| /* |
| * blkfront.c |
| * |
| * XenLinux virtual block device driver. |
| * |
| * Copyright (c) 2003-2004, Keir Fraser & Steve Hand |
| * Modifications by Mark A. Williamson are (c) Intel Research Cambridge |
| * Copyright (c) 2004, Christian Limpach |
| * Copyright (c) 2004, Andrew Warfield |
| * Copyright (c) 2005, Christopher Clark |
| * Copyright (c) 2005, XenSource Ltd |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License version 2 |
| * as published by the Free Software Foundation; or, when distributed |
| * separately from the Linux kernel or incorporated into other |
| * software packages, subject to the following license: |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this source file (the "Software"), to deal in the Software without |
| * restriction, including without limitation the rights to use, copy, modify, |
| * merge, publish, distribute, sublicense, and/or sell copies of the Software, |
| * and to permit persons to whom the Software is furnished to do so, subject to |
| * the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| * IN THE SOFTWARE. |
| */ |
| |
| #include <linux/interrupt.h> |
| #include <linux/blkdev.h> |
| #include <linux/hdreg.h> |
| #include <linux/cdrom.h> |
| #include <linux/module.h> |
| #include <linux/scatterlist.h> |
| |
| #include <xen/xenbus.h> |
| #include <xen/grant_table.h> |
| #include <xen/events.h> |
| #include <xen/page.h> |
| |
| #include <xen/interface/grant_table.h> |
| #include <xen/interface/io/blkif.h> |
| #include <xen/interface/io/protocols.h> |
| |
| #include <asm/xen/hypervisor.h> |
| |
| enum blkif_state { |
| BLKIF_STATE_DISCONNECTED, |
| BLKIF_STATE_CONNECTED, |
| BLKIF_STATE_SUSPENDED, |
| }; |
| |
| struct blk_shadow { |
| struct blkif_request req; |
| unsigned long request; |
| unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
| }; |
| |
| static struct block_device_operations xlvbd_block_fops; |
| |
| #define BLK_RING_SIZE __RING_SIZE((struct blkif_sring *)0, PAGE_SIZE) |
| |
| /* |
| * We have one of these per vbd, whether ide, scsi or 'other'. They |
| * hang in private_data off the gendisk structure. We may end up |
| * putting all kinds of interesting stuff here :-) |
| */ |
| struct blkfront_info |
| { |
| struct xenbus_device *xbdev; |
| struct gendisk *gd; |
| int vdevice; |
| blkif_vdev_t handle; |
| enum blkif_state connected; |
| int ring_ref; |
| struct blkif_front_ring ring; |
| struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
| unsigned int evtchn, irq; |
| struct request_queue *rq; |
| struct work_struct work; |
| struct gnttab_free_callback callback; |
| struct blk_shadow shadow[BLK_RING_SIZE]; |
| unsigned long shadow_free; |
| int feature_barrier; |
| int is_ready; |
| |
| /** |
| * The number of people holding this device open. We won't allow a |
| * hot-unplug unless this is 0. |
| */ |
| int users; |
| }; |
| |
| static DEFINE_SPINLOCK(blkif_io_lock); |
| |
| #define MAXIMUM_OUTSTANDING_BLOCK_REQS \ |
| (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE) |
| #define GRANT_INVALID_REF 0 |
| |
| #define PARTS_PER_DISK 16 |
| #define PARTS_PER_EXT_DISK 256 |
| |
| #define BLKIF_MAJOR(dev) ((dev)>>8) |
| #define BLKIF_MINOR(dev) ((dev) & 0xff) |
| |
| #define EXT_SHIFT 28 |
| #define EXTENDED (1<<EXT_SHIFT) |
| #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED)) |
| #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED)) |
| |
| #define DEV_NAME "xvd" /* name in /dev */ |
| |
| static int get_id_from_freelist(struct blkfront_info *info) |
| { |
| unsigned long free = info->shadow_free; |
| BUG_ON(free > BLK_RING_SIZE); |
| info->shadow_free = info->shadow[free].req.id; |
