path: root/arch/um/drivers/ubd_kern.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2018 Cambridge Greys Ltd
 * Copyright (C) 2015-2016 Anton Ivanov (aivanov@brocade.com)
 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
 */

/* 2001-09-28...2002-04-17
 * Partition stuff by James_McMechan@hotmail.com
 * old style ubd by setting UBD_SHIFT to 0
 * 2002-09-27...2002-10-18 massive tinkering for 2.5
 * partitions have changed in 2.5
 * 2003-01-29 more tinkering for 2.5.59-1
 * This should now address the sysfs problems and has
 * the symlink for devfs to allow for booting with
 * the common /dev/ubd/discX/... names rather than
 * only /dev/ubdN/discN this version also has lots of
 * clean ups preparing for ubd-many.
 * James McMechan
 */

#define UBD_SHIFT 4

#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/ata.h>
#include <linux/hdreg.h>
#include <linux/major.h>
#include <linux/cdrom.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/platform_device.h>
#include <linux/scatterlist.h>
#include <asm/tlbflush.h>
#include <kern_util.h>
#include "mconsole_kern.h"
#include <init.h>
#include <irq_kern.h>
#include "ubd.h"
#include <os.h>
#include "cow.h"

/* Max request size is determined by sector mask - 32K */
#define UBD_MAX_REQUEST (8 * sizeof(long))

struct io_desc {
	char *buffer;
	unsigned long length;
	unsigned long sector_mask;
	unsigned long long cow_offset;
	unsigned long bitmap_words[2];
};

struct io_thread_req {
	struct request *req;
	int fds[2];
	unsigned long offsets[2];
	unsigned long long offset;
	int sectorsize;
	int error;

	int desc_cnt;
	/* io_desc has to be the last element of the struct */
	struct io_desc io_desc[];
};


static struct io_thread_req * (*irq_req_buffer)[];
static struct io_thread_req *irq_remainder;
static int irq_remainder_size;

static struct io_thread_req * (*io_req_buffer)[];
static struct io_thread_req *io_remainder;
static int io_remainder_size;



static inline int ubd_test_bit(__u64 bit, unsigned char *data)
{
	__u64 n;
	int bits, off;

	bits = sizeof(data[0]) * 8;
	n = bit / bits;
	off = bit % bits;
	return (data[n] & (1 << off)) != 0;
}

static inline void ubd_set_bit(__u64 bit, unsigned char *data)
{
	__u64 n;
	int bits, off;

	bits = sizeof(data[0]) * 8;
	n = bit / bits;
	off = bit % bits;
	data[n] |= (1 << off);
}
/*End stuff from ubd_user.h*/

#define DRIVER_NAME "uml-blkdev"

static DEFINE_MUTEX(ubd_lock);
static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */

static int ubd_open(struct gendisk *disk, blk_mode_t mode);
static void ubd_release(struct gendisk *disk);
static int ubd_ioctl(struct block_device *bdev, blk_mode_t mode,
		     unsigned int cmd, unsigned long arg);
static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo);

#define MAX_DEV (16)

static const struct block_device_operations ubd_blops = {
        .owner		= THIS_MODULE,
        .open		= ubd_open,
        .release	= ubd_release,
        .ioctl		= ubd_ioctl,
        .compat_ioctl	= blkdev_compat_ptr_ioctl,
	.getgeo		= ubd_getgeo,
};

/* Protected by ubd_lock */
static struct gendisk *ubd_gendisk[MAX_DEV];

#ifdef CONFIG_BLK_DEV_UBD_SYNC
#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
					 .cl = 1 })
#else
#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
					 .cl = 1 })
#endif
static struct openflags global_openflags = OPEN_FLAGS;

struct cow {
	/* backing file name */
	char *file;
	/* backing file fd */
	int fd;
	unsigned long *bitmap;
	unsigned long bitmap_len;
	int bitmap_offset;
	int data_offset;
};

#define MAX_SG 64

struct ubd {
	/* name (and fd, below) of the file opened for writing, either the
	 * backing or the cow file. */
	char *file;
	char *serial;
	int count;
	int fd;
	__u64 size;
	struct openflags boot_openflags;
	struct openflags openflags;
	unsigned shared:1;
	unsigned no_cow:1;
	unsigned no_trim:1;
	struct cow cow;
	struct platform_device pdev;
	struct request_queue *queue;
	struct blk_mq_tag_set tag_set;
	spinlock_t lock;
};

#define DEFAULT_COW { \
	.file =			NULL, \
	.fd =			-1,	\
	.bitmap =		NULL, \
	.bitmap_offset =	0, \
	.data_offset =		0, \
}

#define DEFAULT_UBD { \
	.file = 		NULL, \
	.serial =		NULL, \
	.count =		0, \
	.fd =			-1, \
	.size =			-1, \
	.boot_openflags =	OPEN_FLAGS, \
	.openflags =		OPEN_FLAGS, \
	.no_cow =               0, \
	.no_trim =		0, \
	.shared =		0, \
	.cow =			DEFAULT_COW, \
	.lock =			__SPIN_LOCK_UNLOCKED(ubd_devs.lock), \
}

/* Protected by ubd_lock */
static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD };

static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
				 const struct blk_mq_queue_data *bd);

static int fake_ide_setup(char *str)
{
	pr_warn("The fake_ide option has been removed\n");
	return 1;
}
__setup("fake_ide", fake_ide_setup);

__uml_help(fake_ide_setup,
"fake_ide\n"
"    Obsolete stub.\n\n"
);

static int parse_unit(char **ptr)
{
	char *str = *ptr, *end;
	int n = -1;

	if(isd