IB/hfi1: Reduce lock contention on iowait_lock for sdma and pio

Commit 4e045572e2 ("IB/hfi1: Add unique txwait_lock for txreq events")
laid the ground work to support per resource waiting locking.

This patch adds that with a lock unique to each sdma engine and pio
sendcontext and makes necessary changes for verbs, PSM, and vnic to use
the new locks.

This is particularly beneficial for smaller messages that will exhaust
resources at a faster rate.

Fixes: 7724105686 ("IB/hfi1: add driver files")
Reviewed-by: Gary Leshner <Gary.S.Leshner@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/hfi1/sdma.c

@@ -1424,6 +1424,7 @@ int sdma_init(struct hfi1_devdata *dd, u8 port)
 		seqlock_init(&sde->head_lock);
 		spin_lock_init(&sde->senddmactrl_lock);
 		spin_lock_init(&sde->flushlist_lock);
+		seqlock_init(&sde->waitlock);
 		/* insure there is always a zero bit */
 		sde->ahg_bits = 0xfffffffe00000000ULL;
 
@@ -1758,7 +1759,6 @@ static void sdma_desc_avail(struct sdma_engine *sde, uint avail)
 	struct iowait *wait, *nw;
 	struct iowait *waits[SDMA_WAIT_BATCH_SIZE];
 	uint i, n = 0, seq, max_idx = 0;
-	struct hfi1_ibdev *dev = &sde->dd->verbs_dev;
 	u8 max_starved_cnt = 0;
 
 #ifdef CONFIG_SDMA_VERBOSITY
@@ -1768,10 +1768,10 @@ static void sdma_desc_avail(struct sdma_engine *sde, uint avail)
 #endif
 
 	do {
-		seq = read_seqbegin(&dev->iowait_lock);
+		seq = read_seqbegin(&sde->waitlock);
 		if (!list_empty(&sde->dmawait)) {
 			/* at least one item */
-			write_seqlock(&dev->iowait_lock);
+			write_seqlock(&sde->waitlock);
 			/* Harvest waiters wanting DMA descriptors */
 			list_for_each_entry_safe(
 					wait,
@@ -1794,10 +1794,10 @@ static void sdma_desc_avail(struct sdma_engine *sde, uint avail)
 				list_del_init(&wait->list);
 				waits[n++] = wait;
 			}
-			write_sequnlock(&dev->iowait_lock);
+			write_sequnlock(&sde->waitlock);
 			break;
 		}
-	} while (read_seqretry(&dev->iowait_lock, seq));
+	} while (read_seqretry(&sde->waitlock, seq));
 
 	/* Schedule the most starved one first */
 	if (n)