dmaengine: idxd: add RO check for wq max_transfer_size write

[ 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@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/164971488154.2200913.10706665404118545941.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index f7ab5c077a2b927d8b2a02ecef3647618c4c08f9..33d94c67fedb9fdecf5edfec593e1e34eb9a5610 100644 (file)
--- 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;