From: Edward Cree <ecree@solarflare.com>
Date: Tue, 27 Mar 2018 17:44:21 +0100
Subject: sfc: return a better error if filter insertion collides with MC
 reboot
Patch-mainline: v4.17-rc1
Git-commit: 31b842955211f427a099f78a6a63d18a6bbc8d55
References: bsc#1105555 FATE#326117

If some other operation gets the MCDI lock ahead of us and performs an MC
 reboot, then our attempt to insert the filter will fail with EINVAL,
 because the destination VI (spec->dmaq_id, MC_CMD_FILTER_OP_IN_RX_QUEUE) does
 not exist.  But the caller's request (which might e.g. be an ethtool ntuple
 request from userland) isn't invalid, it just got unlucky; so return EAGAIN.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/sfc/ef10.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -4301,6 +4301,7 @@ static s32 efx_ef10_filter_insert(struct
 				  bool replace_equal)
 {
 	DECLARE_BITMAP(mc_rem_map, EFX_EF10_FILTER_SEARCH_LIMIT);
+	struct efx_ef10_nic_data *nic_data = efx->nic_data;
 	struct efx_ef10_filter_table *table;
 	struct efx_filter_spec *saved_spec;
 	struct efx_rss_context *ctx = NULL;
@@ -4427,6 +4428,12 @@ static s32 efx_ef10_filter_insert(struct
 	rc = efx_ef10_filter_push(efx, spec, &table->entry[ins_index].handle,
 				  ctx, replacing);
 
+	if (rc == -EINVAL && nic_data->must_realloc_vis)
+		/* The MC rebooted under us, causing it to reject our filter
+		 * insertion as pointing to an invalid VI (spec->dmaq_id).
+		 */
+		rc = -EAGAIN;
+
 	/* Finalise the software table entry */
 	if (rc == 0) {
 		if (replacing) {