| info->shadow[free].req.id = 0x0fffffee; /* debug */ |
| return free; |
| } |
| |
| static void add_id_to_freelist(struct blkfront_info *info, |
| unsigned long id) |
| { |
| info->shadow[id].req.id = info->shadow_free; |
| info->shadow[id].request = 0; |
| info->shadow_free = id; |
| } |
| |
| static void blkif_restart_queue_callback(void *arg) |
| { |
| struct blkfront_info *info = (struct blkfront_info *)arg; |
| schedule_work(&info->work); |
| } |
| |
| static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg) |
| { |
| /* We don't have real geometry info, but let's at least return |
| values consistent with the size of the device */ |
| sector_t nsect = get_capacity(bd->bd_disk); |
| sector_t cylinders = nsect; |
| |
| hg->heads = 0xff; |
| hg->sectors = 0x3f; |
| sector_div(cylinders, hg->heads * hg->sectors); |
| hg->cylinders = cylinders; |
| if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect) |
| hg->cylinders = 0xffff; |
| return 0; |
| } |
| |
| static int blkif_ioctl(struct block_device *bdev, fmode_t mode, |
| unsigned command, unsigned long argument) |
| { |
| struct blkfront_info *info = bdev->bd_disk->private_data; |
| int i; |
| |
| dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n", |
| command, (long)argument); |
| |
| switch (command) { |
| case CDROMMULTISESSION: |
| dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n"); |
| for (i = 0; i < sizeof(struct cdrom_multisession); i++) |
| if (put_user(0, (char __user *)(argument + i))) |
| return -EFAULT; |
| return 0; |
| |
| case CDROM_GET_CAPABILITY: { |
| struct gendisk *gd = info->gd; |
| if (gd->flags & GENHD_FL_CD) |
| return 0; |
| return -EINVAL; |
| } |
| |
| default: |
| /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n", |
| command);*/ |
| return -EINVAL; /* same return as native Linux */ |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * blkif_queue_request |
| * |
| * request block io |
| * |
| * id: for guest use only. |
| * operation: BLKIF_OP_{READ,WRITE,PROBE} |
| * buffer: buffer to read/write into. this should be a |
| * virtual address in the guest os. |
| */ |
| static int blkif_queue_request(struct request *req) |
| { |
| struct blkfront_info *info = req->rq_disk->private_data; |
| unsigned long buffer_mfn; |
| struct blkif_request *ring_req; |
| unsigned long id; |
| unsigned int fsect, lsect; |
| int i, ref; |
| grant_ref_t gref_head; |
| struct scatterlist *sg; |
| |
| if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) |
| return 1; |
| |
| if (gnttab_alloc_grant_references( |
| BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) { |
| gnttab_request_free_callback( |
| &info->callback, |
| blkif_restart_queue_callback, |
| info, |
| BLKIF_MAX_SEGMENTS_PER_REQUEST); |
| return 1; |
| } |
| |
| /* Fill out a communications ring structure. */ |
| ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt); |
| id = get_id_from_freelist(info); |
| info->shadow[id].request = (unsigned long)req; |
| |
| ring_req->id = id; |
| ring_req->sector_number = (blkif_sector_t)blk_rq_pos(req); |
| ring_req->handle = info->handle; |
| |
| ring_req->operation = rq_data_dir(req) ? |
| BLKIF_OP_WRITE : BLKIF_OP_READ; |
| if (blk_barrier_rq(req)) |
| ring_req->operation = BLKIF_OP_WRITE_BARRIER; |
| |
| ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg); |
| BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST); |
| |
| for_each_sg(info->sg, sg, ring_req->nr_segments, i) { |
| buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg))); |
| fsect = sg->offset >> 9; |
| lsect = fsect + (sg->length >> 9) - 1; |
| /* install a grant reference. */ |
| ref = gnttab_claim_grant_reference(&gref_head); |
| BUG_ON(ref == -ENOSPC); |
| |
