Import of Linus's Linux 1.1.68

1 files changed, 276 insertions, 0 deletions

diff --git a/fs/devices.c b/fs/devices.c
new file mode 100644
index 000000000..e79ea07d5
--- /dev/null
+++ b/fs/devices.c
@@ -0,0 +1,276 @@
+/*
+ *  linux/fs/devices.c
+ *
+ * (C) 1993 Matthias Urlichs -- collected common code and tables.
+ * 
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/fs.h>
+#include <linux/major.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+#include <linux/ext_fs.h>
+#include <linux/stat.h>
+#include <linux/fcntl.h>
+#include <linux/errno.h>
+
+struct device_struct {
+	const char * name;
+	struct file_operations * fops;
+};
+
+static struct device_struct chrdevs[MAX_CHRDEV] = {
+	{ NULL, NULL },
+};
+
+static struct device_struct blkdevs[MAX_BLKDEV] = {
+	{ NULL, NULL },
+};
+
+int get_device_list(char * page)
+{
+	int i;
+	int len;
+
+	len = sprintf(page, "Character devices:\n");
+	for (i = 0; i < MAX_CHRDEV ; i++) {
+		if (chrdevs[i].fops) {
+			len += sprintf(page+len, "%2d %s\n", i, chrdevs[i].name);
+		}
+	}
+	len += sprintf(page+len, "\nBlock devices:\n");
+	for (i = 0; i < MAX_BLKDEV ; i++) {
+		if (blkdevs[i].fops) {
+			len += sprintf(page+len, "%2d %s\n", i, blkdevs[i].name);
+		}
+	}
+	return len;
+}
+
+struct file_operations * get_blkfops(unsigned int major)
+{
+	if (major >= MAX_BLKDEV)
+		return NULL;
+	return blkdevs[major].fops;
+}
+
+struct file_operations * get_chrfops(unsigned int major)
+{
+	if (major >= MAX_CHRDEV)
+		return NULL;
+	return chrdevs[major].fops;
+}
+
+int register_chrdev(unsigned int major, const char * name, struct file_operations *fops)
+{
+	if (major == 0) {
+		for (major = MAX_CHRDEV-1; major > 0; major--) {
+			if (chrdevs[major].fops == fops)
+				return major;
+		}
+		for (major = MAX_CHRDEV-1; major > 0; major--) {
+			if (chrdevs[major].fops == NULL) {
+				chrdevs[major].name = name;
+				chrdevs[major].fops = fops;
+				return major;
+			}
+		}
+		return -EBUSY;
+	}
+	if (major >= MAX_CHRDEV)
+		return -EINVAL;
+	if (chrdevs[major].fops && chrdevs[major].fops != fops)
+		return -EBUSY;
+	chrdevs[major].name = name;
+	chrdevs[major].fops = fops;
+	return 0;
+}
+
+int register_blkdev(unsigned int major, const char * name, struct file_operations *fops)
+{
+	if (major == 0) {
+		for (major = MAX_BLKDEV-1; major > 0; major--) {
+			if (blkdevs[major].fops == fops)
+				return major;
+		}
+		for (major = MAX_BLKDEV-1; major > 0; major--) {
+			if (blkdevs[major].fops == NULL) {
+				blkdevs[major].name = name;
+				blkdevs[major].fops = fops;
+				return major;
+			}
+		}
+		return -EBUSY;
+	}
+	if (major >= MAX_BLKDEV)
+		return -EINVAL;
+	if (blkdevs[major].fops && blkdevs[major].fops != fops)
+		return -EBUSY;
+	blkdevs[major].name = name;
+	blkdevs[major].fops = fops;
+	return 0;
+}
+
+int unregister_chrdev(unsigned int major, const char * name)
+{
+	if (major >= MAX_CHRDEV)
+		return -EINVAL;
+	if (!chrdevs[major].fops)
+		return -EINVAL;
+	if (strcmp(chrdevs[major].name, name))
+		return -EINVAL;
+	chrdevs[major].name = NULL;
+	chrdevs[major].fops = NULL;
+	return 0;
+}
+
+int unregister_blkdev(unsigned int major, const char * name)
+{
+	if (major >= MAX_BLKDEV)
+		return -EINVAL;
+	if (!blkdevs[major].fops)
+		return -EINVAL;
+	if (strcmp(blkdevs[major].name, name))
+		return -EINVAL;
+	blkdevs[major].name = NULL;
+	blkdevs[major].fops = NULL;
+	return 0;
+}
+
+/*
+ * This routine checks whether a removable media has been changed,
+ * and invalidates all buffer-cache-entries in that case. This
+ * is a relatively slow routine, so we have to try to minimize using
+ * it. Thus it is called only upon a 'mount' or 'open'. This
+ * is the best way of combining speed and utility, I think.
