trickier cases,
we need to be more flexible with when we can initialise BAR2 access.

There's probably a decent case to be made for merging BAR/INSTMEM into BUS,
but that's something to ponder another day.

Flushes have been added after the write to bind the instance block,
as later commits will reveal the need for them.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
bbb163e189 drm/nouveau/bar: implement bar1 teardown
Will prevent spurious MMU fault interrupts if something decides to touch
BAR1 after we've unloaded the driver.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:18 +10:00
Ben Skeggs
7313cfa4f6 drm/nouveau/bar: move bar1 initialisation into its own function
BAR2 being done for practical reasons, this is just for consistency.

Flushes have been added after the write to bind the instance block,
as later commits will reveal the need for them.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:17 +10:00
Ben Skeggs
269fe32d33 drm/nouveau/bar: swap oneinit/init ordering, and rename bar3 to bar2
NVIDIA call it BAR2, Linux APIs treat it as BAR3 due to BAR1 being a
64-bit BAR, which I presume take two slots or something.

No actual code changes here, just to make future commits less messy.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:17 +10:00
Ben Skeggs
c9e7059296 drm/nouveau/bar: remove NV_PMC_ENABLE_PFIFO twiddling
It's handled by FIFO preinit() now.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:17 +10:00
Ben Skeggs
e69dae85c9 drm/nouveau/bar/nv50,g84: drop mmu invalidate
Will already be done by MMU as a result of the PT writes that occur
during BAR2 bootstrapping.

This is likely just a left-over from the days when it was hardcoded.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:17 +10:00
Ben Skeggs
5e721ad198 drm/nouveau/fifo: perform reset from preinit
RM appears to do this really early in its initialisation, before DEVINIT.

We currently do this before BAR2 initialisation for some reason.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:17 +10:00
Ben Skeggs
b5078d731f drm/nouveau/disp: add missing newline in ior debug messages
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:17 +10:00
Ben Skeggs
12973a37c4 drm/nouveau/secboot: add missing newline in debug message
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:17 +10:00
Ben Skeggs
4246b92cf9 drm/nouveau/core/device: remove object include to prevent unnecessary rebuilds
nvkm_device hasn't subclassed nvkm_object in a long time.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:16 +10:00
Ben Skeggs
82be74ee3b drm/nouveau/core/subdev: compile out messages for unwanted debug levels
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:16 +10:00
Ben Skeggs
153b642fcb drm/nouveau/core/gpuobj: remove embedded struct nvkm_object
nvkm_gpuobj hasn't subclassed nvkm_object in a long time.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:16 +10:00
Ben Skeggs
8e0042d505 drm/nouveau/core/object: plumb the unmap ioctl through
MMU will be using this for BAR mappings.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:16 +10:00
Ben Skeggs
0132605039 drm/nouveau/core/object: allow arguments to be passed to map function
MMU will be needing this to specify kind info on BAR mappings.

We have no userspace currently using these interfaces, so break the ABI
instead of supporting both.  NVIF version bump so any future use can be
guarded.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:16 +10:00
Ben Skeggs
1f474be9a8 drm/nouveau/core/object: separate oclass data out into its own header
Want to be able to include this from core/device.h without pulling in
core/object.h.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:16 +10:00
Ben Skeggs
bbb10e6398 drm/nouveau: fix handling of GART OOM on pre-NV50 chipsets
The correct thing to do on OOM is to return 0 and set mm_node to NULL,
otherwise TTM will assume some other kind of error, and not attempt to
evict other buffers to make space.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:16 +10:00
Ben Skeggs
9551efcf76 drm/nouveau/kms/nv50: prevent oops in failure paths
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:15 +10:00
Ilia Mirkin
3a0bc8cb9b drm/nouveau/kms: add 8.1Gbps DP link rate
This was already done in dcb.c inside nvkm, but the other parser did not
get the update.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:15 +10:00
Jérémy Lefaure
73cef6cee7 drm/nouveau/bios/init: use ARRAY_SIZE
Using the ARRAY_SIZE macro improves the readability of the code. Also,
it is useless to re-invent it.

