a178220df3
Currently the binary hypfs interfaces provides new data only once within an interval time of one second. This patch removes this restriction and now new data is returned immediately on every read on a hypfs binary file. This is done in order to allow more consistent snapshots for programs that read multiple hypfs binary files. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
105 lines
2.1 KiB
C
105 lines
2.1 KiB
C
/*
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* Hypervisor filesystem for Linux on s390 - debugfs interface
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*
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* Copyright IBM Corp. 2010
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* Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
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*/
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#include <linux/slab.h>
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#include "hypfs.h"
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static struct dentry *dbfs_dir;
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static struct hypfs_dbfs_data *hypfs_dbfs_data_alloc(struct hypfs_dbfs_file *f)
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{
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struct hypfs_dbfs_data *data;
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data = kmalloc(sizeof(*data), GFP_KERNEL);
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if (!data)
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return NULL;
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data->dbfs_file = f;
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return data;
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}
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static void hypfs_dbfs_data_free(struct hypfs_dbfs_data *data)
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{
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data->dbfs_file->data_free(data->buf_free_ptr);
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kfree(data);
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}
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static ssize_t dbfs_read(struct file *file, char __user *buf,
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size_t size, loff_t *ppos)
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{
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struct hypfs_dbfs_data *data;
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struct hypfs_dbfs_file *df;
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ssize_t rc;
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if (*ppos != 0)
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return 0;
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df = file_inode(file)->i_private;
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mutex_lock(&df->lock);
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data = hypfs_dbfs_data_alloc(df);
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if (!data) {
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mutex_unlock(&df->lock);
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return -ENOMEM;
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}
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rc = df->data_create(&data->buf, &data->buf_free_ptr, &data->size);
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if (rc) {
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mutex_unlock(&df->lock);
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kfree(data);
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return rc;
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}
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mutex_unlock(&df->lock);
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rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size);
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hypfs_dbfs_data_free(data);
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return rc;
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}
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static long dbfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct hypfs_dbfs_file *df = file_inode(file)->i_private;
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long rc;
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mutex_lock(&df->lock);
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if (df->unlocked_ioctl)
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rc = df->unlocked_ioctl(file, cmd, arg);
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else
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rc = -ENOTTY;
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mutex_unlock(&df->lock);
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return rc;
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}
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static const struct file_operations dbfs_ops = {
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.read = dbfs_read,
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.llseek = no_llseek,
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.unlocked_ioctl = dbfs_ioctl,
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};
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int hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
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{
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df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df,
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&dbfs_ops);
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if (IS_ERR(df->dentry))
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return PTR_ERR(df->dentry);
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mutex_init(&df->lock);
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return 0;
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}
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void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
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{
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debugfs_remove(df->dentry);
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}
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int hypfs_dbfs_init(void)
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{
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dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
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return PTR_ERR_OR_ZERO(dbfs_dir);
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}
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void hypfs_dbfs_exit(void)
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{
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debugfs_remove(dbfs_dir);
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}
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