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120f28a6f3
Get rid of the crit lock.
That frees us from the error prone logic of try_locks.
Thanks to netdev_lock() by Jakub it is now easy, and in most cases we were
protected by it already - replace crit lock by netdev lock when it was not
the case.
Lockdep reports that we should cancel the work under crit_lock [splat1],
and that was the scheme we have mostly followed since [1] by Slawomir.
But when that is done we still got into deadlocks [splat2]. So instead
we should look at the bigger problem, namely "weird locking/scheduling"
of the iavf. The first step to fix that is to remove the crit lock.
I will followup with a -next series that simplifies scheduling/tasks.
Cancel the work without netdev lock (weird unlock+lock scheme),
to fix the [splat2] (which would be totally ugly if we would kept
the crit lock).
Extend protected part of iavf_watchdog_task() to include scheduling
more work.
Note that the removed comment in iavf_reset_task() was misplaced,
it belonged to inside of the removed if condition, so it's gone now.
[splat1] - w/o this patch - The deadlock during VF removal:
WARNING: possible circular locking dependency detected
sh/3825 is trying to acquire lock:
((work_completion)(&(&adapter->watchdog_task)->work)){+.+.}-{0:0}, at: start_flush_work+0x1a1/0x470
but task is already holding lock:
(&adapter->crit_lock){+.+.}-{4:4}, at: iavf_remove+0xd1/0x690 [iavf]
which lock already depends on the new lock.
[splat2] - when cancelling work under crit lock, w/o this series,
see [2] for the band aid attempt
WARNING: possible circular locking dependency detected
sh/3550 is trying to acquire lock:
((wq_completion)iavf){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x26/0x90
but task is already holding lock:
(&dev->lock){+.+.}-{4:4}, at: iavf_remove+0xa6/0x6e0 [iavf]
which lock already depends on the new lock.
[1]
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|---|---|---|
| .. | ||
| iavf_adminq_cmd.h | ||
| iavf_adminq.c | ||
| iavf_adminq.h | ||
| iavf_adv_rss.c | ||
| iavf_adv_rss.h | ||
| iavf_alloc.h | ||
| iavf_common.c | ||
| iavf_devids.h | ||
| iavf_ethtool.c | ||
| iavf_fdir.c | ||
| iavf_fdir.h | ||
| iavf_main.c | ||
| iavf_osdep.h | ||
| iavf_prototype.h | ||
| iavf_ptp.c | ||
| iavf_ptp.h | ||
| iavf_register.h | ||
| iavf_status.h | ||
| iavf_trace.h | ||
| iavf_txrx.c | ||
| iavf_txrx.h | ||
| iavf_type.h | ||
| iavf_types.h | ||
| iavf_virtchnl.c | ||
| iavf.h | ||
| Makefile | ||