| gnttab_grant_foreign_access_ref( |
| ref, |
| info->xbdev->otherend_id, |
| buffer_mfn, |
| rq_data_dir(req) ); |
| |
| info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn); |
| ring_req->seg[i] = |
| (struct blkif_request_segment) { |
| .gref = ref, |
| .first_sect = fsect, |
| .last_sect = lsect }; |
| } |
| |
| info->ring.req_prod_pvt++; |
| |
| /* Keep a private copy so we can reissue requests when recovering. */ |
| info->shadow[id].req = *ring_req; |
| |
| gnttab_free_grant_references(gref_head); |
| |
| return 0; |
| } |
| |
| |
| static inline void flush_requests(struct blkfront_info *info) |
| { |
| int notify; |
| |
| RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify); |
| |
| if (notify) |
| notify_remote_via_irq(info->irq); |
| } |
| |
| /* |
| * do_blkif_request |
| * read a block; request is in a request queue |
| */ |
| static void do_blkif_request(struct request_queue *rq) |
| { |
| struct blkfront_info *info = NULL; |
| struct request *req; |
| int queued; |
| |
| pr_debug("Entered do_blkif_request\n"); |
| |
| queued = 0; |
| |
| while ((req = elv_next_request(rq)) != NULL) { |
| info = req->rq_disk->private_data; |
| if (!blk_fs_request(req)) { |
| __blk_end_request_cur(req, -EIO); |
| continue; |
| } |
| |
| if (RING_FULL(&info->ring)) |
| goto wait; |
| |
| pr_debug("do_blk_req %p: cmd %p, sec %lx, " |
| "(%u/%u) buffer:%p [%s]\n", |
| req, req->cmd, (unsigned long)blk_rq_pos(req), |
| blk_rq_cur_sectors(req), blk_rq_sectors(req), |
| req->buffer, rq_data_dir(req) ? "write" : "read"); |
| |
| |
| blkdev_dequeue_request(req); |
| if (blkif_queue_request(req)) { |
| blk_requeue_request(rq, req); |
| wait: |
| /* Avoid pointless unplugs. */ |
| blk_stop_queue(rq); |
| break; |
| } |
| |
| queued++; |
| } |
| |
| if (queued != 0) |
| flush_requests(info); |
| } |
| |
| static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size) |
| { |
| struct request_queue *rq; |
| |
| rq = blk_init_queue(do_blkif_request, &blkif_io_lock); |
| if (rq == NULL) |
| return -1; |
| |
| queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq); |
| |
| /* Hard sector size and max sectors impersonate the equiv. hardware. */ |
| blk_queue_hardsect_size(rq, sector_size); |
| blk_queue_max_sectors(rq, 512); |
| |
| /* Each segment in a request is up to an aligned page in size. */ |
| blk_queue_segment_boundary(rq, PAGE_SIZE - 1); |
| blk_queue_max_segment_size(rq, PAGE_SIZE); |
| |
| /* Ensure a merged request will fit in a single I/O ring slot. */ |
| blk_queue_max_phys_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST); |
| blk_queue_max_hw_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST); |
| |
| /* Make sure buffer addresses are sector-aligned. */ |
| blk_queue_dma_alignment(rq, 511); |
| |
| /* Make sure we don't use bounce buffers. */ |
| blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY); |
| |
| gd->queue = rq; |
| |
| return 0; |
| } |
| |
| |
| static int xlvbd_barrier(struct blkfront_info *info) |
| { |
| int err; |
| |
| err = blk_queue_ordered(info->rq, |
| info->feature_barrier ? QUEUE_ORDERED_DRAIN : QUEUE_ORDERED_NONE, |
| NULL); |
| |
| if (err) |
| return err; |
| |
| printk(KERN_INFO "blkfront: %s: barriers %s\n", |
| info->gd->disk_name, |
| info->feature_barrier ? "enabled" : "disabled"); |
| return 0; |
| } |
| |
| |
| static int xlvbd_alloc_gendisk(blkif_sector_t capacity, |
| struct blkfront_info *info, |
| u16 vdisk_info, u16 sector_size) |
| { |
| struct gendisk *gd; |
| int nr_minors = 1; |
| int err = -ENODEV; |
| unsigned int offset; |
| int minor; |
| int nr_parts; |
| |
| BUG_ON(info->gd != NULL); |
| BUG_ON(info->rq != NULL); |
| |
| if ((info->vdevice>>EXT_SHIFT) > 1) { |
