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linux/drivers/infiniband/hw/qib/qib_verbs.c
Mike Marciniszyn 4894710951 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>
2012-01-03 20:53:31 -08:00

60 KiB