]> nv-tegra.nvidia Code Review - linux-2.6.git/blobdiff - drivers/block/nbd.c
nbd: rename the nbd_device variable from lo to nbd
[linux-2.6.git] / drivers / block / nbd.c
index 485345c8e6320199782aa01cdcd285b54e177482..864db101ad2db555c518e5281f3e558eb2bfdae7 100644 (file)
@@ -4,42 +4,12 @@
  * Note that you can not swap over this thing, yet. Seems to work but
  * deadlocks sometimes - you can not swap over TCP in general.
  * 
- * Copyright 1997-2000 Pavel Machek <pavel@ucw.cz>
+ * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
  * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
  *
- * (part of code stolen from loop.c)
+ * This file is released under GPLv2 or later.
  *
- * 97-3-25 compiled 0-th version, not yet tested it 
- *   (it did not work, BTW) (later that day) HEY! it works!
- *   (bit later) hmm, not that much... 2:00am next day:
- *   yes, it works, but it gives something like 50kB/sec
- * 97-4-01 complete rewrite to make it possible for many requests at 
- *   once to be processed
- * 97-4-11 Making protocol independent of endianity etc.
- * 97-9-13 Cosmetic changes
- * 98-5-13 Attempt to make 64-bit-clean on 64-bit machines
- * 99-1-11 Attempt to make 64-bit-clean on 32-bit machines <ankry@mif.pg.gda.pl>
- * 01-2-27 Fix to store proper blockcount for kernel (calculated using
- *   BLOCK_SIZE_BITS, not device blocksize) <aga@permonline.ru>
- * 01-3-11 Make nbd work with new Linux block layer code. It now supports
- *   plugging like all the other block devices. Also added in MSG_MORE to
- *   reduce number of partial TCP segments sent. <steve@chygwyn.com>
- * 01-12-6 Fix deadlock condition by making queue locks independent of
- *   the transmit lock. <steve@chygwyn.com>
- * 02-10-11 Allow hung xmit to be aborted via SIGKILL & various fixes.
- *   <Paul.Clements@SteelEye.com> <James.Bottomley@SteelEye.com>
- * 03-06-22 Make nbd work with new linux 2.5 block layer design. This fixes
- *   memory corruption from module removal and possible memory corruption
- *   from sending/receiving disk data. <ldl@aros.net>
- * 03-06-23 Cosmetic changes. <ldl@aros.net>
- * 03-06-23 Enhance diagnostics support. <ldl@aros.net>
- * 03-06-24 Remove unneeded blksize_bits field from nbd_device struct.
- *   <ldl@aros.net>
- * 03-06-24 Cleanup PARANOIA usage & code. <ldl@aros.net>
- * 04-02-19 Remove PARANOIA, plus various cleanups (Paul Clements)
- * possible FIXME: make set_sock / set_blksize / set_size / do_it one syscall
- * why not: would need access_ok and friends, would share yet another
- *          structure with userland
+ * (part of code stolen from loop.c)
  */
 
 #include <linux/major.h>
 #include <linux/errno.h>
 #include <linux/file.h>
 #include <linux/ioctl.h>
+#include <linux/mutex.h>
+#include <linux/compiler.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
 #include <net/sock.h>
-
-#include <linux/devfs_fs_kernel.h>
+#include <linux/net.h>
+#include <linux/kthread.h>
 
 #include <asm/uaccess.h>
+#include <asm/system.h>
 #include <asm/types.h>
 
 #include <linux/nbd.h>
 
-#define LO_MAGIC 0x68797548
+#define NBD_MAGIC 0x68797548
 
 #ifdef NDEBUG
 #define dprintk(flags, fmt...)
 #define DBG_RX          0x0200
 #define DBG_TX          0x0400
 static unsigned int debugflags;
-static unsigned int nbds_max = 16;
 #endif /* NDEBUG */
 
-static struct nbd_device nbd_dev[MAX_NBD];
+static unsigned int nbds_max = 16;
+static struct nbd_device *nbd_dev;
+static int max_part;
 
 /*
  * Use just one lock (or at most 1 per NIC). Two arguments for this:
@@ -127,40 +104,69 @@ static const char *nbdcmd_to_ascii(int cmd)
 
 static void nbd_end_request(struct request *req)
 {
-       int uptodate = (req->errors == 0) ? 1 : 0;
-       request_queue_t *q = req->q;
+       int error = req->errors ? -EIO : 0;
+       struct request_queue *q = req->q;
        unsigned long flags;
 
        dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
-                       req, uptodate? "done": "failed");
+                       req, error ? "failed" : "done");
 
