--- /dev/null
+/*
+ * 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/slab.h>
+#include <linux/mutex.h>
+#include <linux/scatterlist.h>
+#include <linux/bitmap.h>
+#include <linux/list.h>
+
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+#include <xen/grant_table.h>
+#include <xen/events.h>
+#include <xen/page.h>
+#include <xen/platform_pci.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 grant {
+ grant_ref_t gref;
+ unsigned long pfn;
+ struct list_head node;
+};
+
+struct blk_shadow {
+ struct blkif_request req;
+ struct request *request;
+ struct grant **grants_used;
+ struct grant **indirect_grants;
+ struct scatterlist *sg;
+};
+
+struct split_bio {
+ struct bio *bio;
+ atomic_t pending;
+ int err;
+};
+
+static DEFINE_MUTEX(blkfront_mutex);
+static const struct block_device_operations xlvbd_block_fops;
+
+/*
+ * Maximum number of segments in indirect requests, the actual value used by
+ * the frontend driver is the minimum of this value and the value provided
+ * by the backend driver.
+ */
+
+static unsigned int xen_blkif_max_segments = 32;
+module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
+MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests (default is 32)");
+
+#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, 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
+{
+ spinlock_t io_lock;
+ struct mutex mutex;
+ 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;
+ unsigned int evtchn, irq;
+ struct request_queue *rq;
+ struct work_struct work;
+ struct gnttab_free_callback callback;
+ struct blk_shadow shadow[BLK_RING_SIZE];
+ struct list_head grants;
+ struct list_head indirect_pages;
+ unsigned int persistent_gnts_c;
+ unsigned long shadow_free;
+ unsigned int feature_flush;
+ unsigned int feature_discard:1;
+ unsigned int feature_secdiscard:1;
+ unsigned int discard_granularity;
+ unsigned int discard_alignment;
+ unsigned int feature_persistent:1;
+ unsigned int max_indirect_segments;
+ int is_ready;
+};
+
+static unsigned int nr_minors;
+static unsigned long *minors;
+static DEFINE_SPINLOCK(minor_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 EMULATED_HD_DISK_MINOR_OFFSET (0)
+#define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
+#define EMULATED_SD_DISK_MINOR_OFFSET (0)
+#define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256)
+
+#define DEV_NAME "xvd" /* name in /dev */
+
+#define SEGS_PER_INDIRECT_FRAME \
+ (PAGE_SIZE/sizeof(struct blkif_request_segment))
+#define INDIRECT_GREFS(_segs) \
+ ((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
+
+static int blkfront_setup_indirect(struct blkfront_info *info);
+
+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.u.rw.id;
+ info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
+ return free;
+}
+
+static int add_id_to_freelist(struct blkfront_info *info,
+ unsigned long id)
+{
+ if (info->shadow[id].req.u.rw.id != id)
+ return -EINVAL;
+ if (info->shadow[id].request == NULL)
+ return -EINVAL;
+ info->shadow[id].req.u.rw.id = info->shadow_free;
+ info->shadow[id].request = NULL;
+ info->shadow_free = id;
+ return 0;
+}
+
+static int fill_grant_buffer(struct blkfront_info *info, int num)
+{
+ struct page *granted_page;
+ struct grant *gnt_list_entry, *n;
+ int i = 0;
+
+ while(i < num) {
+ gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO);
+ if (!gnt_list_entry)
+ goto out_of_memory;
+
+ if (info->feature_persistent) {
+ granted_page = alloc_page(GFP_NOIO);
+ if (!granted_page) {
+ kfree(gnt_list_entry);
+ goto out_of_memory;
+ }
+ gnt_list_entry->pfn = page_to_pfn(granted_page);
+ }
+
+ gnt_list_entry->gref = GRANT_INVALID_REF;
+ list_add(&gnt_list_entry->node, &info->grants);
+ i++;
+ }
+
+ return 0;
+
+out_of_memory:
+ list_for_each_entry_safe(gnt_list_entry, n,
+ &info->grants, node) {
+ list_del(&gnt_list_entry->node);
+ if (info->feature_persistent)
+ __free_page(pfn_to_page(gnt_list_entry->pfn));
+ kfree(gnt_list_entry);
+ i--;
+ }
+ BUG_ON(i != 0);
+ return -ENOMEM;
+}
+
+static struct grant *get_grant(grant_ref_t *gref_head,
+ unsigned long pfn,
+ struct blkfront_info *info)
+{
+ struct grant *gnt_list_entry;
+ unsigned long buffer_mfn;
+
+ BUG_ON(list_empty(&info->grants));
+ gnt_list_entry = list_first_entry(&info->grants, struct grant,
+ node);
+ list_del(&gnt_list_entry->node);
+
+ if (gnt_list_entry->gref != GRANT_INVALID_REF) {
+ info->persistent_gnts_c--;
+ return gnt_list_entry;
+ }
+
+ /* Assign a gref to this page */
+ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
+ BUG_ON(gnt_list_entry->gref == -ENOSPC);
+ if (!info->feature_persistent) {
+ BUG_ON(!pfn);
+ gnt_list_entry->pfn = pfn;
+ }
+ buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
+ gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