| /* this is above the extended range; something is wrong */ |
| printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice); |
| return -ENODEV; |
| } |
| |
| if (!VDEV_IS_EXTENDED(info->vdevice)) { |
| minor = BLKIF_MINOR(info->vdevice); |
| nr_parts = PARTS_PER_DISK; |
| } else { |
| minor = BLKIF_MINOR_EXT(info->vdevice); |
| nr_parts = PARTS_PER_EXT_DISK; |
| } |
| |
| if ((minor % nr_parts) == 0) |
| nr_minors = nr_parts; |
| |
| gd = alloc_disk(nr_minors); |
| if (gd == NULL) |
| goto out; |
| |
| offset = minor / nr_parts; |
| |
| if (nr_minors > 1) { |
| if (offset < 26) |
| sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset); |
| else |
| sprintf(gd->disk_name, "%s%c%c", DEV_NAME, |
| 'a' + ((offset / 26)-1), 'a' + (offset % 26)); |
| } else { |
| if (offset < 26) |
| sprintf(gd->disk_name, "%s%c%d", DEV_NAME, |
| 'a' + offset, |
| minor & (nr_parts - 1)); |
| else |
| sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME, |
| 'a' + ((offset / 26) - 1), |
| 'a' + (offset % 26), |
| minor & (nr_parts - 1)); |
| } |
| |
| gd->major = XENVBD_MAJOR; |
| gd->first_minor = minor; |
| gd->fops = &xlvbd_block_fops; |
| gd->private_data = info; |
| gd->driverfs_dev = &(info->xbdev->dev); |
| set_capacity(gd, capacity); |
| |
| if (xlvbd_init_blk_queue(gd, sector_size)) { |
| del_gendisk(gd); |
| goto out; |
| } |
| |
| info->rq = gd->queue; |
| info->gd = gd; |
| |
| if (info->feature_barrier) |
| xlvbd_barrier(info); |
| |
| if (vdisk_info & VDISK_READONLY) |
| set_disk_ro(gd, 1); |
| |
| if (vdisk_info & VDISK_REMOVABLE) |
| gd->flags |= GENHD_FL_REMOVABLE; |
| |
| if (vdisk_info & VDISK_CDROM) |
| gd->flags |= GENHD_FL_CD; |
| |
| return 0; |
| |
| out: |
| return err; |
| } |
| |
| static void kick_pending_request_queues(struct blkfront_info *info) |
| { |
| if (!RING_FULL(&info->ring)) { |
| /* Re-enable calldowns. */ |
| blk_start_queue(info->rq); |
| /* Kick things off immediately. */ |
| do_blkif_request(info->rq); |
| } |
| } |
| |
| static void blkif_restart_queue(struct work_struct *work) |
| { |
| struct blkfront_info *info = container_of(work, struct blkfront_info, work); |
| |
| spin_lock_irq(&blkif_io_lock); |
| if (info->connected == BLKIF_STATE_CONNECTED) |
| kick_pending_request_queues(info); |
| spin_unlock_irq(&blkif_io_lock); |
| } |
| |
| static void blkif_free(struct blkfront_info *info, int suspend) |
| { |
| /* Prevent new requests being issued until we fix things up. */ |
| spin_lock_irq(&blkif_io_lock); |
| info->connected = suspend ? |
| BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; |
| /* No more blkif_request(). */ |
| if (info->rq) |
| blk_stop_queue(info->rq); |
| /* No more gnttab callback work. */ |
| gnttab_cancel_free_callback(&info->callback); |
| spin_unlock_irq(&blkif_io_lock); |
| |
| /* Flush gnttab callback work. Must be done with no locks held. */ |
| flush_scheduled_work(); |
| |
| /* Free resources associated with old device channel. */ |
| if (info->ring_ref != GRANT_INVALID_REF) { |
| gnttab_end_foreign_access(info->ring_ref, 0, |
| (unsigned long)info->ring.sring); |
| info->ring_ref = GRANT_INVALID_REF; |
| info->ring.sring = NULL; |
| } |
| if (info->irq) |
| unbind_from_irqhandler(info->irq, info); |
| info->evtchn = info->irq = 0; |
| |
| } |
| |
| static void blkif_completion(struct blk_shadow *s) |
| { |
| int i; |
| for (i = 0; i < s->req.nr_segments; i++) |
| gnttab_end_foreign_access(s->req.seg[i].gref, 0, 0UL); |
| } |
| |
| static irqreturn_t blkif_interrupt(int irq, void *dev_id) |
| { |
| struct request *req; |
| struct blkif_response *bret; |
| RING_IDX i, rp; |
| unsigned long flags; |
| struct blkfront_info *info = (struct blkfront_info *)dev_id; |
