releases/4.4.259/powerpc-pseries-dlpar-handle-ibm-configure-connector.patch

From c055ba982bbecb8359e8c5c15e1859241546ff79 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Wed, 6 Jan 2021 20:59:00 -0600
Subject: powerpc/pseries/dlpar: handle ibm, configure-connector delay status

From: Nathan Lynch <nathanl@linux.ibm.com>

[ Upstream commit 768d70e19ba525debd571b36e6d0ab19956c63d7 ]

dlpar_configure_connector() has two problems in its handling of
ibm,configure-connector's return status:

1. When the status is -2 (busy, call again), we call
   ibm,configure-connector again immediately without checking whether
   to schedule, which can result in monopolizing the CPU.
2. Extended delay status (9900..9905) goes completely unhandled,
   causing the configuration to unnecessarily terminate.

Fix both of these issues by using rtas_busy_delay().

Fixes: ab519a011caa ("powerpc/pseries: Kernel DLPAR Infrastructure")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210107025900.410369-1-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/pseries/dlpar.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
index 551ba5b35df9d..91a667d8b1e90 100644
--- a/arch/powerpc/platforms/pseries/dlpar.c
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -131,7 +131,6 @@ void dlpar_free_cc_nodes(struct device_node *dn)
 #define NEXT_PROPERTY   3
 #define PREV_PARENT     4
 #define MORE_MEMORY     5
-#define CALL_AGAIN	-2
 #define ERR_CFG_USE     -9003
 
 struct device_node *dlpar_configure_connector(__be32 drc_index,
@@ -173,6 +172,9 @@ struct device_node *dlpar_configure_connector(__be32 drc_index,
 
 		spin_unlock(&rtas_data_buf_lock);
 
+		if (rtas_busy_delay(rc))
+			continue;
+
 		switch (rc) {
 		case COMPLETE:
 			break;
@@ -225,9 +227,6 @@ struct device_node *dlpar_configure_connector(__be32 drc_index,
 			parent_path = last_dn->parent->full_name;
 			break;
 
-		case CALL_AGAIN:
-			break;
-
 		case MORE_MEMORY:
 		case ERR_CFG_USE:
 		default:
-- 
2.27.0