+ info->xbdev->otherend_id,
+ buffer_mfn, 0);
+ return gnt_list_entry;
+}
+
+static const char *op_name(int op)
+{
+ static const char *const names[] = {
+ [BLKIF_OP_READ] = "read",
+ [BLKIF_OP_WRITE] = "write",
+ [BLKIF_OP_WRITE_BARRIER] = "barrier",
+ [BLKIF_OP_FLUSH_DISKCACHE] = "flush",
+ [BLKIF_OP_DISCARD] = "discard" };
+
+ if (op < 0 || op >= ARRAY_SIZE(names))
+ return "unknown";
+
+ if (!names[op])
+ return "reserved";
+
+ return names[op];
+}
+static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
+{
+ unsigned int end = minor + nr;
+ int rc;
+
+ if (end > nr_minors) {
+ unsigned long *bitmap, *old;
+
+ bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
+ GFP_KERNEL);
+ if (bitmap == NULL)
+ return -ENOMEM;
+
+ spin_lock(&minor_lock);
+ if (end > nr_minors) {
+ old = minors;
+ memcpy(bitmap, minors,
+ BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
+ minors = bitmap;
+ nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
+ } else
+ old = bitmap;
+ spin_unlock(&minor_lock);
+ kfree(old);
+ }
+
+ spin_lock(&minor_lock);
+ if (find_next_bit(minors, end, minor) >= end) {
+ bitmap_set(minors, minor, nr);
+ rc = 0;
+ } else
+ rc = -EBUSY;
+ spin_unlock(&minor_lock);
+
+ return rc;
+}
+
+static void xlbd_release_minors(unsigned int minor, unsigned int nr)
+{
+ unsigned int end = minor + nr;
+
+ BUG_ON(end > nr_minors);
+ spin_lock(&minor_lock);
+ bitmap_clear(minors, minor, nr);
+ spin_unlock(&minor_lock);
+}
+
+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;
+}
+
+/*
+ * Generate a Xen blkfront IO request from a blk layer request. Reads
+ * and writes are handled as expected.
+ *
+ * @req: a request struct
+ */
+static int blkif_queue_request(struct request *req)
+{
+ struct blkfront_info *info = req->rq_disk->private_data;
+ struct blkif_request *ring_req;
+ unsigned long id;
+ unsigned int fsect, lsect;
+ int i, ref, n;
+ struct blkif_request_segment *segments = NULL;
+
+ /*
+ * Used to store if we are able to queue the request by just using
+ * existing persistent grants, or if we have to get new grants,
+ * as there are not sufficiently many free.
+ */
+ bool new_persistent_gnts;
+ grant_ref_t gref_head;
+ struct grant *gnt_list_entry = NULL;
+ struct scatterlist *sg;
+ int nseg, max_grefs;
+
+ if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
+ return 1;
+
+ max_grefs = req->nr_phys_segments;
+ if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST)
+ /*
+ * If we are using indirect segments we need to account
+ * for the indirect grefs used in the request.
+ */
+ max_grefs += INDIRECT_GREFS(req->nr_phys_segments);
+
+ /* Check if we have enough grants to allocate a requests */
+ if (info->persistent_gnts_c < max_grefs) {
+ new_persistent_gnts = 1;
+ if (gnttab_alloc_grant_references(
+ max_grefs - info->persistent_gnts_c,
+ &gref_head) < 0) {
+ gnttab_request_free_callback(
+ &info->callback,
+ blkif_restart_queue_callback,
+ info,
+ max_grefs);
+ return 1;
+ }
+ } else
+ new_persistent_gnts = 0;
+
+ /* 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 = req;
+
+ if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) {
+ ring_req->operation = BLKIF_OP_DISCARD;
+ ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
+ ring_req->u.discard.id = id;
+ ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req);
+ if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
+ ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
+ else
+ ring_req->u.discard.flag = 0;
+ } else {
+ BUG_ON(info->max_indirect_segments == 0 &&
+ req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ BUG_ON(info->max_indirect_segments &&
+ req->nr_phys_segments > info->max_indirect_segments);
+ nseg = blk_rq_map_sg(req->q, req, info->shadow[id].sg);
+ ring_req->u.rw.id = id;
+ if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) {
+ /*
+ * The indirect operation can only be a BLKIF_OP_READ or
+ * BLKIF_OP_WRITE
+ */
+ BUG_ON(req->cmd_flags & (REQ_FLUSH | REQ_FUA));
+ ring_req->operation = BLKIF_OP_INDIRECT;
+ ring_req->u.indirect.indirect_op = rq_data_dir(req) ?
+ BLKIF_OP_WRITE : BLKIF_OP_READ;
+ ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req);
+ ring_req->u.indirect.handle = info->handle;
+ ring_req->u.indirect.nr_segments = nseg;
+ } else {
+ ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
+ ring_req->u.rw.handle = info->handle;
+ ring_req->operation = rq_data_dir(req) ?
+ BLKIF_OP_WRITE : BLKIF_OP_READ;
+ if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
+ /*
+ * Ideally we can do an unordered flush-to-disk. In case the
+ * backend onlysupports barriers, use that. A barrier request
+ * a superset of FUA, so we can implement it the same
+ * way. (It's also a FLUSH+FUA, since it is
+ * guaranteed ordered WRT previous writes.)
