arch/xtensa/platforms/iss/simdisk.c - linux - Git at Google

 /*
  * arch/xtensa/platforms/iss/simdisk.c
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
  * Copyright (C) 2001-2013 Tensilica Inc.
  *   Authors	Victor Prupis
  */

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/string.h>
 #include <linux/blkdev.h>
 #include <linux/bio.h>
 #include <linux/proc_fs.h>
 #include <linux/uaccess.h>
 #include <platform/simcall.h>

 #define SIMDISK_MAJOR 240
 #define SIMDISK_MINORS 1
 #define MAX_SIMDISK_COUNT 10

 struct simdisk {
 	const char *filename;
 	spinlock_t lock;
 	struct gendisk *gd;
 	struct proc_dir_entry *procfile;
 	int users;
 	unsigned long size;
 	int fd;
 };


 static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT;
 module_param(simdisk_count, int, S_IRUGO);
 MODULE_PARM_DESC(simdisk_count, "Number of simdisk units.");

 static int n_files;
 static const char *filename[MAX_SIMDISK_COUNT] = {
 #ifdef CONFIG_SIMDISK0_FILENAME
 	CONFIG_SIMDISK0_FILENAME,
 #ifdef CONFIG_SIMDISK1_FILENAME
 	CONFIG_SIMDISK1_FILENAME,
 #endif
 #endif
 };

 static int simdisk_param_set_filename(const char *val,
 		const struct kernel_param *kp)
 {
 	if (n_files < ARRAY_SIZE(filename))
 		filename[n_files++] = val;
 	else
 		return -EINVAL;
 	return 0;
 }

 static const struct kernel_param_ops simdisk_param_ops_filename = {
 	.set = simdisk_param_set_filename,
 };
 module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0);
 MODULE_PARM_DESC(filename, "Backing storage filename.");

 static int simdisk_major = SIMDISK_MAJOR;

 static void simdisk_transfer(struct simdisk *dev, unsigned long sector,
 		unsigned long nsect, char *buffer, int write)
 {
 	unsigned long offset = sector << SECTOR_SHIFT;
 	unsigned long nbytes = nsect << SECTOR_SHIFT;

 	if (offset > dev->size || dev->size - offset < nbytes) {
 		pr_notice("Beyond-end %s (%ld %ld)\n",
 				write ? "write" : "read", offset, nbytes);
 		return;
 	}

 	spin_lock(&dev->lock);
 	while (nbytes > 0) {
 		unsigned long io;

 		simc_lseek(dev->fd, offset, SEEK_SET);
 		READ_ONCE(*buffer);
 		if (write)
 			io = simc_write(dev->fd, buffer, nbytes);
 		else
 			io = simc_read(dev->fd, buffer, nbytes);
 		if (io == -1) {
 			pr_err("SIMDISK: IO error %d\n", errno);
 			break;
 		}
 		buffer += io;
 		offset += io;
 		nbytes -= io;
 	}
 	spin_unlock(&dev->lock);
 }

 static void simdisk_submit_bio(struct bio *bio)
 {
 	struct simdisk *dev = bio->bi_bdev->bd_disk->private_data;
 	struct bio_vec bvec;
 	struct bvec_iter iter;
 	sector_t sector = bio->bi_iter.bi_sector;

 	bio_for_each_segment(bvec, bio, iter) {
 		char *buffer = bvec_kmap_local(&bvec);
 		unsigned len = bvec.bv_len >> SECTOR_SHIFT;

 		simdisk_transfer(dev, sector, len, buffer,
 				bio_data_dir(bio) == WRITE);
 		sector += len;
 		kunmap_local(buffer);
 	}

 	bio_endio(bio);
 }

 static int simdisk_open(struct gendisk *disk, blk_mode_t mode)
 {
 	struct simdisk *dev = disk->private_data;

 	spin_lock(&dev->lock);
 	++dev->users;
 	spin_unlock(&dev->lock);
 	return 0;
 }

 static void simdisk_release(struct gendisk *disk)
 {
 	struct simdisk *dev = disk->private_data;
 	spin_lock(&dev->lock);
 	--dev->users;
 	spin_unlock(&dev->lock);
 }

