Commit 02b9aa10 authored by Edwin Peer's avatar Edwin Peer Committed by David S. Miller
Browse files

bnxt_en: discard out of sequence HWRM responses 



During firmware crash recovery, it is possible for firmware to respond
to stale HWRM commands that have already timed out. Because response
buffers may be reused, any out of sequence responses need to be ignored
and only the matching seq_id should be accepted.

Also, READ_ONCE should be used for the reads from the DMA buffer to
ensure that the necessary loads are scheduled.

Reviewed-by: default avatarScott Branden <scott.branden@broadcom.com>
Signed-off-by: default avatarEdwin Peer <edwin.peer@broadcom.com>
Signed-off-by: default avatarMichael Chan <michael.chan@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f9ff5782

drivers/net/ethernet/broadcom/bnxt/bnxt_hwrm.c

+17 −4
Original line number Diff line number Diff line
@@ -399,9 +399,10 @@ static int __hwrm_send(struct bnxt *bp, struct bnxt_hwrm_ctx *ctx) 
					   le16_to_cpu(ctx->req->req_type));

			goto exit;

		}

		len = le16_to_cpu(ctx->resp->resp_len);

		len = le16_to_cpu(READ_ONCE(ctx->resp->resp_len));

		valid = ((u8 *)ctx->resp) + len - 1;

	} else {

		__le16 seen_out_of_seq = ctx->req->seq_id; /* will never see */

		int j;



		/* Check if response len is updated */
@@ -411,9 +412,21 @@ static int __hwrm_send(struct bnxt *bp, struct bnxt_hwrm_ctx *ctx) 
			 */

			if (test_bit(BNXT_STATE_FW_FATAL_COND, &bp->state))

				goto exit;

			len = le16_to_cpu(ctx->resp->resp_len);

			if (len)

			len = le16_to_cpu(READ_ONCE(ctx->resp->resp_len));

			if (len) {

				__le16 resp_seq = READ_ONCE(ctx->resp->seq_id);



				if (resp_seq == ctx->req->seq_id)

					break;

				if (resp_seq != seen_out_of_seq) {

					netdev_warn(bp->dev, "Discarding out of seq response: 0x%x for msg {0x%x 0x%x}\n",

						    le16_to_cpu(resp_seq),

						    le16_to_cpu(ctx->req->req_type),

						    le16_to_cpu(ctx->req->seq_id));

					seen_out_of_seq = resp_seq;

				}

			}



			/* on first few passes, just barely sleep */

			if (i < HWRM_SHORT_TIMEOUT_COUNTER) {

				usleep_range(HWRM_SHORT_MIN_TIMEOUT,