        spin_lock_irqsave(q->queue_lock, flags);
-       if (!end_that_request_first(req, uptodate, req->nr_sectors)) {
-               end_that_request_last(req, uptodate);
-       }
+       __blk_end_request_all(req, error);
        spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
+static void sock_shutdown(struct nbd_device *nbd, int lock)
+{
+       /* Forcibly shutdown the socket causing all listeners
+        * to error
+        *
+        * FIXME: This code is duplicated from sys_shutdown, but
+        * there should be a more generic interface rather than
+        * calling socket ops directly here */
+       if (lock)
+               mutex_lock(&nbd->tx_lock);
+       if (nbd->sock) {
+               dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
+               kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
+               nbd->sock = NULL;
+       }
+       if (lock)
+               mutex_unlock(&nbd->tx_lock);
+}
+
+static void nbd_xmit_timeout(unsigned long arg)
+{
+       struct task_struct *task = (struct task_struct *)arg;
+
+       printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n",
+               task->comm, task->pid);
+       force_sig(SIGKILL, task);
+}
+
 /*
  *  Send or receive packet.
  */
-static int sock_xmit(struct socket *sock, int send, void *buf, int size,
+static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
                int msg_flags)
 {
+       struct socket *sock = nbd->sock;
        int result;
        struct msghdr msg;
        struct kvec iov;
-       unsigned long flags;
-       sigset_t oldset;
+       sigset_t blocked, oldset;
+
+       if (unlikely(!sock)) {
+               dev_err(disk_to_dev(nbd->disk),
+                       "Attempted %s on closed socket in sock_xmit\n",
+                       (send ? "send" : "recv"));
+               return -EINVAL;
+       }
 
        /* Allow interception of SIGKILL only
         * Don't allow other signals to interrupt the transmission */
-       spin_lock_irqsave(&current->sighand->siglock, flags);
-       oldset = current->blocked;
-       sigfillset(&current->blocked);
-       sigdelsetmask(&current->blocked, sigmask(SIGKILL));
-       recalc_sigpending();
-       spin_unlock_irqrestore(&current->sighand->siglock, flags);
+       siginitsetinv(&blocked, sigmask(SIGKILL));
+       sigprocmask(SIG_SETMASK, &blocked, &oldset);
 
        do {
                sock->sk->sk_allocation = GFP_NOIO;
@@ -170,22 +176,32 @@ static int sock_xmit(struct socket *sock, int send, void *buf, int size,
                msg.msg_namelen = 0;
                msg.msg_control = NULL;
                msg.msg_controllen = 0;
-               msg.msg_namelen = 0;
                msg.msg_flags = msg_flags | MSG_NOSIGNAL;
 
-               if (send)
+               if (send) {
+                       struct timer_list ti;
+
+                       if (nbd->xmit_timeout) {
+                               init_timer(&ti);
+                               ti.function = nbd_xmit_timeout;
+                               ti.data = (unsigned long)current;
+                               ti.expires = jiffies + nbd->xmit_timeout;
+                               add_timer(&ti);
+                       }
                        result = kernel_sendmsg(sock, &msg, &iov, 1, size);
-               else
-                       result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0);
+                       if (nbd->xmit_timeout)
+                               del_timer_sync(&ti);
+               } else
+                       result = kernel_recvmsg(sock, &msg, &iov, 1, size,
+                                               msg.msg_flags);
 
                if (signal_pending(current)) {
                        siginfo_t info;
-                       spin_lock_irqsave(&current->sighand->siglock, flags);
                        printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
-                               current->pid, current->comm, 
-                               dequeue_signal(current, &current->blocked, &info));
-                       spin_unlock_irqrestore(&current->sighand->siglock, flags);
+                               task_pid_nr(current), current->comm,
+                               dequeue_signal_lock(current, &current->blocked, &info));
                        result = -EINTR;
+                       sock_shutdown(nbd, !send);
                        break;
                }
 
@@ -198,436 +214,518 @@ static int sock_xmit(struct socket *sock, int send, void *buf, int size,
                buf += result;
        } while (size > 0);
 
-       spin_lock_irqsave(&current->sighand->siglock, flags);
-       current->blocked = oldset;
-       recalc_sigpending();
-       spin_unlock_irqrestore(&current->sighand->siglock, flags);
+       sigprocmask(SIG_SETMASK, &oldset, NULL);
 
        return result;
 }
 
-static inline int sock_send_bvec(struct socket *sock, struct bio_vec *bvec,
+static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec,
                int flags)
 {
        int result;
        void *kaddr = kmap(bvec->bv_page);
-       result = sock_xmit(sock, 1, kaddr + bvec->bv_offset, bvec->bv_len,
-                       flags);
+       result = sock_xmit(nbd, 1, kaddr + bvec->bv_offset,
+                          bvec->bv_len, flags);
        kunmap(bvec->bv_page);
        return result;
 }
 
-static int nbd_send_req(struct nbd_device *lo, struct request *req)
+/* always call with the tx_lock held */
+static int nbd_send_req(struct nbd_device *nbd, struct request *req)
 {
-       int result, i, flags;
+       int result, flags;
        struct nbd_request request;
-       unsigned long size = req->nr_sectors << 9;
-       struct socket *sock = lo->sock;
+       unsigned long size = blk_rq_bytes(req);
 
        request.magic = htonl(NBD_REQUEST_MAGIC);
        request.type = htonl(nbd_cmd(req));
-       request.from = cpu_to_be64((u64) req->sector << 9);
+       request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
        request.len = htonl(size);
        memcpy(request.handle, &req, sizeof(req));
 
