sfc: suppress duplicate nvmem partition types in efx_ef10_mtd_probe

Use a bitmap to keep track of which partition types we've already seen;
 for duplicates, return -EEXIST from efx_ef10_mtd_probe_partition() and
 thus skip adding that partition.
Duplicate partitions occur because of the A/B backup scheme used by newer
 sfc NICs.  Prior to this patch they cause sysfs_warn_dup errors because
 they have the same name, causing us not to expose any MTDs at all.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index b6a5005..2f2bda6 100644 (file)
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -6046,22 +6046,25 @@ static const struct efx_ef10_nvram_type_info efx_ef10_nvram_types[] = {
        { NVRAM_PARTITION_TYPE_EXPANSION_UEFI,     0,    0, "sfc_uefi" },
        { NVRAM_PARTITION_TYPE_STATUS,             0,    0, "sfc_status" }
 };
+#define EF10_NVRAM_PARTITION_COUNT     ARRAY_SIZE(efx_ef10_nvram_types)
 
 static int efx_ef10_mtd_probe_partition(struct efx_nic *efx,
                                        struct efx_mcdi_mtd_partition *part,
-                                       unsigned int type)
+                                       unsigned int type,
+                                       unsigned long *found)
 {
        MCDI_DECLARE_BUF(inbuf, MC_CMD_NVRAM_METADATA_IN_LEN);
        MCDI_DECLARE_BUF(outbuf, MC_CMD_NVRAM_METADATA_OUT_LENMAX);
        const struct efx_ef10_nvram_type_info *info;
        size_t size, erase_size, outlen;
+       int type_idx = 0;
        bool protected;
        int rc;
 
-       for (info = efx_ef10_nvram_types; ; info++) {
-               if (info ==
-                   efx_ef10_nvram_types + ARRAY_SIZE(efx_ef10_nvram_types))
+       for (type_idx = 0; ; type_idx++) {
+               if (type_idx == EF10_NVRAM_PARTITION_COUNT)
                        return -ENODEV;
+               info = efx_ef10_nvram_types + type_idx;
                if ((type & ~info->type_mask) == info->type)
                        break;
        }
@@ -6074,6 +6077,13 @@ static int efx_ef10_mtd_probe_partition(struct efx_nic *efx,
        if (protected)
                return -ENODEV; /* hide it */
 
+       /* If we've already exposed a partition of this type, hide this
+        * duplicate.  All operations on MTDs are keyed by the type anyway,
+        * so we can't act on the duplicate.
+        */
+       if (__test_and_set_bit(type_idx, found))
+               return -EEXIST;
+
        part->nvram_type = type;
 
        MCDI_SET_DWORD(inbuf, NVRAM_METADATA_IN_TYPE, type);
@@ -6105,6 +6115,7 @@ static int efx_ef10_mtd_probe_partition(struct efx_nic *efx,
 static int efx_ef10_mtd_probe(struct efx_nic *efx)
 {
        MCDI_DECLARE_BUF(outbuf, MC_CMD_NVRAM_PARTITIONS_OUT_LENMAX);
+       DECLARE_BITMAP(found, EF10_NVRAM_PARTITION_COUNT);
        struct efx_mcdi_mtd_partition *parts;
        size_t outlen, n_parts_total, i, n_parts;
        unsigned int type;
@@ -6133,11 +6144,13 @@ static int efx_ef10_mtd_probe(struct efx_nic *efx)
        for (i = 0; i < n_parts_total; i++) {
                type = MCDI_ARRAY_DWORD(outbuf, NVRAM_PARTITIONS_OUT_TYPE_ID,
                                        i);
-               rc = efx_ef10_mtd_probe_partition(efx, &parts[n_parts], type);
-               if (rc == 0)
-                       n_parts++;
-               else if (rc != -ENODEV)
+               rc = efx_ef10_mtd_probe_partition(efx, &parts[n_parts], type,
+                                                 found);
+               if (rc == -EEXIST || rc == -ENODEV)
+                       continue;
+               if (rc)
                        goto fail;
+               n_parts++;
        }
 
        rc = efx_mtd_add(efx, &parts[0].common, n_parts, sizeof(*parts));