bsg: support for full generic block layer SG v3 (3d6392cf) · Commits · EulixOS / Software / Kernel

block/Kconfig

+7 −0

Original line number	Diff line number	Diff line
		@@ -51,4 +51,11 @@ config LSF

		endif # BLOCK

		config BLK_DEV_BSG
		bool "Block layer SG support"
		default y
		---help---
		Saying Y here will enable generic SG (SCSI generic) v3
		support for any block device.

		source block/Kconfig.iosched

block/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@

		obj-$(CONFIG_BLOCK) := elevator.o ll_rw_blk.o ioctl.o genhd.o scsi_ioctl.o

		obj-$(CONFIG_BLK_DEV_BSG) += bsg.o
		obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o
		obj-$(CONFIG_IOSCHED_AS) += as-iosched.o
		obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o

block/bsg.c

0 → 100644

+997 −0

Original line number	Diff line number	Diff line
		/*
		* bsg.c - block layer implementation of the sg v3 interface
		*
		* Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs
		* Copyright (C) 2004 Peter M. Jones <pjones@redhat.com>
		*
		* This file is subject to the terms and conditions of the GNU General Public
		* License version 2. See the file "COPYING" in the main directory of this
		* archive for more details.
		*
		*/
		/*
		* TODO
		* - Should this get merged, block/scsi_ioctl.c will be migrated into
		* this file. To keep maintenance down, it's easier to have them
		* seperated right now.
		*
		*/
		#include <linux/config.h>
		#include <linux/module.h>
		#include <linux/init.h>
		#include <linux/file.h>
		#include <linux/blkdev.h>
		#include <linux/poll.h>
		#include <linux/cdev.h>
		#include <linux/percpu.h>
		#include <linux/uio.h>
		#include <linux/bsg.h>

		#include <scsi/scsi.h>
		#include <scsi/scsi_ioctl.h>
		#include <scsi/scsi_cmnd.h>
		#include <scsi/sg.h>

		static char bsg_version[] = "block layer sg (bsg) 0.4";

		struct bsg_command;

		struct bsg_device {
		struct gendisk *disk;
		request_queue_t *queue;
		spinlock_t lock;
		struct list_head busy_list;
		struct list_head done_list;
		struct hlist_node dev_list;
		atomic_t ref_count;
		int minor;
		int queued_cmds;
		int done_cmds;
		unsigned long *cmd_bitmap;
		struct bsg_command *cmd_map;
		wait_queue_head_t wq_done;
		wait_queue_head_t wq_free;
		char name[BDEVNAME_SIZE];
		int max_queue;
		unsigned long flags;
		};

		enum {
		BSG_F_BLOCK = 1,
		BSG_F_WRITE_PERM = 2,
		};

		/*
		* command allocation bitmap defines
		*/
		#define BSG_CMDS_PAGE_ORDER (1)
		#define BSG_CMDS_PER_LONG (sizeof(unsigned long) * 8)
		#define BSG_CMDS_MASK (BSG_CMDS_PER_LONG - 1)
		#define BSG_CMDS_BYTES (PAGE_SIZE * (1 << BSG_CMDS_PAGE_ORDER))
		#define BSG_CMDS (BSG_CMDS_BYTES / sizeof(struct bsg_command))

		#undef BSG_DEBUG

		#ifdef BSG_DEBUG
		#define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __FUNCTION__, ##args)
		#else
		#define dprintk(fmt, args...)
		#endif

		#define list_entry_bc(entry) list_entry((entry), struct bsg_command, list)

		/*
		* just for testing
		*/
		#define BSG_MAJOR (240)

		static DEFINE_MUTEX(bsg_mutex);
		static int bsg_device_nr;

		#define BSG_LIST_SIZE (8)
		#define bsg_list_idx(minor) ((minor) & (BSG_LIST_SIZE - 1))
		static struct hlist_head bsg_device_list[BSG_LIST_SIZE];

		static struct class *bsg_class;
		static LIST_HEAD(bsg_class_list);

