[PATCH for-next 02/17] RDMA/bnxt_re: Avoid calling wake_up threads from spin_lock context

[Selvin Xavier <selvin.xavier@broadcom.com>]

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From: Kashyap Desai <kashyap.desai@broadcom.com>

bnxt_qplib_service_creq can be called from interrupt or tasklet or
process context. So the function take irq variant  of spin_lock.
But when wake_up is invoked with the lock held, it is putting the
calling context to sleep.

[exception RIP: __wake_up_common+190]
RIP: ffffffffb7539d7e  RSP: ffffa73300207ad8  RFLAGS: 00000083
RAX: 0000000000000001  RBX: ffff91fa295f69b8  RCX: dead000000000200
RDX: ffffa733344af940  RSI: ffffa73336527940  RDI: ffffa73336527940
RBP: 000000000000001c   R8: 0000000000000002   R9: 00000000000299c0
R10: 0000017230de82c5  R11: 0000000000000002  R12: ffffa73300207b28
R13: 0000000000000000  R14: ffffa733341bf928  R15: 0000000000000000
ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018

Call the wakeup after releasing the lock.

Fixes: 1ac5a4047975 ("RDMA/bnxt_re: Add bnxt_re RoCE driver")
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
---
 drivers/infiniband/hw/bnxt_re/qplib_rcfw.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
index d4ce82b..c11b8e7 100644
--- a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
+++ b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
@@ -295,7 +295,8 @@ static int bnxt_qplib_process_func_event(struct bnxt_qplib_rcfw *rcfw,
 }
 
 static int bnxt_qplib_process_qp_event(struct bnxt_qplib_rcfw *rcfw,
-				       struct creq_qp_event *qp_event)
+				       struct creq_qp_event *qp_event,
+				       u32 *num_wait)
 {
 	struct creq_qp_error_notification *err_event;
 	struct bnxt_qplib_hwq *hwq = &rcfw->cmdq.hwq;
@@ -304,6 +305,7 @@ static int bnxt_qplib_process_qp_event(struct bnxt_qplib_rcfw *rcfw,
 	u16 cbit, blocked = 0;
 	struct pci_dev *pdev;
 	unsigned long flags;
+	u32 wait_cmds = 0;
 	__le16  mcookie;
 	u16 cookie;
 	int rc = 0;
@@ -363,9 +365,10 @@ static int bnxt_qplib_process_qp_event(struct bnxt_qplib_rcfw *rcfw,
 		crsqe->req_size = 0;
 
 		if (!blocked)
-			wake_up(&rcfw->cmdq.waitq);
+			wait_cmds++;
 		spin_unlock_irqrestore(&hwq->lock, flags);
 	}
+	*num_wait += wait_cmds;
 	return rc;
 }
 
@@ -379,6 +382,7 @@ static void bnxt_qplib_service_creq(struct tasklet_struct *t)
 	struct creq_base *creqe;
 	u32 sw_cons, raw_cons;
 	unsigned long flags;
+	u32 num_wakeup = 0;
 
 	/* Service the CREQ until budget is over */
 	spin_lock_irqsave(&hwq->lock, flags);
@@ -397,7 +401,8 @@ static void bnxt_qplib_service_creq(struct tasklet_struct *t)
 		switch (type) {
 		case CREQ_BASE_TYPE_QP_EVENT:
 			bnxt_qplib_process_qp_event
-				(rcfw, (struct creq_qp_event *)creqe);
+				(rcfw, (struct creq_qp_event *)creqe,
+				 &num_wakeup);
 			creq->stats.creq_qp_event_processed++;
 			break;
 		case CREQ_BASE_TYPE_FUNC_EVENT:
@@ -425,6 +430,8 @@ static void bnxt_qplib_service_creq(struct tasklet_struct *t)
 				      rcfw->res->cctx, true);
 	}
 	spin_unlock_irqrestore(&hwq->lock, flags);
+	if (num_wakeup)
+		wake_up_nr(&rcfw->cmdq.waitq, num_wakeup);
 }
 
 static irqreturn_t bnxt_qplib_creq_irq(int irq, void *dev_instance)
-- 
2.5.5


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