dmaengine: idxd: Fix default allowed read buffers value in group

Currently default read buffers that is allowed in a group is 0.
grpcfg will be configured to max read buffers that IDXD can support if
the group's allowed read buffers value is 0. But 0 is an invalid
read buffers value and user may get confused when seeing the invalid
initial value 0 through sysfs interface.

To show only valid allowed read buffers value and eliminate confusion,
directly initialize the allowed read buffers to IDXD's max read buffers.
User still can change the value through sysfs interface.

Suggested-by: Ramesh Thomas <[email protected]>
Signed-off-by: Fenghua Yu <[email protected]>
Reviewed-by: Nikhil Rao <[email protected]>
Reviewed-by: Dave Jiang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: Fenghua Yu

drivers/dma/idxd/device.c

@@ -699,7 +699,11 @@ static void idxd_groups_clear_state(struct idxd_device *idxd)
 		group->num_engines = 0;
 		group->num_wqs = 0;
 		group->use_rdbuf_limit = false;
-		group->rdbufs_allowed = 0;
+		/*
+		 * The default value is the same as the value of
+		 * total read buffers in GRPCAP.
+		 */
+		group->rdbufs_allowed = idxd->max_rdbufs;
 		group->rdbufs_reserved = 0;
 		if (idxd->hw.version <= DEVICE_VERSION_2 && !tc_override) {
 			group->tc_a = 1;
@@ -934,11 +938,7 @@ static void idxd_group_flags_setup(struct idxd_device *idxd)
 			group->grpcfg.flags.tc_b = group->tc_b;
 		group->grpcfg.flags.use_rdbuf_limit = group->use_rdbuf_limit;
 		group->grpcfg.flags.rdbufs_reserved = group->rdbufs_reserved;
-		if (group->rdbufs_allowed)
-			group->grpcfg.flags.rdbufs_allowed = group->rdbufs_allowed;
-		else
-			group->grpcfg.flags.rdbufs_allowed = idxd->max_rdbufs;
-
+		group->grpcfg.flags.rdbufs_allowed = group->rdbufs_allowed;
 		group->grpcfg.flags.desc_progress_limit = group->desc_progress_limit;
 		group->grpcfg.flags.batch_progress_limit = group->batch_progress_limit;
 	}

drivers/dma/idxd/init.c

@@ -302,6 +302,11 @@ static int idxd_setup_groups(struct idxd_device *idxd)
 			group->tc_a = -1;
 			group->tc_b = -1;
 		}
+		/*
+		 * The default value is the same as the value of
+		 * total read buffers in GRPCAP.
+		 */
+		group->rdbufs_allowed = idxd->max_rdbufs;
 	}
 
 	return 0;