-       down(&lo->tx_lock);
-
-       if (!sock || !lo->sock) {
-               printk(KERN_ERR "%s: Attempted send on closed socket\n",
-                               lo->disk->disk_name);
-               goto error_out;
-       }
-
-       dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n",
-                       lo->disk->disk_name, req,
+       dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n",
+                       nbd->disk->disk_name, req,
                        nbdcmd_to_ascii(nbd_cmd(req)),
-                       (unsigned long long)req->sector << 9,
-                       req->nr_sectors << 9);
-       result = sock_xmit(sock, 1, &request, sizeof(request),
-                       (nbd_cmd(req) == NBD_CMD_WRITE)? MSG_MORE: 0);
+                       (unsigned long long)blk_rq_pos(req) << 9,
+                       blk_rq_bytes(req));
+       result = sock_xmit(nbd, 1, &request, sizeof(request),
+                       (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0);
        if (result <= 0) {
-               printk(KERN_ERR "%s: Send control failed (result %d)\n",
-                               lo->disk->disk_name, result);
+               dev_err(disk_to_dev(nbd->disk),
+                       "Send control failed (result %d)\n", result);
                goto error_out;
        }
 
        if (nbd_cmd(req) == NBD_CMD_WRITE) {
-               struct bio *bio;
+               struct req_iterator iter;
+               struct bio_vec *bvec;
                /*
                 * we are really probing at internals to determine
                 * whether to set MSG_MORE or not...
                 */
-               rq_for_each_bio(bio, req) {
-                       struct bio_vec *bvec;
-                       bio_for_each_segment(bvec, bio, i) {
-                               flags = 0;
-                               if ((i < (bio->bi_vcnt - 1)) || bio->bi_next)
-                                       flags = MSG_MORE;
-                               dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
-                                               lo->disk->disk_name, req,
-                                               bvec->bv_len);
-                               result = sock_send_bvec(sock, bvec, flags);
-                               if (result <= 0) {
-                                       printk(KERN_ERR "%s: Send data failed (result %d)\n",
-                                                       lo->disk->disk_name,
-                                                       result);
-                                       goto error_out;
-                               }
+               rq_for_each_segment(bvec, req, iter) {
+                       flags = 0;
+                       if (!rq_iter_last(req, iter))
+                               flags = MSG_MORE;
+                       dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
+                                       nbd->disk->disk_name, req, bvec->bv_len);
+                       result = sock_send_bvec(nbd, bvec, flags);
+                       if (result <= 0) {
+                               dev_err(disk_to_dev(nbd->disk),
+                                       "Send data failed (result %d)\n",
+                                       result);
+                               goto error_out;
                        }
                }
        }
-       up(&lo->tx_lock);
        return 0;
 
 error_out:
-       up(&lo->tx_lock);
-       return 1;
+       return -EIO;
 }
 
-static struct request *nbd_find_request(struct nbd_device *lo, char *handle)
+static struct request *nbd_find_request(struct nbd_device *nbd,
+                                       struct request *xreq)
 {
-       struct request *req;
-       struct list_head *tmp;
-       struct request *xreq;
+       struct request *req, *tmp;
+       int err;
 
-       memcpy(&xreq, handle, sizeof(xreq));
+       err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq);
+       if (unlikely(err))
+               goto out;
 
-       spin_lock(&lo->queue_lock);
-       list_for_each(tmp, &lo->queue_head) {
-               req = list_entry(tmp, struct request, queuelist);
+       spin_lock(&nbd->queue_lock);
+       list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) {
                if (req != xreq)
                        continue;
                list_del_init(&req->queuelist);
-               spin_unlock(&lo->queue_lock);
+               spin_unlock(&nbd->queue_lock);
                return req;
        }
-       spin_unlock(&lo->queue_lock);
-       return NULL;
+       spin_unlock(&nbd->queue_lock);
+
+       err = -ENOENT;
+
+out:
+       return ERR_PTR(err);
 }
 
-static inline int sock_recv_bvec(struct socket *sock, struct bio_vec *bvec)
+static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec)
 {
        int result;
        void *kaddr = kmap(bvec->bv_page);
-       result = sock_xmit(sock, 0, kaddr + bvec->bv_offset, bvec->bv_len,
+       result = sock_xmit(nbd, 0, kaddr + bvec->bv_offset, bvec->bv_len,
                        MSG_WAITALL);
        kunmap(bvec->bv_page);
        return result;
 }
 
