--- /dev/null
+/*
+ * bsg.c - block layer implementation of the sg v4 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.
+ *
+ */
+#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/jiffies.h>
+#include <linux/percpu.h>
+#include <linux/uio.h>
+#include <linux/idr.h>
+#include <linux/bsg.h>
+#include <linux/slab.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/sg.h>
+
+#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
+#define BSG_VERSION "0.4"
+
+struct bsg_device {
+ struct request_queue *queue;
+ spinlock_t lock;
+ struct list_head busy_list;
+ struct list_head done_list;
+ struct hlist_node dev_list;
+ atomic_t ref_count;
+ int queued_cmds;
+ int done_cmds;
+ wait_queue_head_t wq_done;
+ wait_queue_head_t wq_free;
+ char name[20];
+ int max_queue;
+ unsigned long flags;
+};
+
+enum {
+ BSG_F_BLOCK = 1,
+};
+
+#define BSG_DEFAULT_CMDS 64
+#define BSG_MAX_DEVS 32768
+
+#undef BSG_DEBUG
+
+#ifdef BSG_DEBUG
+#define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args)
+#else
+#define dprintk(fmt, args...)
+#endif
+
+static DEFINE_MUTEX(bsg_mutex);
+static DEFINE_IDR(bsg_minor_idr);
+
+#define BSG_LIST_ARRAY_SIZE 8
+static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
+
+static struct class *bsg_class;
+static int bsg_major;
+
+static struct kmem_cache *bsg_cmd_cachep;
+
+/*
+ * our internal command type
+ */
+struct bsg_command {
+ struct bsg_device *bd;
+ struct list_head list;
+ struct request *rq;
+ struct bio *bio;
+ struct bio *bidi_bio;
+ int err;
+ struct sg_io_v4 hdr;
+ char sense[SCSI_SENSE_BUFFERSIZE];
+};
+
+static void bsg_free_command(struct bsg_command *bc)
+{
+ struct bsg_device *bd = bc->bd;
+ unsigned long flags;
+
+ kmem_cache_free(bsg_cmd_cachep, bc);
+
+ spin_lock_irqsave(&bd->lock, flags);
+ bd->queued_cmds--;
+ 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 = ERR_PTR(-EINVAL);
+
+ spin_lock_irq(&bd->lock);
+
+ if (bd->queued_cmds >= bd->max_queue)
+ goto out;
+
+ bd->queued_cmds++;
+ spin_unlock_irq(&bd->lock);
+
+ bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL);
+ if (unlikely(!bc)) {
+ spin_lock_irq(&bd->lock);
+ bd->queued_cmds--;
+ bc = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ bc->bd = bd;
+ INIT_LIST_HEAD(&bc->list);
+ dprintk("%s: returning free cmd %p\n", bd->name, bc);
+ return bc;
+out:
+ spin_unlock_irq(&bd->lock);
+ return bc;
+}
+
+static inline struct hlist_head *bsg_dev_idx_hash(int index)
+{
+ return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
+}
+
+static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
+ struct sg_io_v4 *hdr, struct bsg_device *bd,
+ fmode_t has_write_perm)
+{
+ if (hdr->request_len > BLK_MAX_CDB) {
+ rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
+ if (!rq->cmd)
+ return -ENOMEM;
+ }
+
+ if (copy_from_user(rq->cmd, (void __user *)(unsigned long)hdr->request,
+ hdr->request_len))
+ return -EFAULT;
+
+ if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
+ if (blk_verify_command(rq->cmd, has_write_perm))
+ return -EPERM;
+ } else if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ /*
+ * fill in request structure
+ */
+ rq->cmd_len = hdr->request_len;
+
+ rq->timeout = msecs_to_jiffies(hdr->timeout);
+ if (!rq->timeout)
+ rq->timeout = q->sg_timeout;
+ if (!rq->timeout)
+ rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
+ if (rq->timeout < BLK_MIN_SG_TIMEOUT)
+ rq->timeout = BLK_MIN_SG_TIMEOUT;
+
+ return 0;
+}
+
+/*
+ * Check if sg_io_v4 from user is allowed and valid
+ */
+static int
+bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
+{
+ int ret = 0;
+
+ if (hdr->guard != 'Q')
+ return -EINVAL;
+
+ switch (hdr->protocol) {
+ case BSG_PROTOCOL_SCSI:
+ switch (hdr->subprotocol) {
+ case BSG_SUB_PROTOCOL_SCSI_CMD:
+ case BSG_SUB_PROTOCOL_SCSI_TRANSPORT:
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ *rw = hdr->dout_xfer_len ? WRITE : READ;
+ return ret;
+}
+
+/*
+ * map sg_io_v4 to a request.