Found with Coccinelle with the following semantic patch:
@r depends on (org || report)@
type T;
T[] E;
position p;
@@
(
 (sizeof(E)@p /sizeof(*E))
|
 (sizeof(E)@p /sizeof(E[...]))
|
 (sizeof(E)@p /sizeof(T))
)

Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:15 +10:00
Ben Skeggs
f5a5b5232b remove some useless semicolons
Reported-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:15 +10:00
Rhys Kidd
451b58d2d0 drm/nouveau: Document nouveau support for Tegra in DRIVER_DESC
nouveau supports the Tegra K1 and higher after the SoC-based GPUs converged
with the main GeForce GPU families.

v2:
- Qualify that support is Tegra K1+ (Martin Peres)

Signed-off-by: Rhys Kidd <rhyskidd@gmail.com>
Reviewed-by: Martin Peres <martin.peres@free.fr>
Acked-by: Pierre Moreau <pierre.morrow@free.fr>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:15 +10:00
Rhys Kidd
d326563738 drm/nouveau/therm/gp100: initial implementation of new gp1xx temperature sensor
v2:
 - add nv138 and drop nv13b chipsets (Ilia Mirkin)
 - refactor out status variable and instead mask tsensor (Ilia Mirkin)
 - switch SHADOWed state message away from nvkm_error() (Ilia Mirkin)
 - rename internal temperature variable (Karol Herbst)

v3:
 - use nvkm_trace() for SHADOWed state message (Ben Skeggs)

Signed-off-by: Rhys Kidd <rhyskidd@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2017-11-02 13:32:15 +10:00
Dave Airlie
7a88cbd8d6 Linux 4.14-rc7
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Backmerge tag 'v4.14-rc7' into drm-next

Linux 4.14-rc7

Requested by Ben Skeggs for nouveau to avoid major conflicts,
and things were getting a bit conflicty already, esp around amdgpu
reverts.
2017-11-02 12:40:41 +10:00
Dave Airlie
0a4334c9e5 Merge tag 'drm-hisilicon-next-2017-11-01' of github.com:xin3liang/linux into drm-next
For 4.15

* tag 'drm-hisilicon-next-2017-11-01' of github.com:xin3liang/linux:
  drm/hisilicon: Ensure LDI regs are properly configured.
2017-11-02 11:36:55 +10:00
Dave Airlie
87331c8379 Merge tag 'drm-msm-next-2017-11-01' of git://people.freedesktop.org/~robclark/linux into drm-next
+ preemption support for a5xx[1][2]

 + display fixes for 8x96 (snapdragon 820) including fixes for 4k scanout
   (hwpipe assignment re-work to handle multiple hwpipe assigned to plane
   for wide scanout)

 + async cursor plane updates and fixes

 + refactor adreno_bind/hwinit.. still defer fw loading until device open,
   but move clk/irq/etc to probe/bind time to fix issues when fw isn't
   present in filesys

 + clk/dt bindings cleanups w/ backward compat via msm_clk_get() (dt docs
   part ack'ed by Rob Herring)

 + fw loading re-work with helper to handle either /lib/firmware/qcom/$fw
   or /lib/firmware/$fw.. background, we've started landing fw for some of
   generations in linux-firmware, but there is a preference to put fw files
   under 'qcom' subdirectory, which is not what was done on android or for
   people who copied fw from android.  So now we first look in qcom subdir
   and then fallback to the original location.