		/*
		* our internal command type
		*/
		struct bsg_command {
		struct bsg_device *bd;
		struct list_head list;
		struct request *rq;
		struct bio *bio;
		int err;
		struct sg_io_hdr hdr;
		struct sg_io_hdr __user *uhdr;
		char sense[SCSI_SENSE_BUFFERSIZE];
		};

		static void bsg_free_command(struct bsg_command *bc)
		{
		struct bsg_device *bd = bc->bd;
		unsigned long bitnr = bc - bd->cmd_map;
		unsigned long flags;

		dprintk("%s: command bit offset %lu\n", bd->name, bitnr);

		spin_lock_irqsave(&bd->lock, flags);
		bd->queued_cmds--;
		__clear_bit(bitnr, bd->cmd_bitmap);
		spin_unlock_irqrestore(&bd->lock, flags);

		wake_up(&bd->wq_free);
		}

		static struct bsg_command __bsg_alloc_command(struct bsg_device bd)
		{
		struct bsg_command *bc = NULL;
		unsigned long *map;
		int free_nr;

		spin_lock_irq(&bd->lock);

		if (bd->queued_cmds >= bd->max_queue)
		goto out;

		for (free_nr = 0, map = bd->cmd_bitmap; *map == ~0UL; map++)
		free_nr += BSG_CMDS_PER_LONG;

		BUG_ON(*map == ~0UL);

		bd->queued_cmds++;
		free_nr += ffz(*map);
		__set_bit(free_nr, bd->cmd_bitmap);
		spin_unlock_irq(&bd->lock);

		bc = bd->cmd_map + free_nr;
		memset(bc, 0, sizeof(*bc));
		bc->bd = bd;
		INIT_LIST_HEAD(&bc->list);
		dprintk("%s: returning free cmd %p (bit %d)\n", bd->name, bc, free_nr);
		return bc;
		out:
		dprintk("%s: failed (depth %d)\n", bd->name, bd->queued_cmds);
		spin_unlock_irq(&bd->lock);
		return bc;
		}

		static inline void
		bsg_del_done_cmd(struct bsg_device bd, struct bsg_command bc)
		{
		bd->done_cmds--;
		list_del(&bc->list);
		}

		static inline void
		bsg_add_done_cmd(struct bsg_device bd, struct bsg_command bc)
		{
		bd->done_cmds++;
		list_add_tail(&bc->list, &bd->done_list);
		wake_up(&bd->wq_done);
		}

		static inline int bsg_io_schedule(struct bsg_device *bd, int state)
		{
		DEFINE_WAIT(wait);
		int ret = 0;

		spin_lock_irq(&bd->lock);

		BUG_ON(bd->done_cmds > bd->queued_cmds);

		/*
		* -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no
		* work to do", even though we return -ENOSPC after this same test
		* during bsg_write() -- there, it means our buffer can't have more
		* bsg_commands added to it, thus has no space left.
		*/
		if (bd->done_cmds == bd->queued_cmds) {
		ret = -ENODATA;
		goto unlock;
		}

		if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
		ret = -EAGAIN;
		goto unlock;
		}

		prepare_to_wait(&bd->wq_done, &wait, state);
		spin_unlock_irq(&bd->lock);
		io_schedule();
		finish_wait(&bd->wq_done, &wait);

		if ((state == TASK_INTERRUPTIBLE) && signal_pending(current))
		ret = -ERESTARTSYS;

		return ret;
		unlock:
		spin_unlock_irq(&bd->lock);
		return ret;
		}

		/*
		* get a new free command, blocking if needed and specified
		*/
		static struct bsg_command bsg_get_command(struct bsg_device bd)
		{
		struct bsg_command *bc;
		int ret;

		do {
		bc = __bsg_alloc_command(bd);
		if (bc)
		break;

		ret = bsg_io_schedule(bd, TASK_INTERRUPTIBLE);
		if (ret) {
		bc = ERR_PTR(ret);
		break;
		}

		} while (1);

		return bc;
		}

		/*
		* Check if sg_io_hdr from user is allowed and valid
		*/
		static int
		bsg_validate_sghdr(request_queue_t q, struct sg_io_hdr hdr, int *rw)
		{
		if (hdr->interface_id != 'S')
		return -EINVAL;
		if (hdr->cmd_len > BLK_MAX_CDB)
		return -EINVAL;
		if (hdr->dxfer_len > (q->max_sectors << 9))
		return -EIO;