+ */
+static struct request *
+bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
+ u8 *sense)
+{
+ struct request_queue *q = bd->queue;
+ struct request *rq, *next_rq = NULL;
+ int ret, rw;
+ unsigned int dxfer_len;
+ void __user *dxferp = NULL;
+ struct bsg_class_device *bcd = &q->bsg_dev;
+
+ /* if the LLD has been removed then the bsg_unregister_queue will
+ * eventually be called and the class_dev was freed, so we can no
+ * longer use this request_queue. Return no such address.
+ */
+ if (!bcd->class_dev)
+ return ERR_PTR(-ENXIO);
+
+ dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
+ hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
+ hdr->din_xfer_len);
+
+ ret = bsg_validate_sgv4_hdr(q, hdr, &rw);
+ if (ret)
+ return ERR_PTR(ret);
+
+ /*
+ * map scatter-gather elements separately and string them to request
+ */
+ rq = blk_get_request(q, rw, GFP_KERNEL);
+ if (IS_ERR(rq))
+ return rq;
+ blk_rq_set_block_pc(rq);
+
+ ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
+ if (ret)
+ goto out;
+
+ if (rw == WRITE && hdr->din_xfer_len) {
+ if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ next_rq = blk_get_request(q, READ, GFP_KERNEL);
+ if (IS_ERR(next_rq)) {
+ ret = PTR_ERR(next_rq);
+ next_rq = NULL;
+ goto out;
+ }
+ rq->next_rq = next_rq;
+ next_rq->cmd_type = rq->cmd_type;
+
+ dxferp = (void __user *)(unsigned long)hdr->din_xferp;
+ ret = blk_rq_map_user(q, next_rq, NULL, dxferp,
+ hdr->din_xfer_len, GFP_KERNEL);
+ if (ret)
+ goto out;
+ }
+
+ if (hdr->dout_xfer_len) {
+ dxfer_len = hdr->dout_xfer_len;
+ dxferp = (void __user *)(unsigned long)hdr->dout_xferp;
+ } else if (hdr->din_xfer_len) {
+ dxfer_len = hdr->din_xfer_len;
+ dxferp = (void __user *)(unsigned long)hdr->din_xferp;
+ } else
+ dxfer_len = 0;
+
+ if (dxfer_len) {
+ ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len,
+ GFP_KERNEL);
+ if (ret)
+ goto out;
+ }
+
+ rq->sense = sense;
+ rq->sense_len = 0;
+
+ return rq;
+out:
+ if (rq->cmd != rq->__cmd)
+ kfree(rq->cmd);
+ blk_put_request(rq);
+ if (next_rq) {
+ blk_rq_unmap_user(next_rq->bio);
+ blk_put_request(next_rq);
+ }
+ return ERR_PTR(ret);
+}
+
+/*
+ * 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 bc %p, bio %p stat %d\n",
+ bd->name, rq, bc, bc->bio, uptodate);
+
+ bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
+
+ spin_lock_irqsave(&bd->lock, flags);
+ list_move_tail(&bc->list, &bd->done_list);
+ bd->done_cmds++;
+ spin_unlock_irqrestore(&bd->lock, flags);
+
+ wake_up(&bd->wq_done);
+}
+
+/*
+ * 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, struct request_queue *q,
+ struct bsg_command *bc, struct request *rq)
+{
+ int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL));
+
+ /*
+ * add bc command to busy queue and submit rq for io
+ */
+ bc->rq = rq;
+ bc->bio = rq->bio;
+ if (rq->next_rq)
+ bc->bidi_bio = rq->next_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, NULL, rq, at_head, bsg_rq_end_io);
+}
+
+static 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_first_entry(&bd->done_list, struct bsg_command, list);
+ list_del(&bc->list);
+ bd->done_cmds--;
+ }
+ 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)
+{
+ struct bsg_command *bc;
+ int ret;
+
+ do {
+ bc = bsg_next_done_cmd(bd);
+ if (bc)
+ break;
+
+ if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
+ bc = ERR_PTR(-EAGAIN);
+ break;
+ }
+
