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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Bernice Zhang <bernice.zhang@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Vinod Koul <vkoul@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 048/124] dmaengine: idxd: add RO check for wq max_batch_size write
Date:   Tue, 26 Apr 2022 10:20:49 +0200
Message-Id: <20220426081748.667036725@linuxfoundation.org>
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From: Dave Jiang <dave.jiang@intel.com>

[ Upstream commit 66903461ffed0b66fc3e0200082d4e09365aacdc ]

Block wq_max_batch_size_store() when the device is configured as read-only
and not configurable.

Fixes: e7184b159dd3 ("dmaengine: idxd: add support for configurable max wq batch size")
Reported-by: Bernice Zhang <bernice.zhang@intel.com>
Tested-by: Bernice Zhang <bernice.zhang@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/164971493551.2201159.1942042593642155209.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/dma/idxd/sysfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 999ce13a93ad..f7ab5c077a2b 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -876,6 +876,9 @@ static ssize_t wq_max_batch_size_store(struct device *dev, struct device_attribu
 	u64 batch_size;
 	int rc;
 
+	if (!test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
+		return -EPERM;
+
 	if (wq->state != IDXD_WQ_DISABLED)
 		return -EPERM;
 
-- 
2.35.1