 static const struct block_device_operations simdisk_ops = {
 	.owner		= THIS_MODULE,
 	.submit_bio	= simdisk_submit_bio,
 	.open		= simdisk_open,
 	.release	= simdisk_release,
 };

 static struct simdisk *sddev;
 static struct proc_dir_entry *simdisk_procdir;

 static int simdisk_attach(struct simdisk *dev, const char *filename)
 {
 	int err = 0;

 	filename = kstrdup(filename, GFP_KERNEL);
 	if (filename == NULL)
 		return -ENOMEM;

 	spin_lock(&dev->lock);

 	if (dev->fd != -1) {
 		err = -EBUSY;
 		goto out;
 	}
 	dev->fd = simc_open(filename, O_RDWR, 0);
 	if (dev->fd == -1) {
 		pr_err("SIMDISK: Can't open %s: %d\n", filename, errno);
 		err = -ENODEV;
 		goto out;
 	}
 	dev->size = simc_lseek(dev->fd, 0, SEEK_END);
 	set_capacity(dev->gd, dev->size >> SECTOR_SHIFT);
 	dev->filename = filename;
 	pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename);
 out:
 	if (err)
 		kfree(filename);
 	spin_unlock(&dev->lock);

 	return err;
 }

 static int simdisk_detach(struct simdisk *dev)
 {
 	int err = 0;

 	spin_lock(&dev->lock);

 	if (dev->users != 0) {
 		err = -EBUSY;
 	} else if (dev->fd != -1) {
 		if (simc_close(dev->fd)) {
 			pr_err("SIMDISK: error closing %s: %d\n",
 					dev->filename, errno);
 			err = -EIO;
 		} else {
 			pr_info("SIMDISK: %s detached from %s\n",
 					dev->gd->disk_name, dev->filename);
 			dev->fd = -1;
 			kfree(dev->filename);
 			dev->filename = NULL;
 		}
 	}
 	spin_unlock(&dev->lock);
 	return err;
 }

 static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
 			size_t size, loff_t *ppos)
 {
 	struct simdisk *dev = pde_data(file_inode(file));
 	const char *s = dev->filename;
 	if (s) {
 		ssize_t len = strlen(s);
 		char *temp = kmalloc(len + 2, GFP_KERNEL);

 		if (!temp)
 			return -ENOMEM;

 		len = scnprintf(temp, len + 2, "%s\n", s);
 		len = simple_read_from_buffer(buf, size, ppos,
 					      temp, len);

 		kfree(temp);
 		return len;
 	}
 	return simple_read_from_buffer(buf, size, ppos, "\n", 1);
 }

 static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
 			size_t count, loff_t *ppos)
 {
 	char *tmp = memdup_user_nul(buf, count);
 	struct simdisk *dev = pde_data(file_inode(file));
 	int err;

 	if (IS_ERR(tmp))
 		return PTR_ERR(tmp);

 	err = simdisk_detach(dev);
 	if (err != 0)
 		goto out_free;

 	if (count > 0 && tmp[count - 1] == '\n')
 		tmp[count - 1] = 0;

 	if (tmp[0])
 		err = simdisk_attach(dev, tmp);

 	if (err == 0)
 		err = count;
 out_free:
 	kfree(tmp);
 	return err;
 }

 static const struct proc_ops simdisk_proc_ops = {
 	.proc_read	= proc_read_simdisk,
 	.proc_write	= proc_write_simdisk,
 	.proc_lseek	= default_llseek,
 };

 static int __init simdisk_setup(struct simdisk *dev, int which,
 		struct proc_dir_entry *procdir)
 {
 	char tmp[2] = { '0' + which, 0 };
 	int err = -ENOMEM;

 	dev->fd = -1;
 	dev->filename = NULL;
 	spin_lock_init(&dev->lock);
 	dev->users = 0;

 	dev->gd = blk_alloc_disk(NUMA_NO_NODE);
 	if (!dev->gd)
 		goto out;
 	dev->gd->major = simdisk_major;
 	dev->gd->first_minor = which;
 	dev->gd->minors = SIMDISK_MINORS;
 	dev->gd->fops = &simdisk_ops;
 	dev->gd->private_data = dev;
 	snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
 	set_capacity(dev->gd, 0);
 	err = add_disk(dev->gd);
 	if (err)
 		goto out_cleanup_disk;

