Add a read-only buffer_pools debugfs file that lists size, buff_size,
active, and available for every RX queue and buffer pool. That is the
MQ diagnostic view (multi-line table), which does not belong in sysfs.

Keep the historical queue-0 poolN sysfs ABI unchanged:

  .../poolN/{active,num,size}

Those are one-value-per-file *configuration* knobs for buffer-pool
classes on queue 0, not one directory per RX queue. With MQ, queue 0
pool geometry remains the shared template: open copies it to queues
1..N. Per-queue runtime pressure is what debugfs shows; this series
does not add per-queue pool sysfs dirs.

Unlike ibmvnic (one RX pool per RX queue, sized from firmware, almost
no pool sysfs), ibmveth historically has multiple size-class pools and
already exported poolN via sysfs. Moving only the new all-queue dump
to debugfs matches sysfs "one value per file" review feedback without
breaking that config ABI.

Path: /sys/kernel/debug/ibmveth/<dev_name>/buffer_pools
  (e.g. /sys/kernel/debug/ibmveth/30000002/buffer_pools)

Signed-off-by: Mingming Cao <[email protected]>
Reviewed-by: Dave Marquardt <[email protected]>
Tested-by: Shaik Abdulla <[email protected]>
---

Changes in v5:
- debugfs buffer_pools_show walks get_num_rx_queues()
- Series renumber: mailed v4 11/14 debugfs -> tip P13 (14->15)
- Path uses stable vio dev_name under a driver-owned root (not netdev
  name - avoids rename/collide)
- rtnl_lock around dump (writers are under RTNL)
- Show Active/Available as 0 when pool !live (debugfs view; free-path
  available clear already in the buffer-submit patch)

Changes in v4:
- Move the all-queue buffer_pools diagnostic from sysfs to debugfs;
  subject updated to match.
- Keep historical queue-0 poolN/{active,num,size} sysfs as one-value
  config (template for MQ); do not add per-queue pool sysfs dirs.

 drivers/net/ethernet/ibm/ibmveth.c | 69 ++++++++++++++++++++++++++++++
 drivers/net/ethernet/ibm/ibmveth.h |  2 +
 2 files changed, 71 insertions(+)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c 
b/drivers/net/ethernet/ibm/ibmveth.c
index 5d4ca4b3d3d0..1b58a3c6ce77 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -31,6 +31,7 @@
 #include <linux/ipv6.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/debugfs.h>
 #include <asm/hvcall.h>
 #include <linux/atomic.h>
 #include <asm/vio.h>
@@ -3421,6 +3422,68 @@ static const struct net_device_ops ibmveth_netdev_ops = {
 #endif
 };
 
+static int ibmveth_buffer_pools_show(struct seq_file *m, void *v)
+{
+       struct ibmveth_adapter *adapter = m->private;
+       int i, j;
+
+       /*
+        * Writers (veth_pool_store, open template copy, reset close/open)
+        * update these fields under RTNL. Take the same lock so the dump
+        * is not a torn scalar snapshot. Not required for
+        * memory safety ??? embedded arrays only.
+        */
+       rtnl_lock();
+
+       seq_puts(m, "Queue  Pool  Size  BuffSize  Active  Available\n");
+       seq_puts(m, "-----  ----  ----  --------  ------  ---------\n");
+       if (!adapter->opened)
+               seq_puts(m, "# down: Active/Available 0 unless allocated\n");
+
+       for (i = 0; i < ibmveth_get_num_rx_queues(adapter); i++) {
+               for (j = 0; j < IBMVETH_NUM_BUFF_POOLS; j++) {
+                       struct ibmveth_buff_pool *pool =
+                               &adapter->rx_buff_pool[i][j];
+                       bool live = pool->skbuff && pool->free_map;
+                       int active = live ? pool->active : 0;
+                       int available = live ? atomic_read(&pool->available)
+                                            : 0;
+
+                       seq_printf(m, "%5d  %4d  %4u  %8u  %6d  %9d\n",
+                                  i, j, pool->size, pool->buff_size,
+                                  active, available);
+               }
+       }
+
+       rtnl_unlock();
+       return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ibmveth_buffer_pools);
+
+/* Driver-owned root so per-adapter dirs use a stable vio name, not the
+ * mutable netdev->name (avoids stale names / eth0 collisions after rename).
+ */
+static struct dentry *ibmveth_dbg_root;
+
+static void ibmveth_debugfs_init(struct ibmveth_adapter *adapter)
+{
+       if (!ibmveth_dbg_root)
+               ibmveth_dbg_root =
+                       debugfs_create_dir(ibmveth_driver_name, NULL);
+
+       adapter->debugfs_dir =
+               debugfs_create_dir(dev_name(&adapter->vdev->dev),
+                                  ibmveth_dbg_root);
+       debugfs_create_file("buffer_pools", 0400, adapter->debugfs_dir,
+                           adapter, &ibmveth_buffer_pools_fops);
+}
+
+static void ibmveth_debugfs_exit(struct ibmveth_adapter *adapter)
+{
+       debugfs_remove_recursive(adapter->debugfs_dir);
+       adapter->debugfs_dir = NULL;
+}
+
 static void ibmveth_put_pool_kobjs(struct ibmveth_adapter *adapter,
                                   int pools_ready)
 {
@@ -3647,6 +3710,8 @@ static int ibmveth_probe(struct vio_dev *dev, const 
struct vio_device_id *id)
 
        netdev_dbg(netdev, "registered\n");
 
+       ibmveth_debugfs_init(adapter);
+
        return 0;
 }
 
@@ -3656,6 +3721,8 @@ static void ibmveth_remove(struct vio_dev *dev)
        struct ibmveth_adapter *adapter = netdev_priv(netdev);
        int i;
 
+       ibmveth_debugfs_exit(adapter);
+
        for (i = 0; i < IBMVETH_NUM_BUFF_POOLS; i++)
                kobject_put(&adapter->rx_buff_pool[0][i].kobj);
 
@@ -3891,6 +3958,8 @@ static int __init ibmveth_module_init(void)
 static void __exit ibmveth_module_exit(void)
 {
        vio_unregister_driver(&ibmveth_driver);
+       debugfs_remove_recursive(ibmveth_dbg_root);
+       ibmveth_dbg_root = NULL;
 }
 
 module_init(ibmveth_module_init);
diff --git a/drivers/net/ethernet/ibm/ibmveth.h 
b/drivers/net/ethernet/ibm/ibmveth.h
index 0960448f53ea..8c826d23ddf4 100644
--- a/drivers/net/ethernet/ibm/ibmveth.h
+++ b/drivers/net/ethernet/ibm/ibmveth.h
@@ -392,6 +392,8 @@ struct ibmveth_adapter {
        struct ibmveth_rx_queue_stats *rx_qstats;
        struct ibmveth_tx_queue_stats *tx_qstats;
 
+       struct dentry *debugfs_dir;
+
        /* Ethtool settings */
        u8 duplex;
        u32 speed;
-- 
2.50.1 (Apple Git-155)


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