6 files changed, 195 insertions, 118 deletions

diff --git a/arch/s390/hypfs/Makefile b/arch/s390/hypfs/Makefile
index b08d2ab..2e671d5 100644
--- a/arch/s390/hypfs/Makefile
+++ b/arch/s390/hypfs/Makefile
@@ -4,4 +4,4 @@
 
 obj-$(CONFIG_S390_HYPFS_FS) += s390_hypfs.o
 
-s390_hypfs-objs := inode.o hypfs_diag.o hypfs_vm.o
+s390_hypfs-objs := inode.o hypfs_diag.o hypfs_vm.o hypfs_dbfs.o
diff --git a/arch/s390/hypfs/hypfs.h b/arch/s390/hypfs/hypfs.h
index fa487d4..80c1526 100644
--- a/arch/s390/hypfs/hypfs.h
+++ b/arch/s390/hypfs/hypfs.h
@@ -12,6 +12,8 @@
 #include <linux/fs.h>
 #include <linux/types.h>
 #include <linux/debugfs.h>
+#include <linux/workqueue.h>
+#include <linux/kref.h>
 
 #define REG_FILE_MODE    0440
 #define UPDATE_FILE_MODE 0220
@@ -38,6 +40,33 @@ extern int hypfs_vm_init(void);
 extern void hypfs_vm_exit(void);
 extern int hypfs_vm_create_files(struct super_block *sb, struct dentry *root);
 
-/* Directory for debugfs files */
-extern struct dentry *hypfs_dbfs_dir;
+/* debugfs interface */
+struct hypfs_dbfs_file;
+
+struct hypfs_dbfs_data {
+	void			*buf;
+	void			*buf_free_ptr;
+	size_t			size;
+	struct hypfs_dbfs_file	*dbfs_file;;
+	struct kref		kref;
+};
+
+struct hypfs_dbfs_file {
+	const char	*name;
+	int		(*data_create)(void **data, void **data_free_ptr,
+				       size_t *size);
+	void		(*data_free)(const void *buf_free_ptr);
+
+	/* Private data for hypfs_dbfs.c */
+	struct hypfs_dbfs_data	*data;
+	struct delayed_work	data_free_work;
+	struct mutex		lock;
+	struct dentry		*dentry;
+};
+
+extern int hypfs_dbfs_init(void);
+extern void hypfs_dbfs_exit(void);
+extern int hypfs_dbfs_create_file(struct hypfs_dbfs_file *df);
+extern void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df);
+
 #endif /* _HYPFS_H_ */
diff --git a/arch/s390/hypfs/hypfs_dbfs.c b/arch/s390/hypfs/hypfs_dbfs.c
new file mode 100644
index 0000000..b478013
--- /dev/null
+++ b/arch/s390/hypfs/hypfs_dbfs.c
@@ -0,0 +1,116 @@
+/*
+ * Hypervisor filesystem for Linux on s390 - debugfs interface
+ *
+ * Copyright (C) IBM Corp. 2010
+ * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
+ */
+
+#include <linux/slab.h>
+#include "hypfs.h"
+
+static struct dentry *dbfs_dir;
+
+static struct hypfs_dbfs_data *hypfs_dbfs_data_alloc(struct hypfs_dbfs_file *f)
+{
+	struct hypfs_dbfs_data *data;
+
+	data = kmalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return NULL;
+	kref_init(&data->kref);
+	data->dbfs_file = f;
+	return data;
+}
+
+static void hypfs_dbfs_data_free(struct kref *kref)
+{
+	struct hypfs_dbfs_data *data;
+
+	data = container_of(kref, struct hypfs_dbfs_data, kref);
+	data->dbfs_file->data_free(data->buf_free_ptr);
+	kfree(data);
+}
+
+static void data_free_delayed(struct work_struct *work)
+{
+	struct hypfs_dbfs_data *data;
+	struct hypfs_dbfs_file *df;
+
+	df = container_of(work, struct hypfs_dbfs_file, data_free_work.work);
+	mutex_lock(&df->lock);
+	data = df->data;
+	df->data = NULL;
+	mutex_unlock(&df->lock);
+	kref_put(&data->kref, hypfs_dbfs_data_free);
+}
+
+static ssize_t dbfs_read(struct file *file, char __user *buf,
+			 size_t size, loff_t *ppos)
+{
+	struct hypfs_dbfs_data *data;
+	struct hypfs_dbfs_file *df;
+	ssize_t rc;
+
+	if (*ppos != 0)
+		return 0;
+
+	df = file->f_path.dentry->d_inode->i_private;
+	mutex_lock(&df->lock);
+	if (!df->data) {
+		data = hypfs_dbfs_data_alloc(df);
+		if (!data) {
+			mutex_unlock(&df->lock);
+			return -ENOMEM;
+		}
+		rc = df->data_create(&data->buf, &data->buf_free_ptr,
+				     &data->size);
+		if (rc) {
+			mutex_unlock(&df->lock);
+			kfree(data);
+			return rc;
+		}
+		df->data = data;
+		schedule_delayed_work(&df->data_free_work, HZ);
+	}
+	data = df->data;
+	kref_get(&data->kref);
+	mutex_unlock(&df->lock);
+
+	rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size);
+	kref_put(&data->kref, hypfs_dbfs_data_free);
+	return rc;
+}
+
+static const struct file_operations dbfs_ops = {
+	.read		= dbfs_read,
+	.llseek		= no_llseek,
+};
+
+int hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
+{
+	df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df,
+					 &dbfs_ops);
+	if (IS_ERR(df->dentry))
+		return PTR_ERR(df->dentry);
+	mutex_init(&df->lock);
+	INIT_DELAYED_WORK(&df->data_free_work, data_free_delayed);
+	return 0;
+}
+
+void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
+{
+	debugfs_remove(df->dentry);
+}
+
+int hypfs_dbfs_init(void)
+{
+	dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
+	if (IS_ERR(dbfs_dir))
+		return PTR_ERR(dbfs_dir);
+	return 0;
+}
+
+void hypfs_dbfs_exit(void)
+{
+	debugfs_remove(dbfs_dir);
+}
diff --git a/arch/s390/hypfs/hypfs_diag.c b/arch/s390/hypfs/hypfs_diag.c
index cd4a81b..6023c6d 100644
--- a/arch/s390/hypfs/hypfs_diag.c
+++ b/arch/s390/hypfs/hypfs_diag.c
@@ -555,81 +555,38 @@ struct dbfs_d204 {
 	char			buf[];	/* d204 buffer */
 } __attribute__ ((packed));
 