| int error; |
| |
| spin_lock_irqsave(&blkif_io_lock, flags); |
| |
| if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) { |
| spin_unlock_irqrestore(&blkif_io_lock, flags); |
| return IRQ_HANDLED; |
| } |
| |
| again: |
| rp = info->ring.sring->rsp_prod; |
| rmb(); /* Ensure we see queued responses up to 'rp'. */ |
| |
| for (i = info->ring.rsp_cons; i != rp; i++) { |
| unsigned long id; |
| |
| bret = RING_GET_RESPONSE(&info->ring, i); |
| id = bret->id; |
| req = (struct request *)info->shadow[id].request; |
| |
| blkif_completion(&info->shadow[id]); |
| |
| add_id_to_freelist(info, id); |
| |
| error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO; |
| switch (bret->operation) { |
| case BLKIF_OP_WRITE_BARRIER: |
| if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { |
| printk(KERN_WARNING "blkfront: %s: write barrier op failed\n", |
| info->gd->disk_name); |
| error = -EOPNOTSUPP; |
| info->feature_barrier = 0; |
| xlvbd_barrier(info); |
| } |
| /* fall through */ |
| case BLKIF_OP_READ: |
| case BLKIF_OP_WRITE: |
| if (unlikely(bret->status != BLKIF_RSP_OKAY)) |
| dev_dbg(&info->xbdev->dev, "Bad return from blkdev data " |
| "request: %x\n", bret->status); |
| |
| __blk_end_request_all(req, error); |
| break; |
| default: |
| BUG(); |
| } |
| } |
| |
| info->ring.rsp_cons = i; |
| |
| if (i != info->ring.req_prod_pvt) { |
| int more_to_do; |
| RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do); |
| if (more_to_do) |
| goto again; |
| } else |
| info->ring.sring->rsp_event = i + 1; |
| |
| kick_pending_request_queues(info); |
| |
| spin_unlock_irqrestore(&blkif_io_lock, flags); |
| |
| return IRQ_HANDLED; |
| } |
| |
| |
| static int setup_blkring(struct xenbus_device *dev, |
| struct blkfront_info *info) |
| { |
| struct blkif_sring *sring; |
| int err; |
| |
| info->ring_ref = GRANT_INVALID_REF; |
| |
| sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH); |
| if (!sring) { |
| xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); |
| return -ENOMEM; |
| } |
| SHARED_RING_INIT(sring); |
| FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE); |
| |
| sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST); |
| |
| err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring)); |
| if (err < 0) { |
| free_page((unsigned long)sring); |
| info->ring.sring = NULL; |
| goto fail; |
| } |
| info->ring_ref = err; |
| |
| err = xenbus_alloc_evtchn(dev, &info->evtchn); |
| if (err) |
| goto fail; |
| |
| err = bind_evtchn_to_irqhandler(info->evtchn, |
| blkif_interrupt, |
| IRQF_SAMPLE_RANDOM, "blkif", info); |
| if (err <= 0) { |
| xenbus_dev_fatal(dev, err, |
| "bind_evtchn_to_irqhandler failed"); |
| goto fail; |
| } |
| info->irq = err; |
| |
| return 0; |
| fail: |
| blkif_free(info, 0); |
| return err; |
| } |
| |
| |
| /* Common code used when first setting up, and when resuming. */ |
| static int talk_to_backend(struct xenbus_device *dev, |
| struct blkfront_info *info) |
| { |
| const char *message = NULL; |
| struct xenbus_transaction xbt; |
| int err; |
| |
| /* Create shared ring, alloc event channel. */ |
| err = setup_blkring(dev, info); |
| if (err) |
| goto out; |
| |
| again: |
| err = xenbus_transaction_start(&xbt); |
| if (err) { |
| xenbus_dev_fatal(dev, err, "starting transaction"); |
| goto destroy_blkring; |
| } |
| |
| err = xenbus_printf(xbt, dev->nodename, |
| "ring-ref", "%u", info->ring_ref); |
| if (err) { |
| message = "writing ring-ref"; |
| goto abort_transaction; |
| } |
| err = xenbus_printf(xbt, dev->nodename, |
| "event-channel", "%u", info->evtchn); |
| if (err) { |
| message = "writing event-channel"; |
| goto abort_transaction; |
