From 2d0b1919457ad78036f24169968cadc6f55d37ec Mon Sep 17 00:00:00 2001
From: Dave Jiang <dave.jiang@intel.com>
Date: Tue, 18 Feb 2020 09:51:58 -0700
Subject: [PATCH] dmaengine: idxd: correct reserved token calculation
Git-commit: 2d0b1919457ad78036f24169968cadc6f55d37ec
Patch-mainline: v5.6-rc5
References: jsc#SLE-12688

The calcuation for limit of reserved token did not take into account the
change the user wanted vs the current group reserved token. This causes
changing of the reserved token to be possible only after we set the value
of the reserved token back to 0. Fix calculation so we can set a value that
is non zero for reserved token.

Fixes: c52ca478233c ("dmaengine: idxd: add configuration component of driver")
Reported-by: Jerry Chen <jerry.t.chen@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/158204471889.37789.7749177228265869168.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/dma/idxd/sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 298855ca934f..edbfe83325eb 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -519,7 +519,7 @@ static ssize_t group_tokens_reserved_store(struct device *dev,
 	if (val > idxd->max_tokens)
 		return -EINVAL;
 
-	if (val > idxd->nr_tokens)
+	if (val > idxd->nr_tokens + group->tokens_reserved)
 		return -EINVAL;
 
 	group->tokens_reserved = val;
-- 
2.16.4