-struct dbfs_d204_private {
-	struct dbfs_d204	*d204;	/* Aligned d204 data with header */
-	void			*base;	/* Base pointer (needed for vfree) */
-};
-
-static int dbfs_d204_open(struct inode *inode, struct file *file)
+static int dbfs_d204_create(void **data, void **data_free_ptr, size_t *size)
 {
-	struct dbfs_d204_private *data;
 	struct dbfs_d204 *d204;
 	int rc, buf_size;
+	void *base;
 
-	data = kzalloc(sizeof(*data), GFP_KERNEL);
-	if (!data)
-		return -ENOMEM;
 	buf_size = PAGE_SIZE * (diag204_buf_pages + 1) + sizeof(d204->hdr);
-	data->base = vmalloc(buf_size);
-	if (!data->base) {
-		rc = -ENOMEM;
-		goto fail_kfree_data;
+	base = vmalloc(buf_size);
+	if (!base)
+		return -ENOMEM;
+	memset(base, 0, buf_size);
+	d204 = page_align_ptr(base + sizeof(d204->hdr)) - sizeof(d204->hdr);
+	rc = diag204_do_store(d204->buf, diag204_buf_pages);
+	if (rc) {
+		vfree(base);
+		return rc;
 	}
-	memset(data->base, 0, buf_size);
-	d204 = page_align_ptr(data->base + sizeof(d204->hdr))
-		- sizeof(d204->hdr);
-	rc = diag204_do_store(&d204->buf, diag204_buf_pages);
-	if (rc)
-		goto fail_vfree_base;
 	d204->hdr.version = DBFS_D204_HDR_VERSION;
 	d204->hdr.len = PAGE_SIZE * diag204_buf_pages;
 	d204->hdr.sc = diag204_store_sc;
-	data->d204 = d204;
-	file->private_data = data;
-	return nonseekable_open(inode, file);
-
-fail_vfree_base:
-	vfree(data->base);
-fail_kfree_data:
-	kfree(data);
-	return rc;
-}
-
-static int dbfs_d204_release(struct inode *inode, struct file *file)
-{
-	struct dbfs_d204_private *data = file->private_data;
-
-	vfree(data->base);
-	kfree(data);
+	*data = d204;
+	*data_free_ptr = base;
+	*size = d204->hdr.len + sizeof(struct dbfs_d204_hdr);
 	return 0;
 }
 