 /* NULL returned = something went wrong, inform userspace */
-static struct request *nbd_read_stat(struct nbd_device *lo)
+static struct request *nbd_read_stat(struct nbd_device *nbd)
 {
        int result;
        struct nbd_reply reply;
        struct request *req;
-       struct socket *sock = lo->sock;
 
        reply.magic = 0;
-       result = sock_xmit(sock, 0, &reply, sizeof(reply), MSG_WAITALL);
+       result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL);
        if (result <= 0) {
-               printk(KERN_ERR "%s: Receive control failed (result %d)\n",
-                               lo->disk->disk_name, result);
-               goto harderror;
-       }
-       req = nbd_find_request(lo, reply.handle);
-       if (req == NULL) {
-               printk(KERN_ERR "%s: Unexpected reply (%p)\n",
-                               lo->disk->disk_name, reply.handle);
-               result = -EBADR;
+               dev_err(disk_to_dev(nbd->disk),
+                       "Receive control failed (result %d)\n", result);
                goto harderror;
        }
 
        if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
-               printk(KERN_ERR "%s: Wrong magic (0x%lx)\n",
-                               lo->disk->disk_name,
+               dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
                                (unsigned long)ntohl(reply.magic));
                result = -EPROTO;
                goto harderror;
        }
+
+       req = nbd_find_request(nbd, *(struct request **)reply.handle);
+       if (IS_ERR(req)) {
+               result = PTR_ERR(req);
+               if (result != -ENOENT)
+                       goto harderror;
+
+               dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n",
+                       reply.handle);
+               result = -EBADR;
+               goto harderror;
+       }
+
        if (ntohl(reply.error)) {
-               printk(KERN_ERR "%s: Other side returned error (%d)\n",
-                               lo->disk->disk_name, ntohl(reply.error));
+               dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
+                       ntohl(reply.error));
                req->errors++;
                return req;
        }
 
        dprintk(DBG_RX, "%s: request %p: got reply\n",
-                       lo->disk->disk_name, req);
+                       nbd->disk->disk_name, req);
        if (nbd_cmd(req) == NBD_CMD_READ) {
-               int i;
-               struct bio *bio;
-               rq_for_each_bio(bio, req) {
-                       struct bio_vec *bvec;
-                       bio_for_each_segment(bvec, bio, i) {
-                               result = sock_recv_bvec(sock, bvec);
-                               if (result <= 0) {
-                                       printk(KERN_ERR "%s: Receive data failed (result %d)\n",
-                                                       lo->disk->disk_name,
-                                                       result);
-                                       goto harderror;
-                               }
-                               dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
-                                       lo->disk->disk_name, req, bvec->bv_len);
+               struct req_iterator iter;
+               struct bio_vec *bvec;
+
+               rq_for_each_segment(bvec, req, iter) {
+                       result = sock_recv_bvec(nbd, bvec);
+                       if (result <= 0) {
+                               dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
+                                       result);
+                               req->errors++;
+                               return req;
                        }
+                       dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
+                               nbd->disk->disk_name, req, bvec->bv_len);
                }
        }
        return req;
 harderror:
-       lo->harderror = result;
+       nbd->harderror = result;
        return NULL;
 }
 
-static void nbd_do_it(struct nbd_device *lo)
+static ssize_t pid_show(struct device *dev,
+                       struct device_attribute *attr, char *buf)
+{
+       struct gendisk *disk = dev_to_disk(dev);
+
+       return sprintf(buf, "%ld\n",
+               (long) ((struct nbd_device *)disk->private_data)->pid);
+}
+
+static struct device_attribute pid_attr = {
+       .attr = { .name = "pid", .mode = S_IRUGO},
+       .show = pid_show,
+};
+
+static int nbd_do_it(struct nbd_device *nbd)
 {
        struct request *req;
+       int ret;
 
-       BUG_ON(lo->magic != LO_MAGIC);
+       BUG_ON(nbd->magic != NBD_MAGIC);
 
-       while ((req = nbd_read_stat(lo)) != NULL)
+       nbd->pid = task_pid_nr(current);
+       ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
+       if (ret) {
+               dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
+               nbd->pid = 0;
+               return ret;
+       }
+
+       while ((req = nbd_read_stat(nbd)) != NULL)
                nbd_end_request(req);
-       return;
+
+       device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
+       nbd->pid = 0;
+       return 0;
 }
 
-static void nbd_clear_que(struct nbd_device *lo)
+static void nbd_clear_que(struct nbd_device *nbd)
 {
        struct request *req;
 
-       BUG_ON(lo->magic != LO_MAGIC);
+       BUG_ON(nbd->magic != NBD_MAGIC);
+
+       /*
+        * Because we have set nbd->sock to NULL under the tx_lock, all
+        * modifications to the list must have completed by now.  For
+        * the same reason, the active_req must be NULL.
+        *
+        * As a consequence, we don't need to take the spin lock while
+        * purging the list here.
+        */
+       BUG_ON(nbd->sock);
+       BUG_ON(nbd->active_req);
+
+       while (!list_empty(&nbd->queue_head)) {
+               req = list_entry(nbd->queue_head.next, struct request,
+                                queuelist);
+               list_del_init(&req->queuelist);
+               req->errors++;
+               nbd_end_request(req);
+       }
+}
+
 