+ ret = wait_event_interruptible(bd->wq_done, bd->done_cmds);
+ if (ret) {
+ bc = ERR_PTR(-ERESTARTSYS);
+ break;
+ }
+ } while (1);
+
+ dprintk("%s: returning done %p\n", bd->name, bc);
+
+ return bc;
+}
+
+static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
+ struct bio *bio, struct bio *bidi_bio)
+{
+ int ret = 0;
+
+ dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors);
+ /*
+ * fill in all the output members
+ */
+ hdr->device_status = rq->errors & 0xff;
+ hdr->transport_status = host_byte(rq->errors);
+ hdr->driver_status = driver_byte(rq->errors);
+ hdr->info = 0;
+ if (hdr->device_status || hdr->transport_status || hdr->driver_status)
+ hdr->info |= SG_INFO_CHECK;
+ hdr->response_len = 0;
+
+ if (rq->sense_len && hdr->response) {
+ int len = min_t(unsigned int, hdr->max_response_len,
+ rq->sense_len);
+
+ ret = copy_to_user((void __user *)(unsigned long)hdr->response,
+ rq->sense, len);
+ if (!ret)
+ hdr->response_len = len;
+ else
+ ret = -EFAULT;
+ }
+
+ if (rq->next_rq) {
+ hdr->dout_resid = rq->resid_len;
+ hdr->din_resid = rq->next_rq->resid_len;
+ blk_rq_unmap_user(bidi_bio);
+ blk_put_request(rq->next_rq);
+ } else if (rq_data_dir(rq) == READ)
+ hdr->din_resid = rq->resid_len;
+ else
+ hdr->dout_resid = rq->resid_len;
+
+ /*
+ * If the request generated a negative error number, return it
+ * (providing we aren't already returning an error); if it's
+ * just a protocol response (i.e. non negative), that gets
+ * processed above.
+ */
+ if (!ret && rq->errors < 0)
+ ret = rq->errors;
+
+ blk_rq_unmap_user(bio);
+ if (rq->cmd != rq->__cmd)
+ kfree(rq->cmd);
+ blk_put_request(rq);
+
+ return ret;
+}
+
+static bool bsg_complete(struct bsg_device *bd)
+{
+ bool ret = false;
+ bool spin;
+
+ do {
+ spin_lock_irq(&bd->lock);
+
+ BUG_ON(bd->done_cmds > bd->queued_cmds);
+
+ /*
+ * All commands consumed.
+ */
+ if (bd->done_cmds == bd->queued_cmds)
+ ret = true;
+
+ spin = !test_bit(BSG_F_BLOCK, &bd->flags);
+
+ spin_unlock_irq(&bd->lock);
+ } while (!ret && spin);
+
+ return ret;
+}
+
+static int bsg_complete_all_commands(struct bsg_device *bd)
+{
+ struct bsg_command *bc;
+ int ret, tret;
+
+ dprintk("%s: entered\n", bd->name);
+
+ /*
+ * wait for all commands to complete
+ */
+ io_wait_event(bd->wq_done, bsg_complete(bd));
+
+ /*
+ * discard done commands
+ */
+ ret = 0;
+ do {
+ spin_lock_irq(&bd->lock);
+ if (!bd->queued_cmds) {
+ spin_unlock_irq(&bd->lock);
+ break;
+ }
+ spin_unlock_irq(&bd->lock);
+
+ bc = bsg_get_done_cmd(bd);
+ if (IS_ERR(bc))
+ break;
+
+ tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
+ bc->bidi_bio);
+ if (!ret)
+ ret = tret;
+
+ bsg_free_command(bc);
+ } while (1);
+
+ return ret;
+}
+
+static int
+__bsg_read(char __user *buf, size_t count, 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_v4))
+ return -EINVAL;
+
+ ret = 0;
+ nr_commands = count / sizeof(struct sg_io_v4);
+ while (nr_commands) {
+ bc = bsg_get_done_cmd(bd);
+ 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_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
+ bc->bidi_bio);
+
+ if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
+ ret = -EFAULT;
+
+ bsg_free_command(bc);
+
+ if (ret)
+ break;
+
+ buf += sizeof(struct sg_io_v4);
+ *bytes_read += sizeof(struct sg_io_v4);
+ 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);
+}
+
+/*
+ * Check if the error is a "real" error that we should return.