-static ssize_t dbfs_d204_read(struct file *file, char __user *buf,
-			      size_t size, loff_t *ppos)
-{
-	struct dbfs_d204_private *data = file->private_data;
-
-	return simple_read_from_buffer(buf, size, ppos, data->d204,
-				       data->d204->hdr.len +
-				       sizeof(data->d204->hdr));
-}
-
-static const struct file_operations dbfs_d204_ops = {
-	.open		= dbfs_d204_open,
-	.read		= dbfs_d204_read,
-	.release	= dbfs_d204_release,
-	.llseek		= no_llseek,
+static struct hypfs_dbfs_file dbfs_file_d204 = {
+	.name		= "diag_204",
+	.data_create	= dbfs_d204_create,
+	.data_free	= vfree,
 };
 
-static int hypfs_dbfs_init(void)
-{
-	dbfs_d204_file = debugfs_create_file("diag_204", 0400, hypfs_dbfs_dir,
-					     NULL, &dbfs_d204_ops);
-	if (IS_ERR(dbfs_d204_file))
-		return PTR_ERR(dbfs_d204_file);
-	return 0;
-}
-
 __init int hypfs_diag_init(void)
 {
 	int rc;
@@ -639,7 +596,7 @@ __init int hypfs_diag_init(void)
 		return -ENODATA;
 	}
 	if (diag204_info_type == INFO_EXT) {
-		rc = hypfs_dbfs_init();
+		rc = hypfs_dbfs_create_file(&dbfs_file_d204);
 		if (rc)
 			return rc;
 	}
@@ -660,6 +617,7 @@ void hypfs_diag_exit(void)
 	debugfs_remove(dbfs_d204_file);
 	diag224_delete_name_table();
 	diag204_free_buffer();
+	hypfs_dbfs_remove_file(&dbfs_file_d204);
 }
 
 /*
diff --git a/arch/s390/hypfs/hypfs_vm.c b/arch/s390/hypfs/hypfs_vm.c
index 26cf177..e547960 100644
--- a/arch/s390/hypfs/hypfs_vm.c
+++ b/arch/s390/hypfs/hypfs_vm.c
@@ -20,8 +20,6 @@ static char local_guest[] = "        ";
 static char all_guests[] = "*       ";
 static char *guest_query;
 
-static struct dentry *dbfs_d2fc_file;
-
 struct diag2fc_data {
 	__u32 version;
 	__u32 flags;
@@ -104,7 +102,7 @@ static void *diag2fc_store(char *query, unsigned int *count, int offset)
 	return data;
 }
 
-static void diag2fc_free(void *data)
+static void diag2fc_free(const void *data)
 {
 	vfree(data);
 }
@@ -239,43 +237,29 @@ struct dbfs_d2fc {
 	char			buf[];	/* d2fc buffer */
 } __attribute__ ((packed));
 
-static int dbfs_d2fc_open(struct inode *inode, struct file *file)
+static int dbfs_diag2fc_create(void **data, void **data_free_ptr, size_t *size)
 {
-	struct dbfs_d2fc *data;
+	struct dbfs_d2fc *d2fc;
 	unsigned int count;
 
-	data = diag2fc_store(guest_query, &count, sizeof(data->hdr));
-	if (IS_ERR(data))
-		return PTR_ERR(data);
-	get_clock_ext(data->hdr.tod_ext);
-	data->hdr.len = count * sizeof(struct diag2fc_data);
-	data->hdr.version = DBFS_D2FC_HDR_VERSION;
-	data->hdr.count = count;
-	memset(&data->hdr.reserved, 0, sizeof(data->hdr.reserved));
-	file->private_data = data;
-	return nonseekable_open(inode, file);
-}
-
-static int dbfs_d2fc_release(struct inode *inode, struct file *file)
-{
-	diag2fc_free(file->private_data);
+	d2fc = diag2fc_store(guest_query, &count, sizeof(d2fc->hdr));
+	if (IS_ERR(d2fc))
+		return PTR_ERR(d2fc);
+	get_clock_ext(d2fc->hdr.tod_ext);
+	d2fc->hdr.len = count * sizeof(struct diag2fc_data);
+	d2fc->hdr.version = DBFS_D2FC_HDR_VERSION;
+	d2fc->hdr.count = count;
+	memset(&d2fc->hdr.reserved, 0, sizeof(d2fc->hdr.reserved));
+	*data = d2fc;
+	*data_free_ptr = d2fc;
+	*size = d2fc->hdr.len + sizeof(struct dbfs_d2fc_hdr);
 	return 0;
 }
 