-       do {
-               req = NULL;
-               spin_lock(&lo->queue_lock);
-               if (!list_empty(&lo->queue_head)) {
-                       req = list_entry(lo->queue_head.next, struct request, queuelist);
-                       list_del_init(&req->queuelist);
-               }
-               spin_unlock(&lo->queue_lock);
-               if (req) {
-                       req->errors++;
-                       nbd_end_request(req);
+static void nbd_handle_req(struct nbd_device *nbd, struct request *req)
+{
+       if (req->cmd_type != REQ_TYPE_FS)
+               goto error_out;
+
+       nbd_cmd(req) = NBD_CMD_READ;
+       if (rq_data_dir(req) == WRITE) {
+               nbd_cmd(req) = NBD_CMD_WRITE;
+               if (nbd->flags & NBD_READ_ONLY) {
+                       dev_err(disk_to_dev(nbd->disk),
+                               "Write on read-only\n");
+                       goto error_out;
                }
-       } while (req);
+       }
+
+       req->errors = 0;
+
+       mutex_lock(&nbd->tx_lock);
+       if (unlikely(!nbd->sock)) {
+               mutex_unlock(&nbd->tx_lock);
+               dev_err(disk_to_dev(nbd->disk),
+                       "Attempted send on closed socket\n");
+               goto error_out;
+       }
+
+       nbd->active_req = req;
+
+       if (nbd_send_req(nbd, req) != 0) {
+               dev_err(disk_to_dev(nbd->disk), "Request send failed\n");
+               req->errors++;
+               nbd_end_request(req);
+       } else {
+               spin_lock(&nbd->queue_lock);
+               list_add(&req->queuelist, &nbd->queue_head);
+               spin_unlock(&nbd->queue_lock);
+       }
+
+       nbd->active_req = NULL;
+       mutex_unlock(&nbd->tx_lock);
+       wake_up_all(&nbd->active_wq);
+
+       return;
+
+error_out:
+       req->errors++;
+       nbd_end_request(req);
+}
+
+static int nbd_thread(void *data)
+{
+       struct nbd_device *nbd = data;
+       struct request *req;
+
+       set_user_nice(current, -20);
+       while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) {
+               /* wait for something to do */
+               wait_event_interruptible(nbd->waiting_wq,
+                                        kthread_should_stop() ||
+                                        !list_empty(&nbd->waiting_queue));
+
+               /* extract request */
+               if (list_empty(&nbd->waiting_queue))
+                       continue;
+
+               spin_lock_irq(&nbd->queue_lock);
+               req = list_entry(nbd->waiting_queue.next, struct request,
+                                queuelist);
+               list_del_init(&req->queuelist);
+               spin_unlock_irq(&nbd->queue_lock);
+
+               /* handle request */
+               nbd_handle_req(nbd, req);
+       }
+       return 0;
 }
 
 /*
  * We always wait for result of write, for now. It would be nice to make it optional
  * in future
- * if ((req->cmd == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) 
+ * if ((rq_data_dir(req) == WRITE) && (nbd->flags & NBD_WRITE_NOCHK))
  *   { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); }
  */
 
-static void do_nbd_request(request_queue_t * q)
+static void do_nbd_request(struct request_queue *q)
 {
        struct request *req;
        
-       while ((req = elv_next_request(q)) != NULL) {
-               struct nbd_device *lo;
-
-               blkdev_dequeue_request(req);
-               dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%lx)\n",
-                               req->rq_disk->disk_name, req, req->flags);
+       while ((req = blk_fetch_request(q)) != NULL) {
+               struct nbd_device *nbd;
 
-               if (!(req->flags & REQ_CMD))
-                       goto error_out;
-
-               lo = req->rq_disk->private_data;
-
-               BUG_ON(lo->magic != LO_MAGIC);
+               spin_unlock_irq(q->queue_lock);
 
-               if (!lo->file) {
-                       printk(KERN_ERR "%s: Request when not-ready\n",
-                                       lo->disk->disk_name);
-                       goto error_out;
-               }
-               nbd_cmd(req) = NBD_CMD_READ;
-               if (rq_data_dir(req) == WRITE) {
-                       nbd_cmd(req) = NBD_CMD_WRITE;
-                       if (lo->flags & NBD_READ_ONLY) {
-                               printk(KERN_ERR "%s: Write on read-only\n",
-                                               lo->disk->disk_name);
-                               goto error_out;
-                       }
-               }
+               dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n",
+                               req->rq_disk->disk_name, req, req->cmd_type);
 
-               req->errors = 0;
-               spin_unlock_irq(q->queue_lock);
+               nbd = req->rq_disk->private_data;
 
-               spin_lock(&lo->queue_lock);
+               BUG_ON(nbd->magic != NBD_MAGIC);
 
-               if (!lo->file) {
-                       spin_unlock(&lo->queue_lock);
-                       printk(KERN_ERR "%s: failed between accept and semaphore, file lost\n",
-                                       lo->disk->disk_name);
+               if (unlikely(!nbd->sock)) {
+                       dev_err(disk_to_dev(nbd->disk),
+                               "Attempted send on closed socket\n");
                        req->errors++;
                        nbd_end_request(req);
                        spin_lock_irq(q->queue_lock);
                        continue;
                }
 