+ */
+ switch (info->feature_flush &
+ ((REQ_FLUSH|REQ_FUA))) {
+ case REQ_FLUSH|REQ_FUA:
+ ring_req->operation =
+ BLKIF_OP_WRITE_BARRIER;
+ break;
+ case REQ_FLUSH:
+ ring_req->operation =
+ BLKIF_OP_FLUSH_DISKCACHE;
+ break;
+ default:
+ ring_req->operation = 0;
+ }
+ }
+ ring_req->u.rw.nr_segments = nseg;
+ }
+ for_each_sg(info->shadow[id].sg, sg, nseg, i) {
+ fsect = sg->offset >> 9;
+ lsect = fsect + (sg->length >> 9) - 1;
+
+ if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
+ (i % SEGS_PER_INDIRECT_FRAME == 0)) {
+ unsigned long uninitialized_var(pfn);
+
+ if (segments)
+ kunmap_atomic(segments);
+
+ n = i / SEGS_PER_INDIRECT_FRAME;
+ if (!info->feature_persistent) {
+ struct page *indirect_page;
+
+ /* Fetch a pre-allocated page to use for indirect grefs */
+ BUG_ON(list_empty(&info->indirect_pages));
+ indirect_page = list_first_entry(&info->indirect_pages,
+ struct page, lru);
+ list_del(&indirect_page->lru);
+ pfn = page_to_pfn(indirect_page);
+ }
+ gnt_list_entry = get_grant(&gref_head, pfn, info);
+ info->shadow[id].indirect_grants[n] = gnt_list_entry;
+ segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
+ ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
+ }
+
+ gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info);
+ ref = gnt_list_entry->gref;
+
+ info->shadow[id].grants_used[i] = gnt_list_entry;
+
+ if (rq_data_dir(req) && info->feature_persistent) {
+ char *bvec_data;
+ void *shared_data;
+
+ BUG_ON(sg->offset + sg->length > PAGE_SIZE);
+
+ shared_data = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
+ bvec_data = kmap_atomic(sg_page(sg));
+
+ /*
+ * this does not wipe data stored outside the
+ * range sg->offset..sg->offset+sg->length.
+ * Therefore, blkback *could* see data from
+ * previous requests. This is OK as long as
+ * persistent grants are shared with just one
+ * domain. It may need refactoring if this
+ * changes
+ */
+ memcpy(shared_data + sg->offset,
+ bvec_data + sg->offset,
+ sg->length);
+
+ kunmap_atomic(bvec_data);
+ kunmap_atomic(shared_data);
+ }
+ if (ring_req->operation != BLKIF_OP_INDIRECT) {
+ ring_req->u.rw.seg[i] =
+ (struct blkif_request_segment) {
+ .gref = ref,
+ .first_sect = fsect,
+ .last_sect = lsect };
+ } else {
+ n = i % SEGS_PER_INDIRECT_FRAME;
+ segments[n] =
+ (struct blkif_request_segment) {
+ .gref = ref,
+ .first_sect = fsect,
+ .last_sect = lsect };
+ }
+ }
+ if (segments)
+ kunmap_atomic(segments);
+ }
+
+ info->ring.req_prod_pvt++;
+
+ /* Keep a private copy so we can reissue requests when recovering. */
+ info->shadow[id].req = *ring_req;
+
+ if (new_persistent_gnts)
+ 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);
+}
+
+static inline bool blkif_request_flush_invalid(struct request *req,
+ struct blkfront_info *info)
+{
+ return ((req->cmd_type != REQ_TYPE_FS) ||
+ ((req->cmd_flags & REQ_FLUSH) &&
+ !(info->feature_flush & REQ_FLUSH)) ||
+ ((req->cmd_flags & REQ_FUA) &&
+ !(info->feature_flush & REQ_FUA)));
+}
+
+/*
+ * 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 = blk_peek_request(rq)) != NULL) {
+ info = req->rq_disk->private_data;
+
+ if (RING_FULL(&info->ring))
+ goto wait;
+
+ blk_start_request(req);
+
+ if (blkif_request_flush_invalid(req, info)) {
+ __blk_end_request_all(req, -EOPNOTSUPP);
+ continue;
+ }
+
+ pr_debug("do_blk_req %p: cmd %p, sec %lx, "
+ "(%u/%u) [%s]\n",
+ req, req->cmd, (unsigned long)blk_rq_pos(req),
+ blk_rq_cur_sectors(req), blk_rq_sectors(req),
+ rq_data_dir(req) ? "write" : "read");
+
+ 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,
+ unsigned int physical_sector_size,
+ unsigned int segments)
+{
+ struct request_queue *rq;
+ struct blkfront_info *info = gd->private_data;
+
+ rq = blk_init_queue(do_blkif_request, &info->io_lock);
+ if (rq == NULL)
+ return -1;
+
+ queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
+
+ if (info->feature_discard) {
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
+ blk_queue_max_discard_sectors(rq, get_capacity(gd));
+ rq->limits.discard_granularity = info->discard_granularity;
+ rq->limits.discard_alignment = info->discard_alignment;
+ if (info->feature_secdiscard)
+ queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq);
+ }
+
+ /* Hard sector size and max sectors impersonate the equiv. hardware. */
+ blk_queue_logical_block_size(rq, sector_size);
+ blk_queue_physical_block_size(rq, physical_sector_size);
+ blk_queue_max_hw_sectors(rq, (segments * PAGE_SIZE) / 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_segments(rq, segments);
+
+ /* 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 const char *flush_info(unsigned int feature_flush)
+{
+ switch (feature_flush & ((REQ_FLUSH | REQ_FUA))) {
+ case REQ_FLUSH|REQ_FUA:
+ return "barrier: enabled;";
+ case REQ_FLUSH:
+ return "flush diskcache: enabled;";
+ default:
+ return "barrier or flush: disabled;";
+ }
+}
+
+static void xlvbd_flush(struct blkfront_info *info)
+{
+ blk_queue_flush(info->rq, info->feature_flush);
+ pr_info("blkfront: %s: %s %s %s %s %s\n",
+ info->gd->disk_name, flush_info(info->feature_flush),
+ "persistent grants:", info->feature_persistent ?
