[tip:ras/core] RAS/CEC: Do not set decay value on error

[tip-bot for Borislav Petkov]

Commit-ID:  5cc6b16ea1313d05956b55e83a1f753c604282a8
Gitweb:     https://git.kernel.org/tip/5cc6b16ea1313d05956b55e83a1f753c604282a8
Author:     Borislav Petkov <bp@xxxxxxx>
AuthorDate: Sat, 20 Apr 2019 21:33:08 +0200
Committer:  Borislav Petkov <bp@xxxxxxx>
CommitDate: Sat, 8 Jun 2019 17:34:36 +0200

RAS/CEC: Do not set decay value on error

When the value requested doesn't match the allowed (min,max) range,
the @data buffer should not be modified with the invalid value because
reading "decay_interval" shows it otherwise as if the previous write
succeeded.

Move the data write after the check.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: linux-edac <linux-edac@xxxxxxxxxxxxxxx>
---
 drivers/ras/cec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index 73a975c26f9f..31868bd99e8d 100644
--- a/drivers/ras/cec.c
+++ b/drivers/ras/cec.c
@@ -371,17 +371,17 @@ DEFINE_DEBUGFS_ATTRIBUTE(pfn_ops, u64_get, pfn_set, "0x%llx\n");
 
 static int decay_interval_set(void *data, u64 val)
 {
-	*(u64 *)data = val;
-
 	if (val < CEC_DECAY_MIN_INTERVAL)
 		return -EINVAL;
 
 	if (val > CEC_DECAY_MAX_INTERVAL)
 		return -EINVAL;
 
+	*(u64 *)data   = val;
 	decay_interval = val;
 
 	cec_mod_work(decay_interval);
+
 	return 0;
 }
 DEFINE_DEBUGFS_ATTRIBUTE(decay_interval_ops, u64_get, decay_interval_set, "%lld\n");