-               list_add(&req->queuelist, &lo->queue_head);
-               spin_unlock(&lo->queue_lock);
+               spin_lock_irq(&nbd->queue_lock);
+               list_add_tail(&req->queuelist, &nbd->waiting_queue);
+               spin_unlock_irq(&nbd->queue_lock);
 
-               if (nbd_send_req(lo, req) != 0) {
-                       printk(KERN_ERR "%s: Request send failed\n",
-                                       lo->disk->disk_name);
-                       if (nbd_find_request(lo, (char *)&req) != NULL) {
-                               /* we still own req */
-                               req->errors++;
-                               nbd_end_request(req);
-                       } else /* we're racing with nbd_clear_que */
-                               printk(KERN_DEBUG "nbd: can't find req\n");
-               }
+               wake_up(&nbd->waiting_wq);
 
                spin_lock_irq(q->queue_lock);
-               continue;
-
-error_out:
-               req->errors++;
-               spin_unlock(q->queue_lock);
-               nbd_end_request(req);
-               spin_lock(q->queue_lock);
        }
-       return;
 }
 
-static int nbd_ioctl(struct inode *inode, struct file *file,
-                    unsigned int cmd, unsigned long arg)
-{
-       struct nbd_device *lo = inode->i_bdev->bd_disk->private_data;
-       int error;
-       struct request sreq ;
+/* Must be called with tx_lock held */
 
-       if (!capable(CAP_SYS_ADMIN))
-               return -EPERM;
-
-       BUG_ON(lo->magic != LO_MAGIC);
+static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
+                      unsigned int cmd, unsigned long arg)
+{
+       switch (cmd) {
+       case NBD_DISCONNECT: {
+               struct request sreq;
 
-       /* Anyone capable of this syscall can do *real bad* things */
-       dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
-                       lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
+               dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
 
-       switch (cmd) {
-       case NBD_DISCONNECT:
-               printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name);
-               sreq.flags = REQ_SPECIAL;
+               blk_rq_init(NULL, &sreq);
+               sreq.cmd_type = REQ_TYPE_SPECIAL;
                nbd_cmd(&sreq) = NBD_CMD_DISC;
-               /*
-                * Set these to sane values in case server implementation
-                * fails to check the request type first and also to keep
-                * debugging output cleaner.
-                */
-               sreq.sector = 0;
-               sreq.nr_sectors = 0;
-                if (!lo->sock)
+               if (!nbd->sock)
                        return -EINVAL;
-                nbd_send_req(lo, &sreq);
+               nbd_send_req(nbd, &sreq);
                 return 0;
+       }
  