 + bunch of GPU debugging enhancements, to dump full cmdline of processes
   that trigger faults, and to add a new debugfs to capture cmdstream of
   just submits that triggered faults.. both quite useful for piglit ;-)

* tag 'drm-msm-next-2017-11-01' of git://people.freedesktop.org/~robclark/linux: (38 commits)
  drm/msm: use %z format modifier for printing size_t
  drm/msm/mdp5: Don't use async plane update path if plane visibility changes
  drm/msm/mdp5: mdp5_crtc: Restore cursor state only if LM cursors are enabled
  drm/msm/mdp5: Update mdp5_pipe_assign to spit out both planes
  drm/msm/mdp5: Prepare mdp5_pipe_assign for some rework
  drm/msm: remove mdp5_cursor_plane_funcs
  drm/msm: update cursors asynchronously through atomic
  drm/msm/atomic: switch to drm_atomic_helper_check
  drm/msm/mdp5: restore cursor state when enabling crtc
  drm/msm/mdp5: don't use autosuspend
  drm/msm/mdp5: ignore planes that are not visible
  drm/msm: dump submits which triggered gpu hang
  drm/msm: preserve IOVAs in submit's bo table
  drm/msm/rd: allow adding addition msg to top of dump
  drm/msm: split rd debugfs file
  drm/msm: add special _get_vaddr_active() for cmdstream dumps
  drm/msm: show task cmdline in gpu recovery messages
  drm/msm: dump a rd GPUADDR header for all buffers in the command
  drm/msm: Removed unused struct_mutex_task
  drm/msm: Implement preemption for A5XX targets
  ...
2017-11-02 11:29:28 +10:00
Arnd Bergmann
39ae0d3e56 drm/msm: use %z format modifier for printing size_t
The return type of ARRAY_SIZE() is size_t, so we have to use
%zu instead of %lu to avoid this warning:

drivers/gpu/drm/msm/msm_gpu.c: In function 'msm_gpu_init':
drivers/gpu/drm/msm/msm_gpu.c:742:31: error: format '%lu' expects argument of type 'long unsigned int', but argument 7 has type 'unsigned int' [-Werror=format=]

The warning it otherwise harmless as size_t is always the
same size as unsigned long in all supported architectures,
but gcc doesn't know that.

Fixes: c2fceabca6d5 ("drm/msm: Support multiple ringbuffers")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rob Clark <robdclark@gmail.com>
2017-11-01 11:16:28 -04:00
Peter Griffin
a2f0424307 drm/hisilicon: Ensure LDI regs are properly configured.
This patch fixes the following soft lockup:
  BUG: soft lockup - CPU#0 stuck for 23s! [weston:307]

On weston idle-timeout the IP is powered down and reset
asserted. On weston resume we get a massive vblank
IRQ storm due to the LDI registers having lost some state.

This state loss is caused by ade_crtc_atomic_begin() not
calling ade_ldi_set_mode(). With this patch applied
resuming from Weston idle-timeout works well.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Cc: stable@vger.kernel.org
Reviewed-by: Xinliang Liu <xinliang.liu@linaro.org>
Signed-off-by: Xinliang Liu <xinliang.liu@linaro.org>
2017-11-01 10:36:50 +08:00
Linus Torvalds
0b07194bb5 Linux 4.14-rc7 2017-10-29 13:58:38 -07:00
Linus Torvalds
19e12196da Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Fix route leak in xfrm_bundle_create().

 2) In mac80211, validate user rate mask before configuring it. From
    Johannes Berg.

 3) Properly enforce memory limits in fair queueing code, from Toke
    Hoiland-Jorgensen.

 4) Fix lockdep splat in inet_csk_route_req(), from Eric Dumazet.

 5) Fix TSO header allocation and management in mvpp2 driver, from Yan
    Markman.

 6) Don't take socket lock in BH handler in strparser code, from Tom
    Herbert.

 7) Don't show sockets from other namespaces in AF_UNIX code, from
    Andrei Vagin.

 8) Fix double free in error path of tap_open(), from Girish Moodalbail.

 9) Fix TX map failure path in igb and ixgbe, from Jean-Philippe Brucker
    and Alexander Duyck.

10) Fix DCB mode programming in stmmac driver, from Jose Abreu.

11) Fix err_count handling in various tunnels (ipip, ip6_gre). From Xin
    Long.

12) Properly align SKB head before building SKB in tuntap, from Jason
    Wang.

