dmaengine: idxd: add RO check for wq max_batch_size write

[ 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>

diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 999ce13..f7ab5c0 100644 (file)
--- 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;