+ */
+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 %Zd bytes\n", bd->name, count);
+
+ bsg_set_block(bd, file);
+
+ bytes_read = 0;
+ ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
+ *ppos = bytes_read;
+
+ if (!bytes_read || err_block_err(ret))
+ bytes_read = ret;
+
+ return bytes_read;
+}
+
+static int __bsg_write(struct bsg_device *bd, const char __user *buf,
+ size_t count, ssize_t *bytes_written,
+ fmode_t has_write_perm)
+{
+ struct bsg_command *bc;
+ struct request *rq;
+ int ret, nr_commands;
+
+ if (count % sizeof(struct sg_io_v4))
+ return -EINVAL;
+
+ nr_commands = count / sizeof(struct sg_io_v4);
+ rq = NULL;
+ bc = NULL;
+ ret = 0;
+ while (nr_commands) {
+ struct request_queue *q = bd->queue;
+
+ bc = bsg_alloc_command(bd);
+ if (IS_ERR(bc)) {
+ ret = PTR_ERR(bc);
+ bc = NULL;
+ break;
+ }
+
+ 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, &bc->hdr, has_write_perm, bc->sense);
+ 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_v4);
+ *bytes_written += sizeof(struct sg_io_v4);
+ }
+
+ 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_written;
+ int ret;
+
+ dprintk("%s: write %Zd bytes\n", bd->name, count);
+
+ bsg_set_block(bd, file);
+
+ bytes_written = 0;
+ ret = __bsg_write(bd, buf, count, &bytes_written,
+ file->f_mode & FMODE_WRITE);
+
+ *ppos = bytes_written;
+
+ /*
+ * return bytes written on non-fatal errors
+ */
+ if (!bytes_written || err_block_err(ret))
+ bytes_written = ret;
+
+ dprintk("%s: returning %Zd\n", bd->name, bytes_written);
+ return bytes_written;
+}
+
+static struct bsg_device *bsg_alloc_device(void)
+{
+ struct bsg_device *bd;
+
+ bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
+ if (unlikely(!bd))
+ return NULL;
+
+ spin_lock_init(&bd->lock);
+
+ bd->max_queue = BSG_DEFAULT_CMDS;
+
+ 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;
+}
+
+static void bsg_kref_release_function(struct kref *kref)
+{
+ struct bsg_class_device *bcd =
+ container_of(kref, struct bsg_class_device, ref);
+ struct device *parent = bcd->parent;
+
+ if (bcd->release)
+ bcd->release(bcd->parent);
+
+ put_device(parent);
+}
+
+static int bsg_put_device(struct bsg_device *bd)
+{
+ int ret = 0, do_free;
+ struct request_queue *q = bd->queue;
+
+ mutex_lock(&bsg_mutex);
+
+ do_free = atomic_dec_and_test(&bd->ref_count);
+ if (!do_free) {
+ mutex_unlock(&bsg_mutex);
+ goto out;
+ }
+
+ hlist_del(&bd->dev_list);
+ mutex_unlock(&bsg_mutex);
+
+ 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);
+
+ kfree(bd);
+out:
+ kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
+ if (do_free)
+ blk_put_queue(q);
+ return ret;
+}
+
+static struct bsg_device *bsg_add_device(struct inode *inode,
+ struct request_queue *rq,
+ struct file *file)
+{
+ struct bsg_device *bd;
+#ifdef BSG_DEBUG
+ unsigned char buf[32];
+#endif
+ if (!blk_get_queue(rq))
+ return ERR_PTR(-ENXIO);
+
+ bd = bsg_alloc_device();
+ if (!bd) {
+ blk_put_queue(rq);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ bd->queue = rq;
+
+ bsg_set_block(bd, file);
+
+ atomic_set(&bd->ref_count, 1);