+ "enabled;" : "disabled;", "indirect descriptors:",
+ info->max_indirect_segments ? "enabled;" : "disabled;");
+}
+
+static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
+{
+ int major;
+ major = BLKIF_MAJOR(vdevice);
+ *minor = BLKIF_MINOR(vdevice);
+ switch (major) {
+ case XEN_IDE0_MAJOR:
+ *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
+ *minor = ((*minor / 64) * PARTS_PER_DISK) +
+ EMULATED_HD_DISK_MINOR_OFFSET;
+ break;
+ case XEN_IDE1_MAJOR:
+ *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET;
+ *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
+ EMULATED_HD_DISK_MINOR_OFFSET;
+ break;
+ case XEN_SCSI_DISK0_MAJOR:
+ *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET;
+ *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
+ break;
+ case XEN_SCSI_DISK1_MAJOR:
+ case XEN_SCSI_DISK2_MAJOR:
+ case XEN_SCSI_DISK3_MAJOR:
+ case XEN_SCSI_DISK4_MAJOR:
+ case XEN_SCSI_DISK5_MAJOR:
+ case XEN_SCSI_DISK6_MAJOR:
+ case XEN_SCSI_DISK7_MAJOR:
+ *offset = (*minor / PARTS_PER_DISK) +
+ ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
+ EMULATED_SD_DISK_NAME_OFFSET;
+ *minor = *minor +
+ ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) +
+ EMULATED_SD_DISK_MINOR_OFFSET;
+ break;
+ case XEN_SCSI_DISK8_MAJOR:
+ case XEN_SCSI_DISK9_MAJOR:
+ case XEN_SCSI_DISK10_MAJOR:
+ case XEN_SCSI_DISK11_MAJOR:
+ case XEN_SCSI_DISK12_MAJOR:
+ case XEN_SCSI_DISK13_MAJOR:
+ case XEN_SCSI_DISK14_MAJOR:
+ case XEN_SCSI_DISK15_MAJOR:
+ *offset = (*minor / PARTS_PER_DISK) +
+ ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
+ EMULATED_SD_DISK_NAME_OFFSET;
+ *minor = *minor +
+ ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) +
+ EMULATED_SD_DISK_MINOR_OFFSET;
+ break;
+ case XENVBD_MAJOR:
+ *offset = *minor / PARTS_PER_DISK;
+ break;
+ default:
+ printk(KERN_WARNING "blkfront: your disk configuration is "
+ "incorrect, please use an xvd device instead\n");
+ return -ENODEV;
+ }
+ return 0;
+}
+
+static char *encode_disk_name(char *ptr, unsigned int n)
+{
+ if (n >= 26)
+ ptr = encode_disk_name(ptr, n / 26 - 1);
+ *ptr = 'a' + n % 26;
+ return ptr + 1;
+}
+
+static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
+ struct blkfront_info *info,
+ u16 vdisk_info, u16 sector_size,
+ unsigned int physical_sector_size)
+{
+ struct gendisk *gd;
+ int nr_minors = 1;
+ int err;
+ unsigned int offset;
+ int minor;
+ int nr_parts;
+ char *ptr;
+
+ 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)) {
+ err = xen_translate_vdev(info->vdevice, &minor, &offset);
+ if (err)
+ return err;
+ nr_parts = PARTS_PER_DISK;
+ } else {
+ minor = BLKIF_MINOR_EXT(info->vdevice);
+ nr_parts = PARTS_PER_EXT_DISK;
+ offset = minor / nr_parts;
+ if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4)
+ printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with "
+ "emulated IDE disks,\n\t choose an xvd device name"
+ "from xvde on\n", info->vdevice);
+ }
+ if (minor >> MINORBITS) {
+ pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n",
+ info->vdevice, minor);
+ return -ENODEV;
+ }
+
+ if ((minor % nr_parts) == 0)
+ nr_minors = nr_parts;
+
+ err = xlbd_reserve_minors(minor, nr_minors);
+ if (err)
+ goto out;
+ err = -ENODEV;
+
+ gd = alloc_disk(nr_minors);
+ if (gd == NULL)
+ goto release;
+
+ strcpy(gd->disk_name, DEV_NAME);
+ ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset);
+ BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN);
+ if (nr_minors > 1)
+ *ptr = 0;
+ else
+ snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr,
+ "%d", 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, physical_sector_size,
+ info->max_indirect_segments ? :
+ BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
+ del_gendisk(gd);
+ goto release;
+ }
+
+ info->rq = gd->queue;
+ info->gd = gd;
+
+ xlvbd_flush(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;
+
+ release:
+ xlbd_release_minors(minor, nr_minors);
+ out:
+ return err;
+}
+
+static void xlvbd_release_gendisk(struct blkfront_info *info)
+{
+ unsigned int minor, nr_minors;
+ unsigned long flags;
+
+ if (info->rq == NULL)
+ return;
+
+ spin_lock_irqsave(&info->io_lock, flags);
+
+ /* No more blkif_request(). */
+ blk_stop_queue(info->rq);
+
+ /* No more gnttab callback work. */
+ gnttab_cancel_free_callback(&info->callback);
+ spin_unlock_irqrestore(&info->io_lock, flags);
+
+ /* Flush gnttab callback work. Must be done with no locks held. */
+ flush_work(&info->work);
+
+ del_gendisk(info->gd);
+
+ minor = info->gd->first_minor;
+ nr_minors = info->gd->minors;
+ xlbd_release_minors(minor, nr_minors);
+
+ blk_cleanup_queue(info->rq);
+ info->rq = NULL;
+
+ put_disk(info->gd);
+ info->gd = NULL;
+}
+
+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(&info->io_lock);
+ if (info->connected == BLKIF_STATE_CONNECTED)
+ kick_pending_request_queues(info);
+ spin_unlock_irq(&info->io_lock);
+}
+
+static void blkif_free(struct blkfront_info *info, int suspend)
+{
+ struct grant *persistent_gnt;
+ struct grant *n;
+ int i, j, segs;
+
+ /* Prevent new requests being issued until we fix things up. */
+ spin_lock_irq(&info->io_lock);
+ info->connected = suspend ?
+ BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
+ /* No more blkif_request(). */
+ if (info->rq)
+ blk_stop_queue(info->rq);
+
+ /* Remove all persistent grants */
+ if (!list_empty(&info->grants)) {
+ list_for_each_entry_safe(persistent_gnt, n,
+ &info->grants, node) {
+ list_del(&persistent_gnt->node);
+ if (persistent_gnt->gref != GRANT_INVALID_REF) {
+ gnttab_end_foreign_access(persistent_gnt->gref,
+ 0, 0UL);
+ info->persistent_gnts_c--;
+ }
+ if (info->feature_persistent)
+ __free_page(pfn_to_page(persistent_gnt->pfn));
+ kfree(persistent_gnt);
+ }
+ }
+ BUG_ON(info->persistent_gnts_c != 0);
+
+ /*
+ * Remove indirect pages, this only happens when using indirect
+ * descriptors but not persistent grants
+ */
+ if (!list_empty(&info->indirect_pages)) {
+ struct page *indirect_page, *n;
+
+ BUG_ON(info->feature_persistent);
+ list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
+ list_del(&indirect_page->lru);
+ __free_page(indirect_page);
+ }
+ }
+
+ for (i = 0; i < BLK_RING_SIZE; i++) {
+ /*
+ * Clear persistent grants present in requests already
+ * on the shared ring
+ */
+ if (!info->shadow[i].request)
+ goto free_shadow;
+
+ segs = info->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
+ info->shadow[i].req.u.indirect.nr_segments :
+ info->shadow[i].req.u.rw.nr_segments;
+ for (j = 0; j < segs; j++) {
+ persistent_gnt = info->shadow[i].grants_used[j];
+ gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
+ if (info->feature_persistent)
+ __free_page(pfn_to_page(persistent_gnt->pfn));
+ kfree(persistent_gnt);
+ }
+
+ if (info->shadow[i].req.operation != BLKIF_OP_INDIRECT)
+ /*
+ * If this is not an indirect operation don't try to
+ * free indirect segments
+ */
+ goto free_shadow;
+
+ for (j = 0; j < INDIRECT_GREFS(segs); j++) {
+ persistent_gnt = info->shadow[i].indirect_grants[j];
+ gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
+ __free_page(pfn_to_page(persistent_gnt->pfn));
+ kfree(persistent_gnt);
+ }
+
+free_shadow:
+ kfree(info->shadow[i].grants_used);
+ info->shadow[i].grants_used = NULL;
+ kfree(info->shadow[i].indirect_grants);
+ info->shadow[i].indirect_grants = NULL;
+ kfree(info->shadow[i].sg);
+ info->shadow[i].sg = NULL;
+ }
+
+ /* No more gnttab callback work. */
+ gnttab_cancel_free_callback(&info->callback);
+ spin_unlock_irq(&info->io_lock);
+
+ /* Flush gnttab callback work. Must be done with no locks held. */
+ flush_work(&info->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, struct blkfront_info *info,
+ struct blkif_response *bret)
+{
+ int i = 0;
+ struct scatterlist *sg;
+ char *bvec_data;
+ void *shared_data;
+ int nseg;
+
+ nseg = s->req.operation == BLKIF_OP_INDIRECT ?
+ s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
+
+ if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
+ /*
+ * Copy the data received from the backend into the bvec.
+ * Since bv_offset can be different than 0, and bv_len different
+ * than PAGE_SIZE, we have to keep track of the current offset,
+ * to be sure we are copying the data from the right shared page.
+ */
+ for_each_sg(s->sg, sg, nseg, i) {
+ BUG_ON(sg->offset + sg->length > PAGE_SIZE);
+ shared_data = kmap_atomic(
+ pfn_to_page(s->grants_used[i]->pfn));
+ bvec_data = kmap_atomic(sg_page(sg));
+ memcpy(bvec_data + sg->offset,
+ shared_data + sg->offset,
+ sg->length);
+ kunmap_atomic(bvec_data);
+ kunmap_atomic(shared_data);
+ }
+ }
+ /* Add the persistent grant into the list of free grants */
+ for (i = 0; i < nseg; i++) {
+ if (gnttab_query_foreign_access(s->grants_used[i]->gref)) {
+ /*
+ * If the grant is still mapped by the backend (the
+ * backend has chosen to make this grant persistent)
+ * we add it at the head of the list, so it will be
+ * reused first.
+ */
+ if (!info->feature_persistent)
+ pr_alert_ratelimited("backed has not unmapped grant: %u\n",
+ s->grants_used[i]->gref);
+ list_add(&s->grants_used[i]->node, &info->grants);
+ info->persistent_gnts_c++;
+ } else {
+ /*
+ * If the grant is not mapped by the backend we end the
+ * foreign access and add it to the tail of the list,
+ * so it will not be picked again unless we run out of
+ * persistent grants.