 	dev->procfile = proc_create_data(tmp, 0644, procdir, &simdisk_proc_ops, dev);

 	return 0;

 out_cleanup_disk:
 	put_disk(dev->gd);
 out:
 	return err;
 }

 static int __init simdisk_init(void)
 {
 	int i;

 	if (register_blkdev(simdisk_major, "simdisk") < 0) {
 		pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
 		return -EIO;
 	}
 	pr_info("SIMDISK: major: %d\n", simdisk_major);

 	if (n_files > simdisk_count)
 		simdisk_count = n_files;
 	if (simdisk_count > MAX_SIMDISK_COUNT)
 		simdisk_count = MAX_SIMDISK_COUNT;

 	sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL);
 	if (sddev == NULL)
 		goto out_unregister;

 	simdisk_procdir = proc_mkdir("simdisk", 0);
 	if (simdisk_procdir == NULL)
 		goto out_free_unregister;

 	for (i = 0; i < simdisk_count; ++i) {
 		if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
 			if (filename[i] != NULL && filename[i][0] != 0 &&
 					(n_files == 0 || i < n_files))
 				simdisk_attach(sddev + i, filename[i]);
 		}
 	}

 	return 0;

 out_free_unregister:
 	kfree(sddev);
 out_unregister:
 	unregister_blkdev(simdisk_major, "simdisk");
 	return -ENOMEM;
 }
 module_init(simdisk_init);

 static void simdisk_teardown(struct simdisk *dev, int which,
 		struct proc_dir_entry *procdir)
 {
 	char tmp[2] = { '0' + which, 0 };

 	simdisk_detach(dev);
 	if (dev->gd) {
 		del_gendisk(dev->gd);
 		put_disk(dev->gd);
 	}
 	remove_proc_entry(tmp, procdir);
 }

 static void __exit simdisk_exit(void)
 {
 	int i;

 	for (i = 0; i < simdisk_count; ++i)
 		simdisk_teardown(sddev + i, i, simdisk_procdir);
 	remove_proc_entry("simdisk", 0);
 	kfree(sddev);
 	unregister_blkdev(simdisk_major, "simdisk");
 }
 module_exit(simdisk_exit);

 MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);

 MODULE_LICENSE("GPL");
	/*
	* arch/xtensa/platforms/iss/simdisk.c
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*
	* Copyright (C) 2001-2013 Tensilica Inc.
	* Authors Victor Prupis
	*/

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/string.h>
	#include <linux/blkdev.h>
	#include <linux/bio.h>
	#include <linux/proc_fs.h>
	#include <linux/uaccess.h>
	#include <platform/simcall.h>

	#define SIMDISK_MAJOR 240
	#define SIMDISK_MINORS 1
	#define MAX_SIMDISK_COUNT 10

	struct simdisk {
	const char *filename;
	spinlock_t lock;
	struct gendisk *gd;
	struct proc_dir_entry *procfile;
	int users;
	unsigned long size;
	int fd;
	};


	static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT;
	module_param(simdisk_count, int, S_IRUGO);
	MODULE_PARM_DESC(simdisk_count, "Number of simdisk units.");

	static int n_files;
	static const char *filename[MAX_SIMDISK_COUNT] = {
	#ifdef CONFIG_SIMDISK0_FILENAME
	CONFIG_SIMDISK0_FILENAME,
	#ifdef CONFIG_SIMDISK1_FILENAME
	CONFIG_SIMDISK1_FILENAME,
	#endif
	#endif
	};

	static int simdisk_param_set_filename(const char *val,
	const struct kernel_param *kp)
	{
	if (n_files < ARRAY_SIZE(filename))
	filename[n_files++] = val;
	else
	return -EINVAL;
	return 0;
	}

	static const struct kernel_param_ops simdisk_param_ops_filename = {
	.set = simdisk_param_set_filename,
	};
	module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0);
	MODULE_PARM_DESC(filename, "Backing storage filename.");

	static int simdisk_major = SIMDISK_MAJOR;