| } |
| err = xenbus_printf(xbt, dev->nodename, "protocol", "%s", |
| XEN_IO_PROTO_ABI_NATIVE); |
| if (err) { |
| message = "writing protocol"; |
| goto abort_transaction; |
| } |
| |
| err = xenbus_transaction_end(xbt, 0); |
| if (err) { |
| if (err == -EAGAIN) |
| goto again; |
| xenbus_dev_fatal(dev, err, "completing transaction"); |
| goto destroy_blkring; |
| } |
| |
| xenbus_switch_state(dev, XenbusStateInitialised); |
| |
| return 0; |
| |
| abort_transaction: |
| xenbus_transaction_end(xbt, 1); |
| if (message) |
| xenbus_dev_fatal(dev, err, "%s", message); |
| destroy_blkring: |
| blkif_free(info, 0); |
| out: |
| return err; |
| } |
| |
| |
| /** |
| * Entry point to this code when a new device is created. Allocate the basic |
| * structures and the ring buffer for communication with the backend, and |
| * inform the backend of the appropriate details for those. Switch to |
| * Initialised state. |
| */ |
| static int blkfront_probe(struct xenbus_device *dev, |
| const struct xenbus_device_id *id) |
| { |
| int err, vdevice, i; |
| struct blkfront_info *info; |
| |
| /* FIXME: Use dynamic device id if this is not set. */ |
| err = xenbus_scanf(XBT_NIL, dev->nodename, |
| "virtual-device", "%i", &vdevice); |
| if (err != 1) { |
| /* go looking in the extended area instead */ |
| err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext", |
| "%i", &vdevice); |
| if (err != 1) { |
| xenbus_dev_fatal(dev, err, "reading virtual-device"); |
| return err; |
| } |
| } |
| |
| info = kzalloc(sizeof(*info), GFP_KERNEL); |
| if (!info) { |
| xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure"); |
| return -ENOMEM; |
| } |
| |
| info->xbdev = dev; |
| info->vdevice = vdevice; |
| info->connected = BLKIF_STATE_DISCONNECTED; |
| INIT_WORK(&info->work, blkif_restart_queue); |
| |
| for (i = 0; i < BLK_RING_SIZE; i++) |
| info->shadow[i].req.id = i+1; |
| info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff; |
| |
| /* Front end dir is a number, which is used as the id. */ |
| info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0); |
| dev->dev.driver_data = info; |
| |
| err = talk_to_backend(dev, info); |
| if (err) { |
| kfree(info); |
| dev->dev.driver_data = NULL; |
| return err; |
| } |
| |
| return 0; |
| } |
| |
| |
| static int blkif_recover(struct blkfront_info *info) |
| { |
| int i; |
| struct blkif_request *req; |
| struct blk_shadow *copy; |
| int j; |
| |
| /* Stage 1: Make a safe copy of the shadow state. */ |
| copy = kmalloc(sizeof(info->shadow), |
| GFP_NOIO | __GFP_REPEAT | __GFP_HIGH); |
| if (!copy) |
| return -ENOMEM; |
| memcpy(copy, info->shadow, sizeof(info->shadow)); |
| |
| /* Stage 2: Set up free list. */ |
| memset(&info->shadow, 0, sizeof(info->shadow)); |
| for (i = 0; i < BLK_RING_SIZE; i++) |
| info->shadow[i].req.id = i+1; |
| info->shadow_free = info->ring.req_prod_pvt; |
| info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff; |
| |
| /* Stage 3: Find pending requests and requeue them. */ |
| for (i = 0; i < BLK_RING_SIZE; i++) { |
| /* Not in use? */ |
| if (copy[i].request == 0) |
| continue; |
| |
| /* Grab a request slot and copy shadow state into it. */ |
| req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt); |
| *req = copy[i].req; |
| |
| /* We get a new request id, and must reset the shadow state. */ |
| req->id = get_id_from_freelist(info); |
| memcpy(&info->shadow[req->id], ©[i], sizeof(copy[i])); |
| |
| /* Rewrite any grant references invalidated by susp/resume. */ |
| for (j = 0; j < req->nr_segments; j++) |
| gnttab_grant_foreign_access_ref( |
| req->seg[j].gref, |
| info->xbdev->otherend_id, |
| pfn_to_mfn(info->shadow[req->id].frame[j]), |