+ */
+ gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL);
+ s->grants_used[i]->gref = GRANT_INVALID_REF;
+ list_add_tail(&s->grants_used[i]->node, &info->grants);
+ }
+ }
+ if (s->req.operation == BLKIF_OP_INDIRECT) {
+ for (i = 0; i < INDIRECT_GREFS(nseg); i++) {
+ if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) {
+ if (!info->feature_persistent)
+ pr_alert_ratelimited("backed has not unmapped grant: %u\n",
+ s->indirect_grants[i]->gref);
+ list_add(&s->indirect_grants[i]->node, &info->grants);
+ info->persistent_gnts_c++;
+ } else {
+ struct page *indirect_page;
+
+ gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL);
+ /*
+ * Add the used indirect page back to the list of
+ * available pages for indirect grefs.
+ */
+ indirect_page = pfn_to_page(s->indirect_grants[i]->pfn);
+ list_add(&indirect_page->lru, &info->indirect_pages);
+ s->indirect_grants[i]->gref = GRANT_INVALID_REF;
+ list_add_tail(&s->indirect_grants[i]->node, &info->grants);
+ }
+ }
+ }
+}
+
+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(&info->io_lock, flags);
+
+ if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
+ spin_unlock_irqrestore(&info->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;
+ /*
+ * The backend has messed up and given us an id that we would
+ * never have given to it (we stamp it up to BLK_RING_SIZE -
+ * look in get_id_from_freelist.
+ */
+ if (id >= BLK_RING_SIZE) {
+ WARN(1, "%s: response to %s has incorrect id (%ld)\n",
+ info->gd->disk_name, op_name(bret->operation), id);
+ /* We can't safely get the 'struct request' as
+ * the id is busted. */
+ continue;
+ }
+ req = info->shadow[id].request;
+
+ if (bret->operation != BLKIF_OP_DISCARD)
+ blkif_completion(&info->shadow[id], info, bret);
+
+ if (add_id_to_freelist(info, id)) {
+ WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
+ info->gd->disk_name, op_name(bret->operation), id);
+ continue;
+ }
+
+ error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
+ switch (bret->operation) {
+ case BLKIF_OP_DISCARD:
+ if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
+ struct request_queue *rq = info->rq;
+ printk(KERN_WARNING "blkfront: %s: %s op failed\n",
+ info->gd->disk_name, op_name(bret->operation));
+ error = -EOPNOTSUPP;
+ info->feature_discard = 0;
+ info->feature_secdiscard = 0;
+ queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
+ queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
+ }
+ __blk_end_request_all(req, error);
+ break;
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ case BLKIF_OP_WRITE_BARRIER:
+ if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
+ printk(KERN_WARNING "blkfront: %s: %s op failed\n",
+ info->gd->disk_name, op_name(bret->operation));
+ error = -EOPNOTSUPP;
+ }
+ if (unlikely(bret->status == BLKIF_RSP_ERROR &&
+ info->shadow[id].req.u.rw.nr_segments == 0)) {
+ printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
+ info->gd->disk_name, op_name(bret->operation));
+ error = -EOPNOTSUPP;
+ }
+ if (unlikely(error)) {
+ if (error == -EOPNOTSUPP)
+ error = 0;
+ info->feature_flush = 0;
+ xlvbd_flush(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(&info->io_lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+
+static int setup_blkring(struct xenbus_device *dev,
+ struct blkfront_info *info)
+{
+ struct blkif_sring *sring;
+ grant_ref_t gref;
+ 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);
+
+ err = xenbus_grant_ring(dev, info->ring.sring, 1, &gref);
+ if (err < 0) {
+ free_page((unsigned long)sring);
+ info->ring.sring = NULL;
+ goto fail;
+ }
+ info->ring_ref = gref;
+
+ err = xenbus_alloc_evtchn(dev, &info->evtchn);
+ if (err)
+ goto fail;
+
+ err = bind_evtchn_to_irqhandler(info->evtchn, blkif_interrupt, 0,
+ "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_blkback(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_printf(xbt, dev->nodename,
+ "feature-persistent", "%u", 1);
+ if (err)
+ dev_warn(&dev->dev,
+ "writing persistent grants feature to xenbus");
+
+ 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;
+ }
+ }
+
+ if (xen_hvm_domain()) {
+ char *type;
+ int len;
+ /* no unplug has been done: do not hook devices != xen vbds */
+ if (xen_has_pv_and_legacy_disk_devices()) {
+ int major;
+
+ if (!VDEV_IS_EXTENDED(vdevice))
+ major = BLKIF_MAJOR(vdevice);
+ else
+ major = XENVBD_MAJOR;
+
+ if (major != XENVBD_MAJOR) {
+ printk(KERN_INFO
+ "%s: HVM does not support vbd %d as xen block device\n",
+ __func__, vdevice);
+ return -ENODEV;
+ }
+ }
+ /* do not create a PV cdrom device if we are an HVM guest */
+ type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
+ if (IS_ERR(type))
+ return -ENODEV;
+ if (strncmp(type, "cdrom", 5) == 0) {
+ kfree(type);
+ return -ENODEV;
+ }
+ kfree(type);
+ }
+ info = kzalloc(sizeof(*info), GFP_KERNEL);