	static void simdisk_transfer(struct simdisk *dev, unsigned long sector,
	unsigned long nsect, char *buffer, int write)
	{
	unsigned long offset = sector << SECTOR_SHIFT;
	unsigned long nbytes = nsect << SECTOR_SHIFT;

	if (offset > dev->size \|\| dev->size - offset < nbytes) {
	pr_notice("Beyond-end %s (%ld %ld)\n",
	write ? "write" : "read", offset, nbytes);
	return;
	}

	spin_lock(&dev->lock);
	while (nbytes > 0) {
	unsigned long io;

	simc_lseek(dev->fd, offset, SEEK_SET);
	READ_ONCE(*buffer);
	if (write)
	io = simc_write(dev->fd, buffer, nbytes);
	else
	io = simc_read(dev->fd, buffer, nbytes);
	if (io == -1) {
	pr_err("SIMDISK: IO error %d\n", errno);
	break;
	}
	buffer += io;
	offset += io;
	nbytes -= io;
	}
	spin_unlock(&dev->lock);
	}

	static void simdisk_submit_bio(struct bio *bio)
	{
	struct simdisk *dev = bio->bi_bdev->bd_disk->private_data;
	struct bio_vec bvec;
	struct bvec_iter iter;
	sector_t sector = bio->bi_iter.bi_sector;

	bio_for_each_segment(bvec, bio, iter) {
	char *buffer = bvec_kmap_local(&bvec);
	unsigned len = bvec.bv_len >> SECTOR_SHIFT;

	simdisk_transfer(dev, sector, len, buffer,
	bio_data_dir(bio) == WRITE);
	sector += len;
	kunmap_local(buffer);
	}

	bio_endio(bio);
	}

	static int simdisk_open(struct gendisk *disk, blk_mode_t mode)
	{
	struct simdisk *dev = disk->private_data;

	spin_lock(&dev->lock);
	++dev->users;
	spin_unlock(&dev->lock);
	return 0;
	}

	static void simdisk_release(struct gendisk *disk)
	{
	struct simdisk *dev = disk->private_data;
	spin_lock(&dev->lock);
	--dev->users;
	spin_unlock(&dev->lock);
	}

	static const struct block_device_operations simdisk_ops = {
	.owner = THIS_MODULE,
	.submit_bio = simdisk_submit_bio,
	.open = simdisk_open,
	.release = simdisk_release,
	};

	static struct simdisk *sddev;
	static struct proc_dir_entry *simdisk_procdir;

	static int simdisk_attach(struct simdisk dev, const char filename)
	{
	int err = 0;

	filename = kstrdup(filename, GFP_KERNEL);
	if (filename == NULL)
	return -ENOMEM;

	spin_lock(&dev->lock);

	if (dev->fd != -1) {
	err = -EBUSY;
	goto out;
	}
	dev->fd = simc_open(filename, O_RDWR, 0);
	if (dev->fd == -1) {
	pr_err("SIMDISK: Can't open %s: %d\n", filename, errno);
	err = -ENODEV;
	goto out;
	}
	dev->size = simc_lseek(dev->fd, 0, SEEK_END);
	set_capacity(dev->gd, dev->size >> SECTOR_SHIFT);
	dev->filename = filename;
	pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename);
	out:
	if (err)
	kfree(filename);
	spin_unlock(&dev->lock);

	return err;
	}

	static int simdisk_detach(struct simdisk *dev)
	{
	int err = 0;

	spin_lock(&dev->lock);

	if (dev->users != 0) {
	err = -EBUSY;
	} else if (dev->fd != -1) {
	if (simc_close(dev->fd)) {
	pr_err("SIMDISK: error closing %s: %d\n",
	dev->filename, errno);
	err = -EIO;
	} else {
	pr_info("SIMDISK: %s detached from %s\n",
	dev->gd->disk_name, dev->filename);
	dev->fd = -1;
	kfree(dev->filename);
	dev->filename = NULL;
	}
	}
	spin_unlock(&dev->lock);
	return err;
	}

	static ssize_t proc_read_simdisk(struct file file, char __user buf,
	size_t size, loff_t *ppos)
	{
	struct simdisk *dev = pde_data(file_inode(file));
	const char *s = dev->filename;
	if (s) {
	ssize_t len = strlen(s);
	char *temp = kmalloc(len + 2, GFP_KERNEL);

