From: Steve Wise <sw...@opengridcomputing.com>

For each p2pmem instance, add a "stats" file to show
the gen_pool statistics.

Signed-off-by: Steve Wise <sw...@opengridcomputing.com>
Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
Signed-off-by: Stephen Bates <sba...@raithlin.com>
---
 drivers/memory/p2pmem.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/p2pmem.h  |  2 ++
 2 files changed, 51 insertions(+)

diff --git a/drivers/memory/p2pmem.c b/drivers/memory/p2pmem.c
index c4ea311..71741c2 100644
--- a/drivers/memory/p2pmem.c
+++ b/drivers/memory/p2pmem.c
@@ -18,6 +18,7 @@
 #include <linux/slab.h>
 #include <linux/genalloc.h>
 #include <linux/memremap.h>
+#include <linux/debugfs.h>
 
 MODULE_DESCRIPTION("Peer 2 Peer Memory Device");
 MODULE_VERSION("0.1");
@@ -27,6 +28,40 @@ MODULE_AUTHOR("Microsemi Corporation");
 static struct class *p2pmem_class;
 static DEFINE_IDA(p2pmem_ida);
 
+static struct dentry *p2pmem_debugfs_root;
+
+static int stats_show(struct seq_file *seq, void *v)
+{
+       struct p2pmem_dev *p = seq->private;
+
+       if (p->pool) {
+               seq_printf(seq, "total size: %lu\n", gen_pool_size(p->pool));
+               seq_printf(seq, "available:  %lu\n", gen_pool_avail(p->pool));
+       }
+       return 0;
+}
+
+static int stats_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, stats_show, inode->i_private);
+}
+
+static const struct file_operations stats_debugfs_fops = {
+       .owner   = THIS_MODULE,
+       .open    = stats_open,
+       .release = single_release,
+       .read    = seq_read,
+       .llseek  = seq_lseek,
+};
+
+static void setup_debugfs(struct p2pmem_dev *p)
+{
+       struct dentry *de;
+
+       de = debugfs_create_file("stats", 0400, p->debugfs_root,
+                                (void *)p, &stats_debugfs_fops);
+}
+
 static struct p2pmem_dev *to_p2pmem(struct device *dev)
 {
        return container_of(dev, struct p2pmem_dev, dev);
@@ -62,6 +97,8 @@ static void p2pmem_release(struct device *dev)
 {
        struct p2pmem_dev *p = to_p2pmem(dev);
 
+       debugfs_remove_recursive(p->debugfs_root);
+
        if (p->pool)
                gen_pool_destroy(p->pool);
 
@@ -114,6 +151,13 @@ struct p2pmem_dev *p2pmem_create(struct device *parent)
        if (rc)
                goto err_id;
 
+       if (p2pmem_debugfs_root) {
+               p->debugfs_root = debugfs_create_dir(dev_name(&p->dev),
+                                                    p2pmem_debugfs_root);
+               if (p->debugfs_root)
+                       setup_debugfs(p);
+       }
+
        rc = device_add(&p->dev);
        if (rc)
                goto err_id;
@@ -390,12 +434,17 @@ static int __init p2pmem_init(void)
        if (IS_ERR(p2pmem_class))
                return PTR_ERR(p2pmem_class);
 
+       p2pmem_debugfs_root = debugfs_create_dir("p2pmem", NULL);
+       if (!p2pmem_debugfs_root)
+               pr_info("could not create debugfs entry, continuing\n");
+
        return 0;
 }
 module_init(p2pmem_init);
 
 static void __exit p2pmem_exit(void)
 {
+       debugfs_remove_recursive(p2pmem_debugfs_root);
        class_destroy(p2pmem_class);
 
        pr_info(KBUILD_MODNAME ": unloaded.\n");
diff --git a/include/linux/p2pmem.h b/include/linux/p2pmem.h
index 71dc1e1..4cd6f35 100644
--- a/include/linux/p2pmem.h
+++ b/include/linux/p2pmem.h
@@ -26,6 +26,8 @@ struct p2pmem_dev {
        struct percpu_ref ref;
        struct completion cmp;
        struct gen_pool *pool;
+
+       struct dentry *debugfs_root;
 };
 
 #ifdef CONFIG_P2PMEM
-- 
2.1.4

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