| rq_data_dir( |
| (struct request *) |
| info->shadow[req->id].request)); |
| info->shadow[req->id].req = *req; |
| |
| info->ring.req_prod_pvt++; |
| } |
| |
| kfree(copy); |
| |
| xenbus_switch_state(info->xbdev, XenbusStateConnected); |
| |
| spin_lock_irq(&blkif_io_lock); |
| |
| /* Now safe for us to use the shared ring */ |
| info->connected = BLKIF_STATE_CONNECTED; |
| |
| /* Send off requeued requests */ |
| flush_requests(info); |
| |
| /* Kick any other new requests queued since we resumed */ |
| kick_pending_request_queues(info); |
| |
| spin_unlock_irq(&blkif_io_lock); |
| |
| return 0; |
| } |
| |
| /** |
| * We are reconnecting to the backend, due to a suspend/resume, or a backend |
| * driver restart. We tear down our blkif structure and recreate it, but |
| * leave the device-layer structures intact so that this is transparent to the |
| * rest of the kernel. |
| */ |
| static int blkfront_resume(struct xenbus_device *dev) |
| { |
| struct blkfront_info *info = dev->dev.driver_data; |
| int err; |
| |
| dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename); |
| |
| blkif_free(info, info->connected == BLKIF_STATE_CONNECTED); |
| |
| err = talk_to_backend(dev, info); |
| if (info->connected == BLKIF_STATE_SUSPENDED && !err) |
| err = blkif_recover(info); |
| |
| return err; |
| } |
| |
| |
| /* |
| * Invoked when the backend is finally 'ready' (and has told produced |
| * the details about the physical device - #sectors, size, etc). |
| */ |
| static void blkfront_connect(struct blkfront_info *info) |
| { |
| unsigned long long sectors; |
| unsigned long sector_size; |
| unsigned int binfo; |
| int err; |
| |
| if ((info->connected == BLKIF_STATE_CONNECTED) || |
| (info->connected == BLKIF_STATE_SUSPENDED) ) |
| return; |
| |
| dev_dbg(&info->xbdev->dev, "%s:%s.\n", |
| __func__, info->xbdev->otherend); |
| |
| err = xenbus_gather(XBT_NIL, info->xbdev->otherend, |
| "sectors", "%llu", §ors, |
| "info", "%u", &binfo, |
| "sector-size", "%lu", §or_size, |
| NULL); |
| if (err) { |
| xenbus_dev_fatal(info->xbdev, err, |
| "reading backend fields at %s", |
| info->xbdev->otherend); |
| return; |
| } |
| |
| err = xenbus_gather(XBT_NIL, info->xbdev->otherend, |
| "feature-barrier", "%lu", &info->feature_barrier, |
| NULL); |
| if (err) |
| info->feature_barrier = 0; |
| |
| err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size); |
| if (err) { |
| xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s", |
| info->xbdev->otherend); |
| return; |
| } |
| |
| xenbus_switch_state(info->xbdev, XenbusStateConnected); |
| |
| /* Kick pending requests. */ |
| spin_lock_irq(&blkif_io_lock); |
| info->connected = BLKIF_STATE_CONNECTED; |
| kick_pending_request_queues(info); |
| spin_unlock_irq(&blkif_io_lock); |
| |
| add_disk(info->gd); |
| |
| info->is_ready = 1; |
| } |
| |
| /** |
| * Handle the change of state of the backend to Closing. We must delete our |
| * device-layer structures now, to ensure that writes are flushed through to |
| * the backend. Once is this done, we can switch to Closed in |
| * acknowledgement. |
| */ |
| static void blkfront_closing(struct xenbus_device *dev) |
| { |
| struct blkfront_info *info = dev->dev.driver_data; |
| unsigned long flags; |
| |
| dev_dbg(&dev->dev, "blkfront_closing: %s removed\n", dev->nodename); |
| |
| if (info->rq == NULL) |
| goto out; |
| |
| spin_lock_irqsave(&blkif_io_lock, flags); |
| |
| del_gendisk(info->gd); |
| |
| /* No more blkif_request(). */ |
| blk_stop_queue(info->rq); |
| |
| /* No more gnttab callback work. */ |
| gnttab_cancel_free_callback(&info->callback); |
| spin_unlock_irqrestore(&blkif_io_lock, flags); |
| |
