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author | Paolo Abeni <pabeni@redhat.com> | 2021-04-09 18:24:17 +0300 |
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committer | Jakub Kicinski <kuba@kernel.org> | 2021-04-09 22:50:31 +0300 |
commit | 27f0ad71699de41bae013c367b95a6b319cc46a9 (patch) | |
tree | f74e446319f81d7d42410f8b06b5a56235903c53 /drivers/mtd/mtdpart.c | |
parent | cd7e963d2f0875789ddb5c3746b628716bd0a8c9 (diff) | |
download | linux-27f0ad71699de41bae013c367b95a6b319cc46a9.tar.xz |
net: fix hangup on napi_disable for threaded napi
napi_disable() is subject to an hangup, when the threaded
mode is enabled and the napi is under heavy traffic.
If the relevant napi has been scheduled and the napi_disable()
kicks in before the next napi_threaded_wait() completes - so
that the latter quits due to the napi_disable_pending() condition,
the existing code leaves the NAPI_STATE_SCHED bit set and the
napi_disable() loop waiting for such bit will hang.
This patch addresses the issue by dropping the NAPI_STATE_DISABLE
bit test in napi_thread_wait(). The later napi_threaded_poll()
iteration will take care of clearing the NAPI_STATE_SCHED.
This also addresses a related problem reported by Jakub:
before this patch a napi_disable()/napi_enable() pair killed
the napi thread, effectively disabling the threaded mode.
On the patched kernel napi_disable() simply stops scheduling
the relevant thread.
v1 -> v2:
- let the main napi_thread_poll() loop clear the SCHED bit
Reported-by: Jakub Kicinski <kuba@kernel.org>
Fixes: 29863d41bb6e ("net: implement threaded-able napi poll loop support")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/883923fa22745a9589e8610962b7dc59df09fb1f.1617981844.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/mtd/mtdpart.c')
0 files changed, 0 insertions, 0 deletions