+ * People changing diskettes in the middle of an operation deserve
+ * to loose :-)
+ */
+int check_disk_change(dev_t dev)
+{
+	int i;
+	struct file_operations * fops;
+
+	i = MAJOR(dev);
+	if (i >= MAX_BLKDEV || (fops = blkdevs[i].fops) == NULL)
+		return 0;
+	if (fops->check_media_change == NULL)
+		return 0;
+	if (!fops->check_media_change(dev))
+		return 0;
+
+	printk("VFS: Disk change detected on device %d/%d\n",
+					MAJOR(dev), MINOR(dev));
+	for (i=0 ; i<NR_SUPER ; i++)
+		if (super_blocks[i].s_dev == dev)
+			put_super(super_blocks[i].s_dev);
+	invalidate_inodes(dev);
+	invalidate_buffers(dev);
+
+	if (fops->revalidate)
+		fops->revalidate(dev);
+	return 1;
+}
+
+/*
+ * Called every time a block special file is opened
+ */
+int blkdev_open(struct inode * inode, struct file * filp)
+{
+	int i;
+
+	i = MAJOR(inode->i_rdev);
+	if (i >= MAX_BLKDEV || !blkdevs[i].fops)
+		return -ENODEV;
+	filp->f_op = blkdevs[i].fops;
+	if (filp->f_op->open)
+		return filp->f_op->open(inode,filp);
+	return 0;
+}	
+
+/*
+ * Dummy default file-operations: the only thing this does
+ * is contain the open that then fills in the correct operations
+ * depending on the special file...
+ */
+struct file_operations def_blk_fops = {
+	NULL,		/* lseek */
+	NULL,		/* read */
+	NULL,		/* write */
+	NULL,		/* readdir */
+	NULL,		/* select */
+	NULL,		/* ioctl */
+	NULL,		/* mmap */
+	blkdev_open,	/* open */
+	NULL,		/* release */
+};
+
+struct inode_operations blkdev_inode_operations = {
+	&def_blk_fops,		/* default file operations */
+	NULL,			/* create */
+	NULL,			/* lookup */
+	NULL,			/* link */
+	NULL,			/* unlink */
+	NULL,			/* symlink */
+	NULL,			/* mkdir */
+	NULL,			/* rmdir */
+	NULL,			/* mknod */
+	NULL,			/* rename */
+	NULL,			/* readlink */
+	NULL,			/* follow_link */
+	NULL,			/* bmap */
+	NULL,			/* truncate */
+	NULL			/* permission */
+};
+
+/*
+ * Called every time a character special file is opened
+ */
+int chrdev_open(struct inode * inode, struct file * filp)
+{
+	int i;
+
+	i = MAJOR(inode->i_rdev);
+	if (i >= MAX_CHRDEV || !chrdevs[i].fops)
+		return -ENODEV;
+	filp->f_op = chrdevs[i].fops;
+	if (filp->f_op->open)
+		return filp->f_op->open(inode,filp);
+	return 0;
+}
+
+/*
+ * Dummy default file-operations: the only thing this does
+ * is contain the open that then fills in the correct operations
+ * depending on the special file...
+ */
+struct file_operations def_chr_fops = {
+	NULL,		/* lseek */
+	NULL,		/* read */
+	NULL,		/* write */
+	NULL,		/* readdir */
+	NULL,		/* select */
+	NULL,		/* ioctl */
+	NULL,		/* mmap */
+	chrdev_open,	/* open */
+	NULL,		/* release */
+};
+
+struct inode_operations chrdev_inode_operations = {
+	&def_chr_fops,		/* default file operations */
+	NULL,			/* create */
+	NULL,			/* lookup */
+	NULL,			/* link */
+	NULL,			/* unlink */
+	NULL,			/* symlink */
+	NULL,			/* mkdir */
+	NULL,			/* rmdir */
+	NULL,			/* mknod */
+	NULL,			/* rename */
+	NULL,			/* readlink */
+	NULL,			/* follow_link */
+	NULL,			/* bmap */
+	NULL,			/* truncate */
+	NULL			/* permission */
+};