qed: Fix potential memory corruption

A stuck ramrod should be deleted from the completion_pending list,
otherwise it will be added again in the future and corrupt the list.

Return error value to inform that ramrod is stuck and should be deleted.
Signed-off-by: Sagiv Ozeri <sagiv.ozeri@cavium.com>
Signed-off-by: Denis Bolotin <denis.bolotin@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qed/qed_spq.c

@@ -142,6 +142,7 @@ static int qed_spq_block(struct qed_hwfn *p_hwfn,
 
 	DP_INFO(p_hwfn, "Ramrod is stuck, requesting MCP drain\n");
 	rc = qed_mcp_drain(p_hwfn, p_ptt);
+	qed_ptt_release(p_hwfn, p_ptt);
 	if (rc) {
 		DP_NOTICE(p_hwfn, "MCP drain failed\n");
 		goto err;
@@ -150,18 +151,15 @@ static int qed_spq_block(struct qed_hwfn *p_hwfn,
 	/* Retry after drain */
 	rc = __qed_spq_block(p_hwfn, p_ent, p_fw_ret, true);
 	if (!rc)
-		goto out;
+		return 0;
 
 	comp_done = (struct qed_spq_comp_done *)p_ent->comp_cb.cookie;
-	if (comp_done->done == 1)
+	if (comp_done->done == 1) {
 		if (p_fw_ret)
 			*p_fw_ret = comp_done->fw_return_code;
-out:
-	qed_ptt_release(p_hwfn, p_ptt);
-	return 0;
-
+		return 0;
+	}
 err:
-	qed_ptt_release(p_hwfn, p_ptt);
 	DP_NOTICE(p_hwfn,
 		  "Ramrod is stuck [CID %08x cmd %02x protocol %02x echo %04x]\n",
 		  le32_to_cpu(p_ent->elem.hdr.cid),