IB/hf1: User context locking is inconsistent

There is a mixture of mutex and spinlocks to protect receive context
(rcd/uctxt) information.  This is not used consistently.

Use the mutex to protect device receive context information only.
Use the spinlock to protect sub context information only.

Protect access to items in the rcd array with a spinlock and
reference count.

Remove spinlock around dd->rcd array cleanup.  Since interrupts are
disabled and cleaned up before this point, this lock is not useful.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 47 insertions, 24 deletions

diff --git a/drivers/infiniband/hw/hfi1/driver.c b/drivers/infiniband/hw/hfi1/driver.c
index 0b7ca0e05320..14f2a00c13c2 100644
--- a/drivers/infiniband/hw/hfi1/driver.c
+++ b/drivers/infiniband/hw/hfi1/driver.c
@@ -839,6 +839,7 @@ bail:
 
 static inline void set_nodma_rtail(struct hfi1_devdata *dd, u16 ctxt)
 {
+	struct hfi1_ctxtdata *rcd;
 	u16 i;
 
 	/*
@@ -847,18 +848,27 @@ static inline void set_nodma_rtail(struct hfi1_devdata *dd, u16 ctxt)
 	 * interrupt handler for all statically allocated kernel contexts.
 	 */
 	if (ctxt >= dd->first_dyn_alloc_ctxt) {
-		dd->rcd[ctxt]->do_interrupt =
-			&handle_receive_interrupt_nodma_rtail;
+		rcd = hfi1_rcd_get_by_index(dd, ctxt);
+		if (rcd) {
+			rcd->do_interrupt =
+				&handle_receive_interrupt_nodma_rtail;
+			hfi1_rcd_put(rcd);
+		}
 		return;
 	}
 
-	for (i = HFI1_CTRL_CTXT + 1; i < dd->first_dyn_alloc_ctxt; i++)
-		dd->rcd[i]->do_interrupt =
-			&handle_receive_interrupt_nodma_rtail;
+	for (i = HFI1_CTRL_CTXT + 1; i < dd->first_dyn_alloc_ctxt; i++) {
+		rcd = hfi1_rcd_get_by_index(dd, i);
+		if (rcd)
+			rcd->do_interrupt =
+				&handle_receive_interrupt_nodma_rtail;
+		hfi1_rcd_put(rcd);
+	}
 }
 
 static inline void set_dma_rtail(struct hfi1_devdata *dd, u16 ctxt)
 {
+	struct hfi1_ctxtdata *rcd;
 	u16 i;
 
 	/*
@@ -867,27 +877,39 @@ static inline void set_dma_rtail(struct hfi1_devdata *dd, u16 ctxt)
 	 * interrupt handler for all statically allocated kernel contexts.
 	 */
 	if (ctxt >= dd->first_dyn_alloc_ctxt) {
-		dd->rcd[ctxt]->do_interrupt =
-			&handle_receive_interrupt_dma_rtail;
+		rcd = hfi1_rcd_get_by_index(dd, ctxt);
+		if (rcd) {
+			rcd->do_interrupt =
+				&handle_receive_interrupt_dma_rtail;
+			hfi1_rcd_put(rcd);
+		}
 		return;
 	}
 
-	for (i = HFI1_CTRL_CTXT + 1; i < dd->first_dyn_alloc_ctxt; i++)
-		dd->rcd[i]->do_interrupt =
-			&handle_receive_interrupt_dma_rtail;
+	for (i = HFI1_CTRL_CTXT + 1; i < dd->first_dyn_alloc_ctxt; i++) {
+		rcd = hfi1_rcd_get_by_index(dd, i);
+		if (rcd)
+			rcd->do_interrupt =
+				&handle_receive_interrupt_dma_rtail;
+		hfi1_rcd_put(rcd);
+	}
 }
 
 void set_all_slowpath(struct hfi1_devdata *dd)
 {
+	struct hfi1_ctxtdata *rcd;
 	u16 i;
 
 	/* HFI1_CTRL_CTXT must always use the slow path interrupt handler */
 	for (i = HFI1_CTRL_CTXT + 1; i < dd->num_rcv_contexts; i++) {
-		struct hfi1_ctxtdata *rcd = dd->rcd[i];
-
+		rcd = hfi1_rcd_get_by_index(dd, i);
+		if (!rcd)
+			continue;
 		if ((i < dd->first_dyn_alloc_ctxt) ||
-		    (rcd && rcd->sc && (rcd->sc->type == SC_KERNEL)))
+		    (rcd->sc && (rcd->sc->type == SC_KERNEL))) {
 			rcd->do_interrupt = &handle_receive_interrupt;
+		}
+		hfi1_rcd_put(rcd);
 	}
 }
 
@@ -1068,6 +1090,7 @@ void receive_interrupt_work(struct work_struct *work)
 	struct hfi1_pportdata *ppd = container_of(work, struct hfi1_pportdata,
 						  linkstate_active_work);
 	struct hfi1_devdata *dd = ppd->dd;
+	struct hfi1_ctxtdata *rcd;
 	u16 i;
 
 	/* Received non-SC15 packet implies neighbor_normal */
@@ -1078,8 +1101,12 @@ void receive_interrupt_work(struct work_struct *work)
 	 * Interrupt all statically allocated kernel contexts that could
 	 * have had an interrupt during auto activation.
 	 */
-	for (i = HFI1_CTRL_CTXT; i < dd->first_dyn_alloc_ctxt; i++)
-		force_recv_intr(dd->rcd[i]);
+	for (i = HFI1_CTRL_CTXT; i < dd->first_dyn_alloc_ctxt; i++) {
+		rcd = hfi1_rcd_get_by_index(dd, i);
+		if (rcd)
+			force_recv_intr(rcd);
+		hfi1_rcd_put(rcd);
+	}
 }
 
 /*
@@ -1270,10 +1297,8 @@ void hfi1_start_led_override(struct hfi1_pportdata *ppd, unsigned int timeon,
 int hfi1_reset_device(int unit)
 {
 	int ret;
-	u16 i;
 	struct hfi1_devdata *dd = hfi1_lookup(unit);
 	struct hfi1_pportdata *ppd;
-	unsigned long flags;
 	int pidx;
 
 	if (!dd) {
@@ -1291,17 +1316,15 @@ int hfi1_reset_device(int unit)
 		goto bail;
 	}
 
-	spin_lock_irqsave(&dd->uctxt_lock, flags);
+	/* If there are any user/vnic contexts, we cannot reset */
+	mutex_lock(&hfi1_mutex);
 	if (dd->rcd)
-		for (i = dd->first_dyn_alloc_ctxt;
-		     i < dd->num_rcv_contexts; i++) {
-			if (!dd->rcd[i])
-				continue;
-			spin_unlock_irqrestore(&dd->uctxt_lock, flags);
+		if (hfi1_stats.sps_ctxts) {
+			mutex_unlock(&hfi1_mutex);
 			ret = -EBUSY;
 			goto bail;
 		}
-	spin_unlock_irqrestore(&dd->uctxt_lock, flags);
+	mutex_unlock(&hfi1_mutex);
 
 	for (pidx = 0; pidx < dd->num_pports; ++pidx) {
 		ppd = dd->pport + pidx;