IB/qib: Optimize locking for get_txreq()
The current code locks the QP s_lock, followed by the pending_lock, I
guess to to protect against the allocate failing.
This patch only locks the pending_lock, assuming that the empty case
is an exeception, in which case the pending_lock is dropped, and the
original code is executed. This will save a lock of s_lock in the
normal case.
The observation is that the sdma descriptors will deplete at twice the
rate of txreq's, so this should be rare.
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
1 file changed