-       case NBD_CLEAR_SOCK:
-               error = 0;
-               down(&lo->tx_lock);
-               lo->sock = NULL;
-               up(&lo->tx_lock);
-               spin_lock(&lo->queue_lock);
-               file = lo->file;
-               lo->file = NULL;
-               spin_unlock(&lo->queue_lock);
-               nbd_clear_que(lo);
-               spin_lock(&lo->queue_lock);
-               if (!list_empty(&lo->queue_head)) {
-                       printk(KERN_ERR "nbd: disconnect: some requests are in progress -> please try again.\n");
-                       error = -EBUSY;
-               }
-               spin_unlock(&lo->queue_lock);
+       case NBD_CLEAR_SOCK: {
+               struct file *file;
+
+               nbd->sock = NULL;
+               file = nbd->file;
+               nbd->file = NULL;
+               nbd_clear_que(nbd);
+               BUG_ON(!list_empty(&nbd->queue_head));
                if (file)
                        fput(file);
-               return error;
-       case NBD_SET_SOCK:
-               if (lo->file)
+               return 0;
+       }
+
+       case NBD_SET_SOCK: {
+               struct file *file;
+               if (nbd->file)
                        return -EBUSY;
-               error = -EINVAL;
                file = fget(arg);
                if (file) {
-                       inode = file->f_dentry->d_inode;
+                       struct inode *inode = file->f_path.dentry->d_inode;
                        if (S_ISSOCK(inode->i_mode)) {
-                               lo->file = file;
-                               lo->sock = SOCKET_I(inode);
-                               error = 0;
+                               nbd->file = file;
+                               nbd->sock = SOCKET_I(inode);
+                               if (max_part > 0)
+                                       bdev->bd_invalidated = 1;
+                               return 0;
                        } else {
                                fput(file);
                        }
                }
-               return error;
+               return -EINVAL;
+       }
+
        case NBD_SET_BLKSIZE:
-               lo->blksize = arg;
-               lo->bytesize &= ~(lo->blksize-1);
-               inode->i_bdev->bd_inode->i_size = lo->bytesize;
-               set_blocksize(inode->i_bdev, lo->blksize);
-               set_capacity(lo->disk, lo->bytesize >> 9);
+               nbd->blksize = arg;
+               nbd->bytesize &= ~(nbd->blksize-1);
+               bdev->bd_inode->i_size = nbd->bytesize;
+               set_blocksize(bdev, nbd->blksize);
+               set_capacity(nbd->disk, nbd->bytesize >> 9);
                return 0;
+
        case NBD_SET_SIZE:
-               lo->bytesize = arg & ~(lo->blksize-1);
-               inode->i_bdev->bd_inode->i_size = lo->bytesize;
-               set_blocksize(inode->i_bdev, lo->blksize);
-               set_capacity(lo->disk, lo->bytesize >> 9);
+               nbd->bytesize = arg & ~(nbd->blksize-1);
+               bdev->bd_inode->i_size = nbd->bytesize;
+               set_blocksize(bdev, nbd->blksize);
+               set_capacity(nbd->disk, nbd->bytesize >> 9);
+               return 0;
+
+       case NBD_SET_TIMEOUT:
+               nbd->xmit_timeout = arg * HZ;
                return 0;
+
        case NBD_SET_SIZE_BLOCKS:
-               lo->bytesize = ((u64) arg) * lo->blksize;
-               inode->i_bdev->bd_inode->i_size = lo->bytesize;
-               set_blocksize(inode->i_bdev, lo->blksize);
-               set_capacity(lo->disk, lo->bytesize >> 9);
+               nbd->bytesize = ((u64) arg) * nbd->blksize;
+               bdev->bd_inode->i_size = nbd->bytesize;
+               set_blocksize(bdev, nbd->blksize);
+               set_capacity(nbd->disk, nbd->bytesize >> 9);
                return 0;
-       case NBD_DO_IT:
-               if (!lo->file)
+
+       case NBD_DO_IT: {
+               struct task_struct *thread;
+               struct file *file;
+               int error;
+
+               if (nbd->pid)
+                       return -EBUSY;
+               if (!nbd->file)
                        return -EINVAL;
-               nbd_do_it(lo);
-               /* on return tidy up in case we have a signal */
-               /* Forcibly shutdown the socket causing all listeners
-                * to error
-                *
-                * FIXME: This code is duplicated from sys_shutdown, but
-                * there should be a more generic interface rather than
-                * calling socket ops directly here */
-               down(&lo->tx_lock);
-               if (lo->sock) {
-                       printk(KERN_WARNING "%s: shutting down socket\n",
-                               lo->disk->disk_name);
-                       lo->sock->ops->shutdown(lo->sock,
-                               SEND_SHUTDOWN|RCV_SHUTDOWN);
-                       lo->sock = NULL;
+
+               mutex_unlock(&nbd->tx_lock);
+
+               thread = kthread_create(nbd_thread, nbd, nbd->disk->disk_name);
+               if (IS_ERR(thread)) {
+                       mutex_lock(&nbd->tx_lock);
+                       return PTR_ERR(thread);
                }
-               up(&lo->tx_lock);
-               spin_lock(&lo->queue_lock);
-               file = lo->file;
-               lo->file = NULL;
-               spin_unlock(&lo->queue_lock);
-               nbd_clear_que(lo);
-               printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name);
+               wake_up_process(thread);
+               error = nbd_do_it(nbd);
+               kthread_stop(thread);
+
+               mutex_lock(&nbd->tx_lock);
+               if (error)
+                       return error;
+               sock_shutdown(nbd, 0);
+               file = nbd->file;
+               nbd->file = NULL;
+               nbd_clear_que(nbd);
+               dev_warn(disk_to_dev(nbd->disk), "queue cleared\n");
                if (file)
                        fput(file);
-               return lo->harderror;
+               nbd->bytesize = 0;
+               bdev->bd_inode->i_size = 0;
+               set_capacity(nbd->disk, 0);
+               if (max_part > 0)
+                       ioctl_by_bdev(bdev, BLKRRPART, 0);
+               return nbd->harderror;
+       }
+
        case NBD_CLEAR_QUE:
-               down(&lo->tx_lock);
-               if (lo->sock) {
-                       up(&lo->tx_lock);
-                       return 0; /* probably should be error, but that would
-                                  * break "nbd-client -d", so just return 0 */
-               }
-               up(&lo->tx_lock);
-               nbd_clear_que(lo);
+               /*
+                * This is for compatibility only.  The queue is always cleared
+                * by NBD_DO_IT or NBD_CLEAR_SOCK.
+                */
+               BUG_ON(!nbd->sock && !list_empty(&nbd->queue_head));
                return 0;
+
        case NBD_PRINT_DEBUG:
-               printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n",
-                       inode->i_bdev->bd_disk->disk_name,
-                       lo->queue_head.next, lo->queue_head.prev,
-                       &lo->queue_head);
+               dev_info(disk_to_dev(nbd->disk),
+                       "next = %p, prev = %p, head = %p\n",
+                       nbd->queue_head.next, nbd->queue_head.prev,
+                       &nbd->queue_head);
                return 0;
        }
-       return -EINVAL;
+       return -ENOTTY;
+}
+
+static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
+                    unsigned int cmd, unsigned long arg)
+{
+       struct nbd_device *nbd = bdev->bd_disk->private_data;
+       int error;
+
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
+
+       BUG_ON(nbd->magic != NBD_MAGIC);
+
+       /* Anyone capable of this syscall can do *real bad* things */
+       dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
+               nbd->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
+
+       mutex_lock(&nbd->tx_lock);
+       error = __nbd_ioctl(bdev, nbd, cmd, arg);
+       mutex_unlock(&nbd->tx_lock);
+
+       return error;
 }
 
