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Commit 107c3f4d authored by Michael Chan's avatar Michael Chan Committed by David S. Miller
Browse files

cnic: Prevent status block race conditions with hardware 



The status block index is used to acknowledge interrupt events and must
be read before checking for the interrupt events, so we need to add rmb()
to guarantee that.

Signed-off-by: default avatarMichael Chan <mchan@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1707be1b

drivers/net/cnic.c

+8 −0
Original line number Diff line number Diff line
@@ -2760,6 +2760,8 @@ static u32 cnic_service_bnx2_queues(struct cnic_dev *dev) 
	u32 status_idx = (u16) *cp->kcq1.status_idx_ptr;

	int kcqe_cnt;



	/* status block index must be read before reading other fields */

	rmb();

	cp->kwq_con_idx = *cp->kwq_con_idx_ptr;



	while ((kcqe_cnt = cnic_get_kcqes(dev, &cp->kcq1))) {
@@ -2770,6 +2772,8 @@ static u32 cnic_service_bnx2_queues(struct cnic_dev *dev) 
		barrier();

		if (status_idx != *cp->kcq1.status_idx_ptr) {

			status_idx = (u16) *cp->kcq1.status_idx_ptr;

			/* status block index must be read first */

			rmb();

			cp->kwq_con_idx = *cp->kwq_con_idx_ptr;

		} else

			break;
@@ -2888,6 +2892,8 @@ static u32 cnic_service_bnx2x_kcq(struct cnic_dev *dev, struct kcq_info *info) 
	u32 last_status = *info->status_idx_ptr;

	int kcqe_cnt;



	/* status block index must be read before reading the KCQ */

	rmb();

	while ((kcqe_cnt = cnic_get_kcqes(dev, info))) {



		service_kcqes(dev, kcqe_cnt);
@@ -2898,6 +2904,8 @@ static u32 cnic_service_bnx2x_kcq(struct cnic_dev *dev, struct kcq_info *info) 
			break;



		last_status = *info->status_idx_ptr;

		/* status block index must be read before reading the KCQ */

		rmb();

	}

	return last_status;

}