13) Avoid matching qdiscs with a zero handle during lookups, from Cong
    Wang.

14) Fix various endianness bugs in sctp, from Xin Long.

15) Fix tc filter callback races and add selftests which trigger the
    problem, from Cong Wang.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (73 commits)
  selftests: Introduce a new test case to tc testsuite
  selftests: Introduce a new script to generate tc batch file
  net_sched: fix call_rcu() race on act_sample module removal
  net_sched: add rtnl assertion to tcf_exts_destroy()
  net_sched: use tcf_queue_work() in tcindex filter
  net_sched: use tcf_queue_work() in rsvp filter
  net_sched: use tcf_queue_work() in route filter
  net_sched: use tcf_queue_work() in u32 filter
  net_sched: use tcf_queue_work() in matchall filter
  net_sched: use tcf_queue_work() in fw filter
  net_sched: use tcf_queue_work() in flower filter
  net_sched: use tcf_queue_work() in flow filter
  net_sched: use tcf_queue_work() in cgroup filter
  net_sched: use tcf_queue_work() in bpf filter
  net_sched: use tcf_queue_work() in basic filter
  net_sched: introduce a workqueue for RCU callbacks of tc filter
  sctp: fix some type cast warnings introduced since very beginning
  sctp: fix a type cast warnings that causes a_rwnd gets the wrong value
  sctp: fix some type cast warnings introduced by transport rhashtable
  sctp: fix some type cast warnings introduced by stream reconf
  ...
2017-10-29 08:11:49 -07:00
David S. Miller
6c325f4eca Merge branch 'net_sched-fix-races-with-RCU-callbacks'
Cong Wang says:

====================
net_sched: fix races with RCU callbacks

Recently, the RCU callbacks used in TC filters and TC actions keep
drawing my attention, they introduce at least 4 race condition bugs:

1. A simple one fixed by Daniel:

commit c78e1746d3
Author: Daniel Borkmann <daniel@iogearbox.net>
Date:   Wed May 20 17:13:33 2015 +0200

    net: sched: fix call_rcu() race on classifier module unloads

2. A very nasty one fixed by me:

commit 1697c4bb52
Author: Cong Wang <xiyou.wangcong@gmail.com>
Date:   Mon Sep 11 16:33:32 2017 -0700

    net_sched: carefully handle tcf_block_put()

3. Two more bugs found by Chris:
https://patchwork.ozlabs.org/patch/826696/
https://patchwork.ozlabs.org/patch/826695/

Usually RCU callbacks are simple, however for TC filters and actions,
they are complex because at least TC actions could be destroyed
together with the TC filter in one callback. And RCU callbacks are
invoked in BH context, without locking they are parallel too. All of
these contribute to the cause of these nasty bugs.

Alternatively, we could also:

a) Introduce a spinlock to serialize these RCU callbacks. But as I
said in commit 1697c4bb52 ("net_sched: carefully handle
tcf_block_put()"), it is very hard to do because of tcf_chain_dump().
Potentially we need to do a lot of work to make it possible (if not
impossible).

b) Just get rid of these RCU callbacks, because they are not
necessary at all, callers of these call_rcu() are all on slow paths
and holding RTNL lock, so blocking is allowed in their contexts.
However, David and Eric dislike adding synchronize_rcu() here.

As suggested by Paul, we could defer the work to a workqueue and
gain the permission of holding RTNL again without any performance
impact, however, in tcf_block_put() we could have a deadlock when
flushing workqueue while hodling RTNL lock, the trick here is to
defer the work itself in workqueue and make it queued after all
other works so that we keep the same ordering to avoid any
use-after-free. Please see the first patch for details.

Patch 1 introduces the infrastructure, patch 2~12 move each
tc filter to the new tc filter workqueue, patch 13 adds
an assertion to catch potential bugs like this, patch 14
closes another rcu callback race, patch 15 and patch 16 add
new test cases.
====================

Reported-by: Chris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-29 22:49:32 +09:00