		/*
		* looks sane, if no data then it should be fine from our POV
		*/
		if (!hdr->dxfer_len)
		return 0;

		switch (hdr->dxfer_direction) {
		case SG_DXFER_TO_FROM_DEV:
		case SG_DXFER_FROM_DEV:
		*rw = READ;
		break;
		case SG_DXFER_TO_DEV:
		*rw = WRITE;
		break;
		default:
		return -EINVAL;
		}

		return 0;
		}

		/*
		* map sg_io_hdr to a request. for scatter-gather sg_io_hdr, we map
		* each segment to a bio and string multiple bio's to the request
		*/
		static struct request *
		bsg_map_hdr(struct bsg_device bd, int rw, struct sg_io_hdr hdr)
		{
		request_queue_t *q = bd->queue;
		struct sg_iovec iov;
		struct sg_iovec __user *u_iov;
		struct request *rq;
		int ret, i = 0;

		dprintk("map hdr %p/%d/%d\n", hdr->dxferp, hdr->dxfer_len,
		hdr->iovec_count);

		ret = bsg_validate_sghdr(q, hdr, &rw);
		if (ret)
		return ERR_PTR(ret);

		/*
		* map scatter-gather elements seperately and string them to request
		*/
		rq = blk_get_request(q, rw, GFP_KERNEL);
		ret = blk_fill_sghdr_rq(q, rq, hdr, test_bit(BSG_F_WRITE_PERM,
		&bd->flags));
		if (ret) {
		blk_put_request(rq);
		return ERR_PTR(ret);
		}

		if (!hdr->iovec_count) {
		ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len);
		if (ret)
		goto out;
		}

		u_iov = hdr->dxferp;
		for (ret = 0, i = 0; i < hdr->iovec_count; i++, u_iov++) {
		if (copy_from_user(&iov, u_iov, sizeof(iov))) {
		ret = -EFAULT;
		break;
		}

		if (!iov.iov_len \|\| !iov.iov_base) {
		ret = -EINVAL;
		break;
		}

		ret = blk_rq_map_user(q, rq, iov.iov_base, iov.iov_len);
		if (ret)
		break;
		}

		/*
		* bugger, cleanup
		*/
		if (ret) {
		out:
		dprintk("failed map at %d: %d\n", i, ret);
		blk_unmap_sghdr_rq(rq, hdr);
		rq = ERR_PTR(ret);
		}

		return rq;
		}

		/*
		* async completion call-back from the block layer, when scsi/ide/whatever
		* calls end_that_request_last() on a request
		*/
		static void bsg_rq_end_io(struct request *rq, int uptodate)
		{
		struct bsg_command *bc = rq->end_io_data;
		struct bsg_device *bd = bc->bd;
		unsigned long flags;

		dprintk("%s: finished rq %p bio %p, bc %p offset %ld stat %d\n",
		bd->name, rq, bc, bc->bio, bc - bd->cmd_map, uptodate);

		bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);

		spin_lock_irqsave(&bd->lock, flags);
		list_del(&bc->list);
		bsg_add_done_cmd(bd, bc);
		spin_unlock_irqrestore(&bd->lock, flags);
		}

		/*
		* do final setup of a 'bc' and submit the matching 'rq' to the block
		* layer for io
		*/
		static void bsg_add_command(struct bsg_device bd, request_queue_t q,
		struct bsg_command bc, struct request rq)
		{
		rq->sense = bc->sense;
		rq->sense_len = 0;

		/*
		* add bc command to busy queue and submit rq for io
		*/
		bc->rq = rq;
		bc->bio = rq->bio;
		bc->hdr.duration = jiffies;
		spin_lock_irq(&bd->lock);
		list_add_tail(&bc->list, &bd->busy_list);
		spin_unlock_irq(&bd->lock);

		dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc);

		rq->end_io_data = bc;
		blk_execute_rq_nowait(q, bd->disk, rq, 1, bsg_rq_end_io);
		}

		static inline struct bsg_command bsg_next_done_cmd(struct bsg_device bd)
		{
		struct bsg_command *bc = NULL;

		spin_lock_irq(&bd->lock);
		if (bd->done_cmds) {
		bc = list_entry_bc(bd->done_list.next);
		bsg_del_done_cmd(bd, bc);
		}
		spin_unlock_irq(&bd->lock);

		return bc;
		}

		/*
		* Get a finished command from the done list
		*/
		static struct bsg_command __bsg_get_done_cmd(struct bsg_device bd, int state)
		{
		struct bsg_command *bc;
		int ret;

		do {
		bc = bsg_next_done_cmd(bd);
		if (bc)
		break;