-static struct block_device_operations nbd_fops =
+static const struct block_device_operations nbd_fops =
 {
        .owner =        THIS_MODULE,
        .ioctl =        nbd_ioctl,
@@ -642,20 +740,42 @@ static int __init nbd_init(void)
 {
        int err = -ENOMEM;
        int i;
+       int part_shift;
 
-       if (sizeof(struct nbd_request) != 28) {
-               printk(KERN_CRIT "nbd: sizeof nbd_request needs to be 28 in order to work!\n" );
-               return -EIO;
-       }
+       BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
 
-       if (nbds_max > MAX_NBD) {
-               printk(KERN_CRIT "nbd: cannot allocate more than %u nbds; %u requested.\n", MAX_NBD,
-                               nbds_max);
+       if (max_part < 0) {
+               printk(KERN_ERR "nbd: max_part must be >= 0\n");
                return -EINVAL;
        }
 
+       nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
+       if (!nbd_dev)
+               return -ENOMEM;
+
+       part_shift = 0;
+       if (max_part > 0) {
+               part_shift = fls(max_part);
+
+               /*
+                * Adjust max_part according to part_shift as it is exported
+                * to user space so that user can know the max number of
+                * partition kernel should be able to manage.
+                *
+                * Note that -1 is required because partition 0 is reserved
+                * for the whole disk.
+                */
+               max_part = (1UL << part_shift) - 1;
+       }
+
+       if ((1UL << part_shift) > DISK_MAX_PARTS)
+               return -EINVAL;
+
+       if (nbds_max > 1UL << (MINORBITS - part_shift))
+               return -EINVAL;
+
        for (i = 0; i < nbds_max; i++) {
-               struct gendisk *disk = alloc_disk(1);
+               struct gendisk *disk = alloc_disk(1 << part_shift);
                if (!disk)
                        goto out;
                nbd_dev[i].disk = disk;
@@ -669,6 +789,10 @@ static int __init nbd_init(void)
                        put_disk(disk);
                        goto out;
                }
+               /*
+                * Tell the block layer that we are not a rotational device
+                */
+               queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
        }
 
        if (register_blkdev(NBD_MAJOR, "nbd")) {
@@ -679,25 +803,25 @@ static int __init nbd_init(void)
        printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
        dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
 
-       devfs_mk_dir("nbd");
        for (i = 0; i < nbds_max; i++) {
                struct gendisk *disk = nbd_dev[i].disk;
                nbd_dev[i].file = NULL;
-               nbd_dev[i].magic = LO_MAGIC;
+               nbd_dev[i].magic = NBD_MAGIC;
                nbd_dev[i].flags = 0;
+               INIT_LIST_HEAD(&nbd_dev[i].waiting_queue);
                spin_lock_init(&nbd_dev[i].queue_lock);
                INIT_LIST_HEAD(&nbd_dev[i].queue_head);
-               init_MUTEX(&nbd_dev[i].tx_lock);
+               mutex_init(&nbd_dev[i].tx_lock);
+               init_waitqueue_head(&nbd_dev[i].active_wq);
+               init_waitqueue_head(&nbd_dev[i].waiting_wq);
                nbd_dev[i].blksize = 1024;
-               nbd_dev[i].bytesize = 0x7ffffc00ULL << 10; /* 2TB */
+               nbd_dev[i].bytesize = 0;
                disk->major = NBD_MAJOR;
-               disk->first_minor = i;
+               disk->first_minor = i << part_shift;
                disk->fops = &nbd_fops;
                disk->private_data = &nbd_dev[i];
-               disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
                sprintf(disk->disk_name, "nbd%d", i);
-               sprintf(disk->devfs_name, "nbd/%d", i);
-               set_capacity(disk, 0x7ffffc00ULL << 1); /* 2 TB */
+               set_capacity(disk, 0);
                add_disk(disk);
        }
 
@@ -707,6 +831,7 @@ out:
                blk_cleanup_queue(nbd_dev[i].disk->queue);
                put_disk(nbd_dev[i].disk);
        }
+       kfree(nbd_dev);
        return err;
 }
 
@@ -722,8 +847,8 @@ static void __exit nbd_cleanup(void)
                        put_disk(disk);
                }
        }
-       devfs_remove("nbd");
        unregister_blkdev(NBD_MAJOR, "nbd");
+       kfree(nbd_dev);
        printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
 }
 
@@ -734,7 +859,9 @@ MODULE_DESCRIPTION("Network Block Device");
 MODULE_LICENSE("GPL");
 
 module_param(nbds_max, int, 0444);
-MODULE_PARM_DESC(nbds_max, "How many network block devices to initialize.");
+MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
+module_param(max_part, int, 0444);
+MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");
 #ifndef NDEBUG
 module_param(debugflags, int, 0644);
 MODULE_PARM_DESC(debugflags, "flags for controlling debug output");