+ mutex_lock(&bsg_mutex);
+ hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
+
+ strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
+ dprintk("bound to <%s>, max queue %d\n",
+ format_dev_t(buf, inode->i_rdev), bd->max_queue);
+
+ mutex_unlock(&bsg_mutex);
+ return bd;
+}
+
+static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
+{
+ struct bsg_device *bd;
+
+ mutex_lock(&bsg_mutex);
+
+ hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
+ if (bd->queue == q) {
+ atomic_inc(&bd->ref_count);
+ goto found;
+ }
+ }
+ bd = NULL;
+found:
+ mutex_unlock(&bsg_mutex);
+ return bd;
+}
+
+static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
+{
+ struct bsg_device *bd;
+ struct bsg_class_device *bcd;
+
+ /*
+ * find the class device
+ */
+ mutex_lock(&bsg_mutex);
+ bcd = idr_find(&bsg_minor_idr, iminor(inode));
+ if (bcd)
+ kref_get(&bcd->ref);
+ mutex_unlock(&bsg_mutex);
+
+ if (!bcd)
+ return ERR_PTR(-ENODEV);
+
+ bd = __bsg_get_device(iminor(inode), bcd->queue);
+ if (bd)
+ return bd;
+
+ bd = bsg_add_device(inode, bcd->queue, file);
+ if (IS_ERR(bd))
+ kref_put(&bcd->ref, bsg_kref_release_function);
+
+ return bd;
+}
+
+static int bsg_open(struct inode *inode, struct file *file)
+{
+ struct bsg_device *bd;
+
+ 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 long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct bsg_device *bd = file->private_data;
+ int __user *uarg = (int __user *) arg;
+ int ret;
+
+ 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 < 1)
+ return -EINVAL;
+
+ spin_lock_irq(&bd->lock);
+ bd->max_queue = queue;
+ spin_unlock_irq(&bd->lock);
+ 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 SCSI_IOCTL_SEND_COMMAND: {
+ void __user *uarg = (void __user *) arg;
+ return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
+ }
+ case SG_IO: {
+ struct request *rq;
+ struct bio *bio, *bidi_bio = NULL;
+ struct sg_io_v4 hdr;
+ int at_head;
+ u8 sense[SCSI_SENSE_BUFFERSIZE];
+
+ if (copy_from_user(&hdr, uarg, sizeof(hdr)))
+ return -EFAULT;
+
+ rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense);
+ if (IS_ERR(rq))
+ return PTR_ERR(rq);
+
+ bio = rq->bio;
+ if (rq->next_rq)
+ bidi_bio = rq->next_rq->bio;
+
+ at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
+ blk_execute_rq(bd->queue, NULL, rq, at_head);
+ ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
+
+ if (copy_to_user(uarg, &hdr, sizeof(hdr)))
+ return -EFAULT;
+
+ return ret;
+ }
+ /*
+ * block device ioctls
+ */
+ default:
+#if 0
+ return ioctl_by_bdev(bd->bdev, cmd, arg);
+#else
+ return -ENOTTY;
+#endif
+ }
+}
+
+static const struct file_operations bsg_fops = {
+ .read = bsg_read,
+ .write = bsg_write,
+ .poll = bsg_poll,
+ .open = bsg_open,
+ .release = bsg_release,
+ .unlocked_ioctl = bsg_ioctl,
+ .owner = THIS_MODULE,
+ .llseek = default_llseek,
+};
+
+void bsg_unregister_queue(struct request_queue *q)
+{
+ struct bsg_class_device *bcd = &q->bsg_dev;
+
+ if (!bcd->class_dev)
+ return;
+
+ mutex_lock(&bsg_mutex);
+ idr_remove(&bsg_minor_idr, bcd->minor);
+ if (q->kobj.sd)