		ret = bsg_io_schedule(bd, state);
		if (ret) {
		bc = ERR_PTR(ret);
		break;
		}
		} while (1);

		dprintk("%s: returning done %p\n", bd->name, bc);

		return bc;
		}

		static struct bsg_command *
		bsg_get_done_cmd(struct bsg_device bd, const struct iovec iov)
		{
		return __bsg_get_done_cmd(bd, TASK_INTERRUPTIBLE);
		}

		static struct bsg_command *
		bsg_get_done_cmd_nosignals(struct bsg_device *bd)
		{
		return __bsg_get_done_cmd(bd, TASK_UNINTERRUPTIBLE);
		}

		static int bsg_complete_all_commands(struct bsg_device *bd)
		{
		struct bsg_command *bc;
		int ret, tret;

		dprintk("%s: entered\n", bd->name);

		set_bit(BSG_F_BLOCK, &bd->flags);

		/*
		* wait for all commands to complete
		*/
		ret = 0;
		do {
		ret = bsg_io_schedule(bd, TASK_UNINTERRUPTIBLE);
		/*
		* look for -ENODATA specifically -- we'll sometimes get
		* -ERESTARTSYS when we've taken a signal, but we can't
		* return until we're done freeing the queue, so ignore
		* it. The signal will get handled when we're done freeing
		* the bsg_device.
		*/
		} while (ret != -ENODATA);

		/*
		* discard done commands
		*/
		ret = 0;
		do {
		bc = bsg_get_done_cmd_nosignals(bd);

		/*
		* we _must_ complete before restarting, because
		* bsg_release can't handle this failing.
		*/
		if (PTR_ERR(bc) == -ERESTARTSYS)
		continue;
		if (IS_ERR(bc)) {
		ret = PTR_ERR(bc);
		break;
		}

		tret = blk_complete_sghdr_rq(bc->rq, &bc->hdr, bc->bio);
		if (!ret)
		ret = tret;

		bsg_free_command(bc);
		} while (1);

		return ret;
		}

		typedef struct bsg_command (bsg_command_callback)(struct bsg_device bd, const struct iovec iov);

		static ssize_t
		__bsg_read(char __user *buf, size_t count, bsg_command_callback get_bc,
		struct bsg_device bd, const struct iovec iov, ssize_t *bytes_read)
		{
		struct bsg_command *bc;
		int nr_commands, ret;

		if (count % sizeof(struct sg_io_hdr))
		return -EINVAL;

		ret = 0;
		nr_commands = count / sizeof(struct sg_io_hdr);
		while (nr_commands) {
		bc = get_bc(bd, iov);
		if (IS_ERR(bc)) {
		ret = PTR_ERR(bc);
		break;
		}

		/*
		* this is the only case where we need to copy data back
		* after completing the request. so do that here,
		* bsg_complete_work() cannot do that for us
		*/
		ret = blk_complete_sghdr_rq(bc->rq, &bc->hdr, bc->bio);

		if (copy_to_user(buf, (char *) &bc->hdr, sizeof(bc->hdr)))
		ret = -EFAULT;

		bsg_free_command(bc);

		if (ret)
		break;

		buf += sizeof(struct sg_io_hdr);
		*bytes_read += sizeof(struct sg_io_hdr);
		nr_commands--;
		}

		return ret;
		}

		static inline void bsg_set_block(struct bsg_device bd, struct file file)
		{
		if (file->f_flags & O_NONBLOCK)
		clear_bit(BSG_F_BLOCK, &bd->flags);
		else
		set_bit(BSG_F_BLOCK, &bd->flags);
		}

		static inline void bsg_set_write_perm(struct bsg_device bd, struct file file)
		{
		if (file->f_mode & FMODE_WRITE)
		set_bit(BSG_F_WRITE_PERM, &bd->flags);
		else
		clear_bit(BSG_F_WRITE_PERM, &bd->flags);
		}

		static inline int err_block_err(int ret)
		{
		if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
		return 1;

		return 0;
		}

		static ssize_t
		bsg_read(struct file file, char __user buf, size_t count, loff_t *ppos)
		{
		struct bsg_device *bd = file->private_data;
		int ret;
		ssize_t bytes_read;

		dprintk("%s: read %lu bytes\n", bd->name, count);

		bsg_set_block(bd, file);
		bytes_read = 0;
		ret = __bsg_read(buf, count, bsg_get_done_cmd,
		bd, NULL, &bytes_read);
		*ppos = bytes_read;

