diff mbox series

[net-next,05/11] bnxt_en: discard out of sequence HWRM responses

Message ID 1630187910-22252-6-git-send-email-michael.chan@broadcom.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series bnxt_en: Implement new driver APIs to send FW messages | expand

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netdev/source_inline success Was 0 now: 0
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netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 2 this patch: 2
netdev/kdoc success Errors and warnings before: 0 this patch: 0
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netdev/checkpatch warning WARNING: line length of 83 exceeds 80 columns WARNING: line length of 84 exceeds 80 columns
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
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Commit Message

Michael Chan Aug. 28, 2021, 9:58 p.m. UTC 
From: Edwin Peer <edwin.peer@broadcom.com>

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: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
 .../net/ethernet/broadcom/bnxt/bnxt_hwrm.c    | 21 +++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_hwrm.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_hwrm.c
index 91c4d3aac0b6..917d617afa87 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_hwrm.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_hwrm.c
@@ -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)
-				break;
+			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,