The OPAL NVRAM driver does not sleep in case it gets OPAL_BUSY or
OPAL_BUSY_EVENT from firmware, which causes large scheduling
latencies, and various lockup errors to trigger (again, BMC reboot
can cause it).
Fix this by converting it to the standard form OPAL_BUSY loop that
sleeps.
Fixes: 628daa8d5abfd ("powerpc/powernv: Add RTC and NVRAM support plus RTAS
fallbacks")
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/platforms/powernv/opal-nvram.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/opal-nvram.c
b/arch/powerpc/platforms/powernv/opal-nvram.c
index ba2ff06a2c98..1bceb95f422d 100644
--- a/arch/powerpc/platforms/powernv/opal-nvram.c
+++ b/arch/powerpc/platforms/powernv/opal-nvram.c
@@ -11,6 +11,7 @@
#define DEBUG
+#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/of.h>
@@ -56,8 +57,12 @@ static ssize_t opal_nvram_write(char *buf, size_t count,
loff_t *index)
while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
rc = opal_write_nvram(__pa(buf), count, off);
- if (rc == OPAL_BUSY_EVENT)
+ if (rc == OPAL_BUSY_EVENT) {
+ msleep(OPAL_BUSY_DELAY_MS);
opal_poll_events(NULL);
+ } else if (rc == OPAL_BUSY) {
+ msleep(OPAL_BUSY_DELAY_MS);
+ }
}
if (rc)
--
2.17.0
