[PATCH net-next v2 05/11] bnxt_en: discard out of sequence HWRM responses
From: Michael Chan <michael.chan@broadcom.com>
Date: 2021-08-29 07:35:35
Subsystem:
broadcom bnxt_en 50 gigabit ethernet driver, networking drivers, the rest · Maintainers:
Michael Chan, Pavan Chebbi, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Edwin Peer <redacted> 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 <redacted> 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 --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_hwrm.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_hwrm.c
index a45f2a619086..621daf687a00 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,
--
2.18.1
Attachments
- smime.p7s [application/pkcs7-signature] 4209 bytes