+ sysfs_remove_link(&q->kobj, "bsg");
+ device_unregister(bcd->class_dev);
+ bcd->class_dev = NULL;
+ kref_put(&bcd->ref, bsg_kref_release_function);
+ mutex_unlock(&bsg_mutex);
+}
+EXPORT_SYMBOL_GPL(bsg_unregister_queue);
+
+int bsg_register_queue(struct request_queue *q, struct device *parent,
+ const char *name, void (*release)(struct device *))
+{
+ struct bsg_class_device *bcd;
+ dev_t dev;
+ int ret;
+ struct device *class_dev = NULL;
+ const char *devname;
+
+ if (name)
+ devname = name;
+ else
+ devname = dev_name(parent);
+
+ /*
+ * we need a proper transport to send commands, not a stacked device
+ */
+ if (!queue_is_rq_based(q))
+ return 0;
+
+ bcd = &q->bsg_dev;
+ memset(bcd, 0, sizeof(*bcd));
+
+ mutex_lock(&bsg_mutex);
+
+ ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
+ if (ret < 0) {
+ if (ret == -ENOSPC) {
+ printk(KERN_ERR "bsg: too many bsg devices\n");
+ ret = -EINVAL;
+ }
+ goto unlock;
+ }
+
+ bcd->minor = ret;
+ bcd->queue = q;
+ bcd->parent = get_device(parent);
+ bcd->release = release;
+ kref_init(&bcd->ref);
+ dev = MKDEV(bsg_major, bcd->minor);
+ class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname);
+ if (IS_ERR(class_dev)) {
+ ret = PTR_ERR(class_dev);
+ goto put_dev;
+ }
+ bcd->class_dev = class_dev;
+
+ if (q->kobj.sd) {
+ ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
+ if (ret)
+ goto unregister_class_dev;
+ }
+
+ mutex_unlock(&bsg_mutex);
+ return 0;
+
+unregister_class_dev:
+ device_unregister(class_dev);
+put_dev:
+ put_device(parent);
+ idr_remove(&bsg_minor_idr, bcd->minor);
+unlock:
+ mutex_unlock(&bsg_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(bsg_register_queue);
+
+static struct cdev bsg_cdev;
+
+static char *bsg_devnode(struct device *dev, umode_t *mode)
+{
+ return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
+}
+
+static int __init bsg_init(void)
+{
+ int ret, i;
+ dev_t devid;
+
+ bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
+ sizeof(struct bsg_command), 0, 0, NULL);
+ if (!bsg_cmd_cachep) {
+ printk(KERN_ERR "bsg: failed creating slab cache\n");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
+ INIT_HLIST_HEAD(&bsg_device_list[i]);
+
+ bsg_class = class_create(THIS_MODULE, "bsg");
+ if (IS_ERR(bsg_class)) {
+ ret = PTR_ERR(bsg_class);
+ goto destroy_kmemcache;
+ }
+ bsg_class->devnode = bsg_devnode;
+
+ ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
+ if (ret)
+ goto destroy_bsg_class;
+
+ bsg_major = MAJOR(devid);
+
+ cdev_init(&bsg_cdev, &bsg_fops);
+ ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
+ if (ret)
+ goto unregister_chrdev;
+
+ printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
+ " loaded (major %d)\n", bsg_major);
+ return 0;
+unregister_chrdev:
+ unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
+destroy_bsg_class:
+ class_destroy(bsg_class);
+destroy_kmemcache:
+ kmem_cache_destroy(bsg_cmd_cachep);
+ return ret;
+}
+
+MODULE_AUTHOR("Jens Axboe");
+MODULE_DESCRIPTION(BSG_DESCRIPTION);
+MODULE_LICENSE("GPL");
+
+device_initcall(bsg_init);
Code Review / kvmfornfv.git / blobdiff