+ if (!info) {
+ xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
+ return -ENOMEM;
+ }
+
+ mutex_init(&info->mutex);
+ spin_lock_init(&info->io_lock);
+ info->xbdev = dev;
+ info->vdevice = vdevice;
+ INIT_LIST_HEAD(&info->grants);
+ INIT_LIST_HEAD(&info->indirect_pages);
+ info->persistent_gnts_c = 0;
+ info->connected = BLKIF_STATE_DISCONNECTED;
+ INIT_WORK(&info->work, blkif_restart_queue);
+
+ for (i = 0; i < BLK_RING_SIZE; i++)
+ info->shadow[i].req.u.rw.id = i+1;
+ info->shadow[BLK_RING_SIZE-1].req.u.rw.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_set_drvdata(&dev->dev, info);
+
+ err = talk_to_blkback(dev, info);
+ if (err) {
+ kfree(info);
+ dev_set_drvdata(&dev->dev, NULL);
+ return err;
+ }
+
+ return 0;
+}
+
+static void split_bio_end(struct bio *bio, int error)
+{
+ struct split_bio *split_bio = bio->bi_private;
+
+ if (error)
+ split_bio->err = error;
+
+ if (atomic_dec_and_test(&split_bio->pending)) {
+ split_bio->bio->bi_phys_segments = 0;
+ bio_endio(split_bio->bio, split_bio->err);
+ kfree(split_bio);
+ }
+ bio_put(bio);
+}
+
+static int blkif_recover(struct blkfront_info *info)
+{
+ int i;
+ struct request *req, *n;
+ struct blk_shadow *copy;
+ int rc;
+ struct bio *bio, *cloned_bio;
+ struct bio_list bio_list, merge_bio;
+ unsigned int segs, offset;
+ int pending, size;
+ struct split_bio *split_bio;
+ struct list_head requests;
+
+ /* Stage 1: Make a safe copy of the shadow state. */
+ copy = kmemdup(info->shadow, sizeof(info->shadow),
+ GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
+ if (!copy)
+ return -ENOMEM;
+
+ /* 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.u.rw.id = i+1;
+ info->shadow_free = info->ring.req_prod_pvt;
+ info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
+
+ rc = blkfront_setup_indirect(info);
+ if (rc) {
+ kfree(copy);
+ return rc;
+ }
+
+ segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ blk_queue_max_segments(info->rq, segs);
+ bio_list_init(&bio_list);
+ INIT_LIST_HEAD(&requests);
+ for (i = 0; i < BLK_RING_SIZE; i++) {
+ /* Not in use? */
+ if (!copy[i].request)
+ continue;
+
+ /*
+ * Get the bios in the request so we can re-queue them.
+ */
+ if (copy[i].request->cmd_flags &
+ (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
+ /*
+ * Flush operations don't contain bios, so
+ * we need to requeue the whole request
+ */
+ list_add(©[i].request->queuelist, &requests);
+ continue;
+ }
+ merge_bio.head = copy[i].request->bio;
+ merge_bio.tail = copy[i].request->biotail;
+ bio_list_merge(&bio_list, &merge_bio);
+ copy[i].request->bio = NULL;
+ blk_end_request_all(copy[i].request, 0);
+ }
+
+ kfree(copy);
+
+ /*
+ * Empty the queue, this is important because we might have
+ * requests in the queue with more segments than what we
+ * can handle now.
+ */
+ spin_lock_irq(&info->io_lock);
+ while ((req = blk_fetch_request(info->rq)) != NULL) {
+ if (req->cmd_flags &
+ (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
+ list_add(&req->queuelist, &requests);
+ continue;
+ }
+ merge_bio.head = req->bio;
+ merge_bio.tail = req->biotail;
+ bio_list_merge(&bio_list, &merge_bio);
+ req->bio = NULL;
+ if (req->cmd_flags & (REQ_FLUSH | REQ_FUA))
+ pr_alert("diskcache flush request found!\n");
+ __blk_end_request_all(req, 0);
+ }
+ spin_unlock_irq(&info->io_lock);
+
+ xenbus_switch_state(info->xbdev, XenbusStateConnected);
+
+ spin_lock_irq(&info->io_lock);
+
+ /* Now safe for us to use the shared ring */
+ info->connected = BLKIF_STATE_CONNECTED;
+
+ /* Kick any other new requests queued since we resumed */
+ kick_pending_request_queues(info);
+
+ list_for_each_entry_safe(req, n, &requests, queuelist) {
+ /* Requeue pending requests (flush or discard) */
+ list_del_init(&req->queuelist);
+ BUG_ON(req->nr_phys_segments > segs);
+ blk_requeue_request(info->rq, req);
+ }
+ spin_unlock_irq(&info->io_lock);
+
+ while ((bio = bio_list_pop(&bio_list)) != NULL) {
+ /* Traverse the list of pending bios and re-queue them */
+ if (bio_segments(bio) > segs) {
+ /*
+ * This bio has more segments than what we can
+ * handle, we have to split it.
+ */
+ pending = (bio_segments(bio) + segs - 1) / segs;
+ split_bio = kzalloc(sizeof(*split_bio), GFP_NOIO);
+ BUG_ON(split_bio == NULL);
+ atomic_set(&split_bio->pending, pending);
+ split_bio->bio = bio;
+ for (i = 0; i < pending; i++) {
+ offset = (i * segs * PAGE_SIZE) >> 9;
+ size = min((unsigned int)(segs * PAGE_SIZE) >> 9,
+ (unsigned int)bio_sectors(bio) - offset);
+ cloned_bio = bio_clone(bio, GFP_NOIO);
+ BUG_ON(cloned_bio == NULL);
+ bio_trim(cloned_bio, offset, size);
+ cloned_bio->bi_private = split_bio;
+ cloned_bio->bi_end_io = split_bio_end;
+ submit_bio(cloned_bio->bi_rw, cloned_bio);
+ }
+ /*
+ * Now we have to wait for all those smaller bios to
+ * end, so we can also end the "parent" bio.
