* Copyright 1997-2000 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/compiler.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
#include <net/sock.h>
-#include <linux/devfs_fs_kernel.h>
-
#include <asm/uaccess.h>
+#include <asm/system.h>
#include <asm/types.h>
#include <linux/nbd.h>
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)
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,
nbdcmd_to_ascii(nbd_cmd(req)),
}
}
}
- up(&lo->tx_lock);
return 0;
error_out:
- up(&lo->tx_lock);
return 1;
}
struct request *req;
struct list_head *tmp;
struct request *xreq;
+ int err;
memcpy(&xreq, handle, sizeof(xreq));
+ err = wait_event_interruptible(lo->active_wq, lo->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);
return req;
}
spin_unlock(&lo->queue_lock);
- return NULL;
+
+ err = -ENOENT;
+
+out:
+ return ERR_PTR(err);
}
static inline int sock_recv_bvec(struct socket *sock, struct bio_vec *bvec)
goto harderror;
}
req = nbd_find_request(lo, reply.handle);
- if (req == NULL) {
+ if (unlikely(IS_ERR(req))) {
+ result = PTR_ERR(req);
+ if (result != -ENOENT)
+ goto harderror;
+
printk(KERN_ERR "%s: Unexpected reply (%p)\n",
lo->disk->disk_name, reply.handle);
result = -EBADR;
BUG_ON(lo->magic != LO_MAGIC);
- 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);
- }
- } while (req);
+ /*
+ * Because we have set lo->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(lo->sock);
+ BUG_ON(lo->active_req);
+
+ while (!list_empty(&lo->queue_head)) {
+ req = list_entry(lo->queue_head.next, struct request,
+ queuelist);
+ list_del_init(&req->queuelist);
+ req->errors++;
+ nbd_end_request(req);
+ }
}
/*
BUG_ON(lo->magic != LO_MAGIC);
- 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;
req->errors = 0;
spin_unlock_irq(q->queue_lock);
- spin_lock(&lo->queue_lock);
-
- if (!lo->file) {
- spin_unlock(&lo->queue_lock);
- printk(KERN_ERR "%s: failed between accept and semaphore, file lost\n",
- lo->disk->disk_name);
+ mutex_lock(&lo->tx_lock);
+ if (unlikely(!lo->sock)) {
+ mutex_unlock(&lo->tx_lock);
+ printk(KERN_ERR "%s: Attempted send on closed socket\n",
+ lo->disk->disk_name);
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);
+ lo->active_req = req;
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");
+ req->errors++;
+ nbd_end_request(req);
+ } else {
+ spin_lock(&lo->queue_lock);
+ list_add(&req->queuelist, &lo->queue_head);
+ spin_unlock(&lo->queue_lock);
}
+ lo->active_req = NULL;
+ mutex_unlock(&lo->tx_lock);
+ wake_up_all(&lo->active_wq);
+
spin_lock_irq(q->queue_lock);
continue;
case NBD_CLEAR_SOCK:
error = 0;
- down(&lo->tx_lock);
+ mutex_lock(&lo->tx_lock);
lo->sock = NULL;
- up(&lo->tx_lock);
- spin_lock(&lo->queue_lock);
+ mutex_unlock(&lo->tx_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);
+ BUG_ON(!list_empty(&lo->queue_head));
if (file)
fput(file);
return 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);
+ mutex_lock(&lo->tx_lock);
if (lo->sock) {
printk(KERN_WARNING "%s: shutting down socket\n",
lo->disk->disk_name);
SEND_SHUTDOWN|RCV_SHUTDOWN);
lo->sock = NULL;
}
- up(&lo->tx_lock);
- spin_lock(&lo->queue_lock);
+ mutex_unlock(&lo->tx_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);
if (file)
fput(file);
return lo->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(!lo->sock && !list_empty(&lo->queue_head));
return 0;
case NBD_PRINT_DEBUG:
printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n",
int err = -ENOMEM;
int i;
- 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,
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].flags = 0;
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);
nbd_dev[i].blksize = 1024;
nbd_dev[i].bytesize = 0x7ffffc00ULL << 10; /* 2TB */
disk->major = NBD_MAJOR;
put_disk(disk);
}
}
- devfs_remove("nbd");
unregister_blkdev(NBD_MAJOR, "nbd");
printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff