Thread (31 messages) 31 messages, 3 authors, 2026-01-23

Re: [net-next,v4,01/13] octeontx2-af: npc: cn20k: Index management

From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-01-18 00:40:20
Also in: lkml

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---
octeontx2-af: npc: cn20k: Index management

This patch adds MCAM index management for CN20K silicon, implementing
contiguous and non-contiguous allocation schemes with reference, limit,
and priority parameters across the new subbank architecture.
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c b/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c
new file mode 100644
index 000000000000..ebccc780ab8e
--- /dev/null
+++ b/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c
[ ... ]
+static int npc_idx_free(struct rvu *rvu, u16 *mcam_idx, int count,
+			bool maps_del)
+{
+	struct npc_subbank *sb;
+	int idx, i;
+	bool ret;
+	int rc;
+
+	for (i = 0; i < count; i++) {
+		rc =  npc_mcam_idx_2_subbank_idx(rvu, mcam_idx[i],
+						 &sb, &idx);
+		if (rc)
+			return rc;
+
+		ret = npc_subbank_free(rvu, sb, idx);
+		if (ret)
+			return -EINVAL;
If an error occurs partway through this loop, for example when freeing
entry i out of count entries, entries from i+1 to count-1 remain allocated
but are never freed. Could this leak MCAM slots when npc_idx_free() is
called from error paths in npc_multi_subbank_ref_alloc() or
npc_subbank_noref_alloc()?
+
+		if (!maps_del)
+			continue;
+
+		rc = npc_del_from_pf_maps(rvu, mcam_idx[i]);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
[ ... ]
+static int npc_priv_init(struct rvu *rvu)
+{
[ ... ]
+	npc_priv.sb = kcalloc(num_subbanks, sizeof(struct npc_subbank),
+			      GFP_KERNEL);
+	if (!npc_priv.sb)
+		return -ENOMEM;
+
+	xa_init_flags(&npc_priv.xa_sb_used, XA_FLAGS_ALLOC);
+	xa_init_flags(&npc_priv.xa_sb_free, XA_FLAGS_ALLOC);
+	xa_init_flags(&npc_priv.xa_idx2pf_map, XA_FLAGS_ALLOC);
+	xa_init_flags(&npc_priv.xa_pf_map, XA_FLAGS_ALLOC);
+
+	if (npc_create_srch_order(num_subbanks)) {
+		kfree(npc_priv.sb);
+		return -ENOMEM;
+	}
The four xarrays initialized above are not destroyed before returning
here. Should xa_destroy() be called for xa_sb_used, xa_sb_free,
xa_idx2pf_map, and xa_pf_map on this error path?

[ ... ]
+	npc_priv.xa_pf2idx_map = kcalloc(npc_priv.pf_cnt,
+					 sizeof(struct xarray),
+					 GFP_KERNEL);
+	if (!npc_priv.xa_pf2idx_map) {
+		kfree(subbank_srch_order);
+		kfree(npc_priv.sb);
+		return -ENOMEM;
+	}
Same question here - the four xarrays are still not destroyed on this
error path.
+
+	for (i = 0; i < npc_priv.pf_cnt; i++)
+		xa_init_flags(&npc_priv.xa_pf2idx_map[i], XA_FLAGS_ALLOC);
+
+	return 0;
+}
-- 
pw-bot: cr
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