| /* Flush gnttab callback work. Must be done with no locks held. */ |
| flush_scheduled_work(); |
| |
| blk_cleanup_queue(info->rq); |
| info->rq = NULL; |
| |
| out: |
| xenbus_frontend_closed(dev); |
| } |
| |
| /** |
| * Callback received when the backend's state changes. |
| */ |
| static void backend_changed(struct xenbus_device *dev, |
| enum xenbus_state backend_state) |
| { |
| struct blkfront_info *info = dev->dev.driver_data; |
| struct block_device *bd; |
| |
| dev_dbg(&dev->dev, "blkfront:backend_changed.\n"); |
| |
| switch (backend_state) { |
| case XenbusStateInitialising: |
| case XenbusStateInitWait: |
| case XenbusStateInitialised: |
| case XenbusStateUnknown: |
| case XenbusStateClosed: |
| break; |
| |
| case XenbusStateConnected: |
| blkfront_connect(info); |
| break; |
| |
| case XenbusStateClosing: |
| if (info->gd == NULL) |
| xenbus_dev_fatal(dev, -ENODEV, "gd is NULL"); |
| bd = bdget_disk(info->gd, 0); |
| if (bd == NULL) |
| xenbus_dev_fatal(dev, -ENODEV, "bdget failed"); |
| |
| mutex_lock(&bd->bd_mutex); |
| if (info->users > 0) |
| xenbus_dev_error(dev, -EBUSY, |
| "Device in use; refusing to close"); |
| else |
| blkfront_closing(dev); |
| mutex_unlock(&bd->bd_mutex); |
| bdput(bd); |
| break; |
| } |
| } |
| |
| static int blkfront_remove(struct xenbus_device *dev) |
| { |
| struct blkfront_info *info = dev->dev.driver_data; |
| |
| dev_dbg(&dev->dev, "blkfront_remove: %s removed\n", dev->nodename); |
| |
| blkif_free(info, 0); |
| |
| kfree(info); |
| |
| return 0; |
| } |
| |
| static int blkfront_is_ready(struct xenbus_device *dev) |
| { |
| struct blkfront_info *info = dev->dev.driver_data; |
| |
| return info->is_ready; |
| } |
| |
| static int blkif_open(struct block_device *bdev, fmode_t mode) |
| { |
| struct blkfront_info *info = bdev->bd_disk->private_data; |
| info->users++; |
| return 0; |
| } |
| |
| static int blkif_release(struct gendisk *disk, fmode_t mode) |
| { |
| struct blkfront_info *info = disk->private_data; |
| info->users--; |
| if (info->users == 0) { |
| /* Check whether we have been instructed to close. We will |
| have ignored this request initially, as the device was |
| still mounted. */ |
| struct xenbus_device *dev = info->xbdev; |
| enum xenbus_state state = xenbus_read_driver_state(dev->otherend); |
| |
| if (state == XenbusStateClosing && info->is_ready) |
| blkfront_closing(dev); |
| } |
| return 0; |
| } |
| |
| static struct block_device_operations xlvbd_block_fops = |
| { |
| .owner = THIS_MODULE, |
| .open = blkif_open, |
| .release = blkif_release, |
| .getgeo = blkif_getgeo, |
| .locked_ioctl = blkif_ioctl, |
| }; |
| |
| |
| static struct xenbus_device_id blkfront_ids[] = { |
| { "vbd" }, |
| { "" } |
| }; |
| |
| static struct xenbus_driver blkfront = { |
| .name = "vbd", |
| .owner = THIS_MODULE, |
| .ids = blkfront_ids, |
| .probe = blkfront_probe, |
| .remove = blkfront_remove, |
| .resume = blkfront_resume, |
| .otherend_changed = backend_changed, |
| .is_ready = blkfront_is_ready, |
| }; |
| |
| static int __init xlblk_init(void) |
| { |
| if (!xen_domain()) |
| return -ENODEV; |
| |
| if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) { |
| printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n", |
| XENVBD_MAJOR, DEV_NAME); |
| return -ENODEV; |
| } |
| |
| return xenbus_register_frontend(&blkfront); |
| } |
| module_init(xlblk_init); |
| |
| |
| static void __exit xlblk_exit(void) |
| { |
| return xenbus_unregister_driver(&blkfront); |
| } |
| module_exit(xlblk_exit); |
| |
| MODULE_DESCRIPTION("Xen virtual block device frontend"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR); |
| MODULE_ALIAS("xen:vbd"); |
| MODULE_ALIAS("xenblk"); |