		if (!bytes_read \|\| (bytes_read && err_block_err(ret)))
		bytes_read = ret;

		return bytes_read;
		}

		static ssize_t __bsg_write(struct bsg_device bd, const char __user buf,
		size_t count, ssize_t *bytes_read)
		{
		struct bsg_command *bc;
		struct request *rq;
		int ret, nr_commands;

		if (count % sizeof(struct sg_io_hdr))
		return -EINVAL;

		nr_commands = count / sizeof(struct sg_io_hdr);
		rq = NULL;
		bc = NULL;
		ret = 0;
		while (nr_commands) {
		request_queue_t *q = bd->queue;
		int rw = READ;

		bc = bsg_get_command(bd);
		if (!bc)
		break;
		if (IS_ERR(bc)) {
		ret = PTR_ERR(bc);
		bc = NULL;
		break;
		}

		bc->uhdr = (struct sg_io_hdr __user *) buf;
		if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
		ret = -EFAULT;
		break;
		}

		/*
		* get a request, fill in the blanks, and add to request queue
		*/
		rq = bsg_map_hdr(bd, rw, &bc->hdr);
		if (IS_ERR(rq)) {
		ret = PTR_ERR(rq);
		rq = NULL;
		break;
		}

		bsg_add_command(bd, q, bc, rq);
		bc = NULL;
		rq = NULL;
		nr_commands--;
		buf += sizeof(struct sg_io_hdr);
		*bytes_read += sizeof(struct sg_io_hdr);
		}

		if (rq)
		blk_unmap_sghdr_rq(rq, &bc->hdr);
		if (bc)
		bsg_free_command(bc);

		return ret;
		}

		static ssize_t
		bsg_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
		{
		struct bsg_device *bd = file->private_data;
		ssize_t bytes_read;
		int ret;

		dprintk("%s: write %lu bytes\n", bd->name, count);

		bsg_set_block(bd, file);
		bsg_set_write_perm(bd, file);

		bytes_read = 0;
		ret = __bsg_write(bd, buf, count, &bytes_read);
		*ppos = bytes_read;

		/*
		* return bytes written on non-fatal errors
		*/
		if (!bytes_read \|\| (bytes_read && err_block_err(ret)))
		bytes_read = ret;

		dprintk("%s: returning %lu\n", bd->name, bytes_read);
		return bytes_read;
		}

		static void bsg_free_device(struct bsg_device *bd)
		{
		if (bd->cmd_map)
		free_pages((unsigned long) bd->cmd_map, BSG_CMDS_PAGE_ORDER);

		kfree(bd->cmd_bitmap);
		kfree(bd);
		}

		static struct bsg_device *bsg_alloc_device(void)
		{
		struct bsg_command *cmd_map;
		unsigned long *cmd_bitmap;
		struct bsg_device *bd;
		int bits;

		bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
		if (unlikely(!bd))
		return NULL;

		spin_lock_init(&bd->lock);

		bd->max_queue = BSG_CMDS;

		bits = (BSG_CMDS / BSG_CMDS_PER_LONG) + 1;
		cmd_bitmap = kzalloc(bits * sizeof(unsigned long), GFP_KERNEL);
		if (!cmd_bitmap)
		goto out_free_bd;
		bd->cmd_bitmap = cmd_bitmap;

		cmd_map = (void *) __get_free_pages(GFP_KERNEL \| __GFP_ZERO,
		BSG_CMDS_PAGE_ORDER);
		if (!cmd_map)
		goto out_free_bitmap;
		bd->cmd_map = cmd_map;

		INIT_LIST_HEAD(&bd->busy_list);
		INIT_LIST_HEAD(&bd->done_list);
		INIT_HLIST_NODE(&bd->dev_list);

		init_waitqueue_head(&bd->wq_free);
		init_waitqueue_head(&bd->wq_done);
		return bd;

		out_free_bitmap:
		kfree(cmd_bitmap);
		out_free_bd:
		kfree(bd);
		return NULL;
		}

		static int bsg_put_device(struct bsg_device *bd)
		{
		int ret = 0;

		mutex_lock(&bsg_mutex);

		if (!atomic_dec_and_test(&bd->ref_count))
		goto out;

		dprintk("%s: tearing down\n", bd->name);