	if (!temp)
	return -ENOMEM;

	len = scnprintf(temp, len + 2, "%s\n", s);
	len = simple_read_from_buffer(buf, size, ppos,
	temp, len);

	kfree(temp);
	return len;
	}
	return simple_read_from_buffer(buf, size, ppos, "\n", 1);
	}

	static ssize_t proc_write_simdisk(struct file file, const char __user buf,
	size_t count, loff_t *ppos)
	{
	char *tmp = memdup_user_nul(buf, count);
	struct simdisk *dev = pde_data(file_inode(file));
	int err;

	if (IS_ERR(tmp))
	return PTR_ERR(tmp);

	err = simdisk_detach(dev);
	if (err != 0)
	goto out_free;

	if (count > 0 && tmp[count - 1] == '\n')
	tmp[count - 1] = 0;

	if (tmp[0])
	err = simdisk_attach(dev, tmp);

	if (err == 0)
	err = count;
	out_free:
	kfree(tmp);
	return err;
	}

	static const struct proc_ops simdisk_proc_ops = {
	.proc_read = proc_read_simdisk,
	.proc_write = proc_write_simdisk,
	.proc_lseek = default_llseek,
	};

	static int __init simdisk_setup(struct simdisk *dev, int which,
	struct proc_dir_entry *procdir)
	{
	char tmp[2] = { '0' + which, 0 };
	int err = -ENOMEM;

	dev->fd = -1;
	dev->filename = NULL;
	spin_lock_init(&dev->lock);
	dev->users = 0;

	dev->gd = blk_alloc_disk(NUMA_NO_NODE);
	if (!dev->gd)
	goto out;
	dev->gd->major = simdisk_major;
	dev->gd->first_minor = which;
	dev->gd->minors = SIMDISK_MINORS;
	dev->gd->fops = &simdisk_ops;
	dev->gd->private_data = dev;
	snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
	set_capacity(dev->gd, 0);
	err = add_disk(dev->gd);
	if (err)
	goto out_cleanup_disk;

	dev->procfile = proc_create_data(tmp, 0644, procdir, &simdisk_proc_ops, dev);

	return 0;

	out_cleanup_disk:
	put_disk(dev->gd);
	out:
	return err;
	}

	static int __init simdisk_init(void)
	{
	int i;

	if (register_blkdev(simdisk_major, "simdisk") < 0) {
	pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
	return -EIO;
	}
	pr_info("SIMDISK: major: %d\n", simdisk_major);

	if (n_files > simdisk_count)
	simdisk_count = n_files;
	if (simdisk_count > MAX_SIMDISK_COUNT)
	simdisk_count = MAX_SIMDISK_COUNT;

	sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL);
	if (sddev == NULL)
	goto out_unregister;

	simdisk_procdir = proc_mkdir("simdisk", 0);
	if (simdisk_procdir == NULL)
	goto out_free_unregister;

	for (i = 0; i < simdisk_count; ++i) {
	if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
	if (filename[i] != NULL && filename[i][0] != 0 &&
	(n_files == 0 \|\| i < n_files))
	simdisk_attach(sddev + i, filename[i]);
	}
	}

	return 0;

	out_free_unregister:
	kfree(sddev);
	out_unregister:
	unregister_blkdev(simdisk_major, "simdisk");
	return -ENOMEM;
	}
	module_init(simdisk_init);

	static void simdisk_teardown(struct simdisk *dev, int which,
	struct proc_dir_entry *procdir)
	{
	char tmp[2] = { '0' + which, 0 };

	simdisk_detach(dev);
	if (dev->gd) {
	del_gendisk(dev->gd);
	put_disk(dev->gd);
	}
	remove_proc_entry(tmp, procdir);
	}

	static void __exit simdisk_exit(void)
	{
	int i;

	for (i = 0; i < simdisk_count; ++i)
	simdisk_teardown(sddev + i, i, simdisk_procdir);
	remove_proc_entry("simdisk", 0);
	kfree(sddev);
	unregister_blkdev(simdisk_major, "simdisk");
	}
	module_exit(simdisk_exit);

	MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);

	MODULE_LICENSE("GPL");