[dpdk-dev] [PATCH 38/80] net/sfc/base: improve robustness of MAC stats get via MCDI

[Andrew Rybchenko]

From: Andy Moreton <amoreton at solarflare.com>

Previously the code relied on the callers of efx_mcdi_mac_stats
to provide a DMA buffer or NULL depnding on the action. Fix
this so that the DMA buffer is only passed in the request when
needed, and that an error is reported for a missing DMA buffer.

Signed-off-by: Andy Moreton <amoreton at solarflare.com>
Signed-off-by: Andrew Rybchenko <arybchenko at solarflare.com>
---
 drivers/net/sfc/base/efx_mcdi.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/net/sfc/base/efx_mcdi.c b/drivers/net/sfc/base/efx_mcdi.c
index 3352b08..a593b3f 100644
--- a/drivers/net/sfc/base/efx_mcdi.c
+++ b/drivers/net/sfc/base/efx_mcdi.c
@@ -1814,9 +1814,15 @@ efx_mcdi_mac_stats(
 	    MAC_STATS_IN_PERIODIC_NOEVENT, !events,
 	    MAC_STATS_IN_PERIOD_MS, (enable | events) ? period_ms : 0);
 
-	if (esmp != NULL) {
+	if (enable || events || upload) {
 		uint32_t bytes = MC_CMD_MAC_NSTATS * sizeof (uint64_t);
 
+		/* Periodic stats or stats upload require a DMA buffer */
+		if (esmp == NULL) {
+			rc = EINVAL;
+			goto fail1;
+		}
+
 		EFX_STATIC_ASSERT(MC_CMD_MAC_NSTATS * sizeof (uint64_t) <=
 		    EFX_MAC_STATS_SIZE);
 
@@ -1827,8 +1833,6 @@ efx_mcdi_mac_stats(
 		MCDI_IN_SET_DWORD(req, MAC_STATS_IN_DMA_ADDR_HI,
 			    EFSYS_MEM_ADDR(esmp) >> 32);
 		MCDI_IN_SET_DWORD(req, MAC_STATS_IN_DMA_LEN, bytes);
-	} else {
-		EFSYS_ASSERT(!upload && !enable && !events);
 	}
 
 	/*
@@ -1846,12 +1850,14 @@ efx_mcdi_mac_stats(
 		if ((req.emr_rc != ENOENT) ||
 		    (enp->en_rx_qcount + enp->en_tx_qcount != 0)) {
 			rc = req.emr_rc;
-			goto fail1;
+			goto fail2;
 		}
 	}
 
 	return (0);
 
+fail2:
+	EFSYS_PROBE(fail2);
 fail1:
 	EFSYS_PROBE1(fail1, efx_rc_t, rc);
 
-- 
2.7.4