		/*
		* close can always block
		*/
		set_bit(BSG_F_BLOCK, &bd->flags);

		/*
		* correct error detection baddies here again. it's the responsibility
		* of the app to properly reap commands before close() if it wants
		* fool-proof error detection
		*/
		ret = bsg_complete_all_commands(bd);

		blk_put_queue(bd->queue);
		hlist_del(&bd->dev_list);
		bsg_free_device(bd);
		out:
		mutex_unlock(&bsg_mutex);
		return ret;
		}

		static struct bsg_device bsg_add_device(struct inode inode,
		struct gendisk *disk,
		struct file *file)
		{
		struct bsg_device *bd = NULL;
		#ifdef BSG_DEBUG
		unsigned char buf[32];
		#endif

		bd = bsg_alloc_device();
		if (!bd)
		return ERR_PTR(-ENOMEM);

		bd->disk = disk;
		bd->queue = disk->queue;
		kobject_get(&disk->queue->kobj);
		bsg_set_block(bd, file);

		atomic_set(&bd->ref_count, 1);
		bd->minor = iminor(inode);
		mutex_lock(&bsg_mutex);
		hlist_add_head(&bd->dev_list,&bsg_device_list[bsg_list_idx(bd->minor)]);

		strncpy(bd->name, disk->disk_name, sizeof(bd->name) - 1);
		dprintk("bound to <%s>, max queue %d\n",
		format_dev_t(buf, i->i_rdev), bd->max_queue);

		mutex_unlock(&bsg_mutex);
		return bd;
		}

		static struct bsg_device *__bsg_get_device(int minor)
		{
		struct hlist_head *list = &bsg_device_list[bsg_list_idx(minor)];
		struct bsg_device *bd = NULL;
		struct hlist_node *entry;

		mutex_lock(&bsg_mutex);

		hlist_for_each(entry, list) {
		bd = hlist_entry(entry, struct bsg_device, dev_list);
		if (bd->minor == minor) {
		atomic_inc(&bd->ref_count);
		break;
		}

		bd = NULL;
		}

		mutex_unlock(&bsg_mutex);
		return bd;
		}

		static struct bsg_device bsg_get_device(struct inode inode, struct file *file)
		{
		struct bsg_device *bd = __bsg_get_device(iminor(inode));
		struct bsg_class_device bcd, __bcd;

		if (bd)
		return bd;

		/*
		* find the class device
		*/
		bcd = NULL;
		mutex_lock(&bsg_mutex);
		list_for_each_entry(__bcd, &bsg_class_list, list) {
		if (__bcd->minor == iminor(inode)) {
		bcd = __bcd;
		break;
		}
		}
		mutex_unlock(&bsg_mutex);

		if (!bcd)
		return ERR_PTR(-ENODEV);

		return bsg_add_device(inode, bcd->disk, file);
		}

		static int bsg_open(struct inode inode, struct file file)
		{
		struct bsg_device *bd = bsg_get_device(inode, file);

		if (IS_ERR(bd))
		return PTR_ERR(bd);

		file->private_data = bd;
		return 0;
		}

		static int bsg_release(struct inode inode, struct file file)
		{
		struct bsg_device *bd = file->private_data;

		file->private_data = NULL;
		return bsg_put_device(bd);
		}

		static unsigned int bsg_poll(struct file file, poll_table wait)
		{
		struct bsg_device *bd = file->private_data;
		unsigned int mask = 0;

		poll_wait(file, &bd->wq_done, wait);
		poll_wait(file, &bd->wq_free, wait);

		spin_lock_irq(&bd->lock);
		if (!list_empty(&bd->done_list))
		mask \|= POLLIN \| POLLRDNORM;
		if (bd->queued_cmds >= bd->max_queue)
		mask \|= POLLOUT;
		spin_unlock_irq(&bd->lock);

		return mask;
		}

		static int
		bsg_ioctl(struct inode inode, struct file file, unsigned int cmd,
		unsigned long arg)
		{
		struct bsg_device *bd = file->private_data;
		int __user uarg = (int __user ) arg;

		if (!bd)
		return -ENXIO;

		switch (cmd) {
		/*
		* our own ioctls
		*/
		case SG_GET_COMMAND_Q:
		return put_user(bd->max_queue, uarg);
		case SG_SET_COMMAND_Q: {
		int queue;

