linux-kernel - [PATCH] dmaengine: idxd: Fix default allowed read buffers value in group

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Date:   Fri, 27 Jan 2023 11:28:55 -0800
From:   Fenghua Yu <fenghua.yu@...el.com>
To:     "Vinod Koul" <vkoul@...nel.org>,
        "Dave Jiang" <dave.jiang@...el.com>
Cc:     "linux-kernel" <linux-kernel@...r.kernel.org>,
        dmaengine@...r.kernel.org, Fenghua Yu <fenghua.yu@...el.com>,
        Ramesh Thomas <ramesh.thomas@...el.com>,
        Nikhil Rao <nikhil.rao@...el.com>
Subject: [PATCH] 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 <ramesh.thomas@...el.com>
Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
Reviewed-by: Nikhil Rao <nikhil.rao@...el.com>
---
 drivers/dma/idxd/device.c | 12 ++++++------
 drivers/dma/idxd/init.c   |  5 +++++
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 29dbb0f52e18..8d0e3aab2ad2 100644
--- a/drivers/dma/idxd/device.c
+++ b/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;
 	}
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 529ea09c9094..b2df604e8a5f 100644
--- a/drivers/dma/idxd/init.c
+++ b/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;
-- 
2.32.0