1 /* 2 * Hypervisor filesystem for Linux on s390 - debugfs interface 3 * 4 * Copyright IBM Corp. 2010 5 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com> 6 */ 7 8 #include <linux/slab.h> 9 #include "hypfs.h" 10 11 static struct dentry *dbfs_dir; 12 13 static struct hypfs_dbfs_data *hypfs_dbfs_data_alloc(struct hypfs_dbfs_file *f) 14 { 15 struct hypfs_dbfs_data *data; 16 17 data = kmalloc(sizeof(*data), GFP_KERNEL); 18 if (!data) 19 return NULL; 20 data->dbfs_file = f; 21 return data; 22 } 23 24 static void hypfs_dbfs_data_free(struct hypfs_dbfs_data *data) 25 { 26 data->dbfs_file->data_free(data->buf_free_ptr); 27 kfree(data); 28 } 29 30 static ssize_t dbfs_read(struct file *file, char __user *buf, 31 size_t size, loff_t *ppos) 32 { 33 struct hypfs_dbfs_data *data; 34 struct hypfs_dbfs_file *df; 35 ssize_t rc; 36 37 if (*ppos != 0) 38 return 0; 39 40 df = file_inode(file)->i_private; 41 mutex_lock(&df->lock); 42 data = hypfs_dbfs_data_alloc(df); 43 if (!data) { 44 mutex_unlock(&df->lock); 45 return -ENOMEM; 46 } 47 rc = df->data_create(&data->buf, &data->buf_free_ptr, &data->size); 48 if (rc) { 49 mutex_unlock(&df->lock); 50 kfree(data); 51 return rc; 52 } 53 mutex_unlock(&df->lock); 54 55 rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size); 56 hypfs_dbfs_data_free(data); 57 return rc; 58 } 59 60 static long dbfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 61 { 62 struct hypfs_dbfs_file *df = file_inode(file)->i_private; 63 long rc; 64 65 mutex_lock(&df->lock); 66 if (df->unlocked_ioctl) 67 rc = df->unlocked_ioctl(file, cmd, arg); 68 else 69 rc = -ENOTTY; 70 mutex_unlock(&df->lock); 71 return rc; 72 } 73 74 static const struct file_operations dbfs_ops = { 75 .read = dbfs_read, 76 .llseek = no_llseek, 77 .unlocked_ioctl = dbfs_ioctl, 78 }; 79 80 int hypfs_dbfs_create_file(struct hypfs_dbfs_file *df) 81 { 82 df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df, 83 &dbfs_ops); 84 if (IS_ERR(df->dentry)) 85 return PTR_ERR(df->dentry); 86 mutex_init(&df->lock); 87 return 0; 88 } 89 90 void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df) 91 { 92 debugfs_remove(df->dentry); 93 } 94 95 int hypfs_dbfs_init(void) 96 { 97 dbfs_dir = debugfs_create_dir("s390_hypfs", NULL); 98 return PTR_ERR_OR_ZERO(dbfs_dir); 99 } 100 101 void hypfs_dbfs_exit(void) 102 { 103 debugfs_remove(dbfs_dir); 104 } 105