		if (get_user(queue, uarg))
		return -EFAULT;
		if (queue > BSG_CMDS \|\| queue < 1)
		return -EINVAL;

		bd->max_queue = queue;
		return 0;
		}

		/*
		* SCSI/sg ioctls
		*/
		case SG_GET_VERSION_NUM:
		case SCSI_IOCTL_GET_IDLUN:
		case SCSI_IOCTL_GET_BUS_NUMBER:
		case SG_SET_TIMEOUT:
		case SG_GET_TIMEOUT:
		case SG_GET_RESERVED_SIZE:
		case SG_SET_RESERVED_SIZE:
		case SG_EMULATED_HOST:
		case SG_IO:
		case SCSI_IOCTL_SEND_COMMAND: {
		void __user uarg = (void __user ) arg;
		return scsi_cmd_ioctl(file, bd->disk, cmd, uarg);
		}
		/*
		* block device ioctls
		*/
		default:
		#if 0
		return ioctl_by_bdev(bd->bdev, cmd, arg);
		#else
		return -ENOTTY;
		#endif
		}
		}

		static struct file_operations bsg_fops = {
		.read = bsg_read,
		.write = bsg_write,
		.poll = bsg_poll,
		.open = bsg_open,
		.release = bsg_release,
		.ioctl = bsg_ioctl,
		.owner = THIS_MODULE,
		};

		void bsg_unregister_disk(struct gendisk *disk)
		{
		struct bsg_class_device *bcd = &disk->bsg_dev;

		if (!bcd->class_dev)
		return;

		mutex_lock(&bsg_mutex);
		sysfs_remove_link(&bcd->disk->queue->kobj, "bsg");
		class_device_destroy(bsg_class, MKDEV(BSG_MAJOR, bcd->minor));
		bcd->class_dev = NULL;
		list_del_init(&bcd->list);
		mutex_unlock(&bsg_mutex);
		}

		int bsg_register_disk(struct gendisk *disk)
		{
		request_queue_t *q = disk->queue;
		struct bsg_class_device *bcd;
		dev_t dev;

		/*
		* we need a proper transport to send commands, not a stacked device
		*/
		if (!q->request_fn)
		return 0;

		bcd = &disk->bsg_dev;
		memset(bcd, 0, sizeof(*bcd));
		INIT_LIST_HEAD(&bcd->list);

		mutex_lock(&bsg_mutex);
		dev = MKDEV(BSG_MAJOR, bsg_device_nr);
		bcd->minor = bsg_device_nr;
		bsg_device_nr++;
		bcd->disk = disk;
		bcd->class_dev = class_device_create(bsg_class, NULL, dev, bcd->dev, "%s", disk->disk_name);
		list_add_tail(&bcd->list, &bsg_class_list);
		sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
		mutex_unlock(&bsg_mutex);
		return 0;
		}

		static int __init bsg_init(void)
		{
		int ret, i;

		for (i = 0; i < BSG_LIST_SIZE; i++)
		INIT_HLIST_HEAD(&bsg_device_list[i]);

		bsg_class = class_create(THIS_MODULE, "bsg");
		if (IS_ERR(bsg_class))
		return PTR_ERR(bsg_class);

		ret = register_chrdev(BSG_MAJOR, "bsg", &bsg_fops);
		if (ret) {
		class_destroy(bsg_class);
		return ret;
		}

		printk(KERN_INFO "%s loaded\n", bsg_version);
		return 0;
		}

		MODULE_AUTHOR("Jens Axboe");
		MODULE_DESCRIPTION("Block layer SGSI generic (sg) driver");
		MODULE_LICENSE("GPL");

		subsys_initcall(bsg_init);

block/ll_rw_blk.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -4091,6 +4091,13 @@ int blk_register_queue(struct gendisk *disk)
		return ret;
		}

		ret = bsg_register_disk(disk);
		if (ret) {
		elv_unregister_queue(q);
		kobject_unregister(&q->kobj);
		return ret;
		}

		return 0;
		}

		@@ -4099,6 +4106,7 @@ void blk_unregister_queue(struct gendisk *disk)
		request_queue_t *q = disk->queue;

		if (q && q->request_fn) {
		bsg_unregister_disk(disk);
		elv_unregister_queue(q);

		kobject_uevent(&q->kobj, KOBJ_REMOVE);

block/scsi_ioctl.c

+102 −61

File changed.

Preview size limit exceeded, changes collapsed.