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Johannes Berg 9b9c910ccc mac80211: fix TXQ AC confusion 
commit 1153a74768 upstream.

Normally, TXQs have

  txq->tid = tid;
  txq->ac = ieee80211_ac_from_tid(tid);

However, the special management TXQ actually has

  txq->tid = IEEE80211_NUM_TIDS; // 16
  txq->ac = IEEE80211_AC_VO;

This makes sense, but ieee80211_ac_from_tid(16) is the same
as ieee80211_ac_from_tid(0) which is just IEEE80211_AC_BE.

Now, normally this is fine. However, if the netdev queues
were stopped, then the code in ieee80211_tx_dequeue() will
propagate the stop from the interface (vif->txqs_stopped[])
if the AC 2 (ieee80211_ac_from_tid(txq->tid)) is marked as
stopped. On wake, however, __ieee80211_wake_txqs() will wake
the TXQ if AC 0 (txq->ac) is woken up.

If a driver stops all queues with ieee80211_stop_tx_queues()
and then wakes them again with ieee80211_wake_tx_queues(),
the ieee80211_wake_txqs() tasklet will run to resync queue
and TXQ state. If all queues were woken, then what'll happen
is that _ieee80211_wake_txqs() will run in order of HW queues
0-3, typically (and certainly for iwlwifi) corresponding to
ACs 0-3, so it'll call __ieee80211_wake_txqs() for each AC in
order 0-3.

When __ieee80211_wake_txqs() is called for AC 0 (VO) that'll
wake up the management TXQ (remember its tid is 16), and the
driver's wake_tx_queue() will be called. That tries to get a
frame, which will immediately *stop* the TXQ again, because
now we check against AC 2, and AC 2 hasn't yet been marked as
woken up again in sdata->vif.txqs_stopped[] since we're only
in the __ieee80211_wake_txqs() call for AC 0.

Thus, the management TXQ will never be started again.

Fix this by checking txq->ac directly instead of calculating
the AC as ieee80211_ac_from_tid(txq->tid).

Fixes: adf8ed01e4 ("mac80211: add an optional TXQ for other PS-buffered frames")
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20210323210500.bf4d50afea4a.I136ffde910486301f8818f5442e3c9bf8670a9c4@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-14 08:42:02 +02:00
arch ARM: dts: turris-omnia: configure LED[2]/INTn pin as interrupt pin 2021-04-14 08:41:59 +02:00
block block: recalculate segment count for multi-segment discards correctly 2021-03-30 14:32:06 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 11:37:59 +01:00
crypto crypto: mips/poly1305 - enable for all MIPS processors 2021-03-17 17:06:10 +01:00
Documentation KVM: x86: Protect userspace MSR filter with SRCU, and set atomically-ish 2021-03-30 14:31:53 +02:00
drivers vdpa/mlx5: Fix suspend/resume index restoration 2021-04-14 08:42:01 +02:00
fs fs: direct-io: fix missing sdio->boundary 2021-04-14 08:41:58 +02:00
include net: sched: fix action overwrite reference counting 2021-04-14 08:42:02 +02:00
init init/Kconfig: make COMPILE_TEST depend on HAS_IOMEM 2021-04-10 13:36:11 +02:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel bpf: Refcount task stack in bpf_get_task_stack 2021-04-14 08:42:01 +02:00
lib math: Export mul_u64_u64_div_u64 2021-04-10 13:36:10 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm: fix race by making init_zero_pfn() early_initcall 2021-04-07 15:00:10 +02:00
net mac80211: fix TXQ AC confusion 2021-04-14 08:42:02 +02:00
samples samples, bpf: Add missing munmap in xdpsock 2021-03-17 17:06:12 +01:00
scripts kbuild: dummy-tools: fix inverted tests for gcc 2021-03-30 14:31:50 +02:00
security selinux: fix race between old and new sidtab 2021-04-14 08:41:57 +02:00
sound ASoC: intel: atom: Stop advertising non working S24LE support 2021-04-14 08:41:56 +02:00
tools libbpf: Only create rx and tx XDP rings when necessary 2021-04-14 08:42:01 +02:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: Use kvm_pfn_t for local PFN variable in hva_to_pfn_remapped() 2021-02-26 10:13:01 +01:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: move the staging subsystem to lists.linux.dev 2021-03-25 09:04:18 +01:00
Makefile Linux 5.10.29 2021-04-10 13:36:11 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.