Ppdu_stats are received from firmware in softirq context.
While inserting the ppdu_stats into a qdf list, a spinlock
is held for its access, same qdf list is accessed by mon
thread using spinlock. There can be a scenario in which
mon_thread held spinlock for accessing qdf_list and is
interrupted by softirq in which ppdu_stats are received.
This leads to softirq spinning for lock forever leading
to deadlock.
To address this issue, use spin_lock_bh instead of spin_lock.
Also reduce the time for which lock is taken to access the list
for insertion and removal of ppdu_stats.
Change-Id: I52171fe3c1d22a1e9d1ab36daac54d8fa2b96020
CRs-Fixed: 3136901
ef1f94f9d5