-static ssize_t dbfs_d2fc_read(struct file *file, char __user *buf,
-				    size_t size, loff_t *ppos)
-{
-	struct dbfs_d2fc *data = file->private_data;
-
-	return simple_read_from_buffer(buf, size, ppos, data, data->hdr.len +
-				       sizeof(struct dbfs_d2fc_hdr));
-}
-
-static const struct file_operations dbfs_d2fc_ops = {
-	.open		= dbfs_d2fc_open,
-	.read		= dbfs_d2fc_read,
-	.release	= dbfs_d2fc_release,
-	.llseek		= no_llseek,
+static struct hypfs_dbfs_file dbfs_file_2fc = {
+	.name		= "diag_2fc",
+	.data_create	= dbfs_diag2fc_create,
+	.data_free	= diag2fc_free,
 };
 
 int hypfs_vm_init(void)
@@ -288,18 +272,12 @@ int hypfs_vm_init(void)
 		guest_query = local_guest;
 	else
 		return -EACCES;
-
-	dbfs_d2fc_file = debugfs_create_file("diag_2fc", 0400, hypfs_dbfs_dir,
-					     NULL, &dbfs_d2fc_ops);
-	if (IS_ERR(dbfs_d2fc_file))
-		return PTR_ERR(dbfs_d2fc_file);
-
-	return 0;
+	return hypfs_dbfs_create_file(&dbfs_file_2fc);
 }
 
 void hypfs_vm_exit(void)
 {
 	if (!MACHINE_IS_VM)
 		return;
-	debugfs_remove(dbfs_d2fc_file);
+	hypfs_dbfs_remove_file(&dbfs_file_2fc);
 }
diff --git a/arch/s390/hypfs/inode.c b/arch/s390/hypfs/inode.c
index 47cc446..6fe874f 100644
--- a/arch/s390/hypfs/inode.c
+++ b/arch/s390/hypfs/inode.c
@@ -46,8 +46,6 @@ static const struct super_operations hypfs_s_ops;
 /* start of list of all dentries, which have to be deleted on update */
 static struct dentry *hypfs_last_dentry;
 
-struct dentry *hypfs_dbfs_dir;
-
 static void hypfs_update_update(struct super_block *sb)
 {
 	struct hypfs_sb_info *sb_info = sb->s_fs_info;
@@ -471,13 +469,12 @@ static int __init hypfs_init(void)
 {
 	int rc;
 
-	hypfs_dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
-	if (IS_ERR(hypfs_dbfs_dir))
-		return PTR_ERR(hypfs_dbfs_dir);
-
+	rc = hypfs_dbfs_init();
+	if (rc)
+		return rc;
 	if (hypfs_diag_init()) {
 		rc = -ENODATA;
-		goto fail_debugfs_remove;
+		goto fail_dbfs_exit;
 	}
 	if (hypfs_vm_init()) {
 		rc = -ENODATA;
@@ -499,9 +496,8 @@ fail_hypfs_vm_exit:
 	hypfs_vm_exit();
 fail_hypfs_diag_exit:
 	hypfs_diag_exit();
-fail_debugfs_remove:
-	debugfs_remove(hypfs_dbfs_dir);
-
+fail_dbfs_exit:
+	hypfs_dbfs_exit();
 	pr_err("Initialization of hypfs failed with rc=%i\n", rc);
 	return rc;
 }
@@ -510,7 +506,7 @@ static void __exit hypfs_exit(void)
 {
 	hypfs_diag_exit();
 	hypfs_vm_exit();
-	debugfs_remove(hypfs_dbfs_dir);
+	hypfs_dbfs_exit();
 	unregister_filesystem(&hypfs_type);
 	kobject_put(s390_kobj);
 }