[PATCH 5.15 049/124] dmaengine: idxd: add RO check for wq max_transfer_size write

[Greg Kroah-Hartman]

From: Dave Jiang <dave.jiang@xxxxxxxxx>

[ Upstream commit 505a2d1032ae656b0a8c736be110255503941cde ]

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

Fixes: d7aad5550eca ("dmaengine: idxd: add support for configurable max wq xfer size")
Reported-by: Bernice Zhang <bernice.zhang@xxxxxxxxx>
Tested-by: Bernice Zhang <bernice.zhang@xxxxxxxxx>
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Link: https://lore.kernel.org/r/164971488154.2200913.10706665404118545941.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 f7ab5c077a2b..33d94c67fedb 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -842,6 +842,9 @@ static ssize_t wq_max_transfer_size_store(struct device *dev, struct device_attr
 	u64 xfer_size;
 	int rc;
 
+	if (!test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
+		return -EPERM;
+
 	if (wq->state != IDXD_WQ_DISABLED)
 		return -EPERM;
 
-- 
2.35.1