+ */
+ continue;
+ }
+ /* We don't need to split this bio */
+ submit_bio(bio->bi_rw, bio);
+ }
+
+ 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_get_drvdata(&dev->dev);
+ int err;
+
+ dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
+
+ blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
+
+ err = talk_to_blkback(dev, info);
+
+ /*
+ * We have to wait for the backend to switch to
+ * connected state, since we want to read which
+ * features it supports.
+ */
+
+ return err;
+}
+
+static void
+blkfront_closing(struct blkfront_info *info)
+{
+ struct xenbus_device *xbdev = info->xbdev;
+ struct block_device *bdev = NULL;
+
+ mutex_lock(&info->mutex);
+
+ if (xbdev->state == XenbusStateClosing) {
+ mutex_unlock(&info->mutex);
+ return;
+ }
+
+ if (info->gd)
+ bdev = bdget_disk(info->gd, 0);
+
+ mutex_unlock(&info->mutex);
+
+ if (!bdev) {
+ xenbus_frontend_closed(xbdev);
+ return;
+ }
+
+ mutex_lock(&bdev->bd_mutex);
+
+ if (bdev->bd_openers) {
+ xenbus_dev_error(xbdev, -EBUSY,
+ "Device in use; refusing to close");
+ xenbus_switch_state(xbdev, XenbusStateClosing);
+ } else {
+ xlvbd_release_gendisk(info);
+ xenbus_frontend_closed(xbdev);
+ }
+
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdev);
+}
+
+static void blkfront_setup_discard(struct blkfront_info *info)
+{
+ int err;
+ unsigned int discard_granularity;
+ unsigned int discard_alignment;
+ unsigned int discard_secure;
+
+ info->feature_discard = 1;
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "discard-granularity", "%u", &discard_granularity,
+ "discard-alignment", "%u", &discard_alignment,
+ NULL);
+ if (!err) {
+ info->discard_granularity = discard_granularity;
+ info->discard_alignment = discard_alignment;
+ }
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "discard-secure", "%d", &discard_secure,
+ NULL);
+ if (!err)
+ info->feature_secdiscard = !!discard_secure;
+}
+
+static int blkfront_setup_indirect(struct blkfront_info *info)
+{
+ unsigned int indirect_segments, segs;
+ int err, i;
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-max-indirect-segments", "%u", &indirect_segments,
+ NULL);
+ if (err) {
+ info->max_indirect_segments = 0;
+ segs = BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ } else {
+ info->max_indirect_segments = min(indirect_segments,
+ xen_blkif_max_segments);
+ segs = info->max_indirect_segments;
+ }
+
+ err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * BLK_RING_SIZE);
+ if (err)
+ goto out_of_memory;
+
+ if (!info->feature_persistent && info->max_indirect_segments) {
+ /*
+ * We are using indirect descriptors but not persistent
+ * grants, we need to allocate a set of pages that can be
+ * used for mapping indirect grefs
+ */
+ int num = INDIRECT_GREFS(segs) * BLK_RING_SIZE;
+
+ BUG_ON(!list_empty(&info->indirect_pages));
+ for (i = 0; i < num; i++) {
+ struct page *indirect_page = alloc_page(GFP_NOIO);
+ if (!indirect_page)
+ goto out_of_memory;
+ list_add(&indirect_page->lru, &info->indirect_pages);
+ }
+ }
+
+ for (i = 0; i < BLK_RING_SIZE; i++) {
+ info->shadow[i].grants_used = kzalloc(
+ sizeof(info->shadow[i].grants_used[0]) * segs,
+ GFP_NOIO);
+ info->shadow[i].sg = kzalloc(sizeof(info->shadow[i].sg[0]) * segs, GFP_NOIO);
+ if (info->max_indirect_segments)
+ info->shadow[i].indirect_grants = kzalloc(
+ sizeof(info->shadow[i].indirect_grants[0]) *
+ INDIRECT_GREFS(segs),
+ GFP_NOIO);
+ if ((info->shadow[i].grants_used == NULL) ||
+ (info->shadow[i].sg == NULL) ||
+ (info->max_indirect_segments &&
+ (info->shadow[i].indirect_grants == NULL)))
+ goto out_of_memory;
+ sg_init_table(info->shadow[i].sg, segs);
+ }
+
+
+ return 0;
+
+out_of_memory:
+ for (i = 0; i < BLK_RING_SIZE; i++) {
+ kfree(info->shadow[i].grants_used);
+ info->shadow[i].grants_used = NULL;
+ kfree(info->shadow[i].sg);
+ info->shadow[i].sg = NULL;
+ kfree(info->shadow[i].indirect_grants);
+ info->shadow[i].indirect_grants = NULL;
+ }
+ if (!list_empty(&info->indirect_pages)) {
+ struct page *indirect_page, *n;
+ list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
+ list_del(&indirect_page->lru);
+ __free_page(indirect_page);
+ }
+ }
+ return -ENOMEM;
+}
+
+/*
+ * 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 physical_sector_size;
+ unsigned int binfo;
+ int err;
+ int barrier, flush, discard, persistent;
+
+ switch (info->connected) {
+ case BLKIF_STATE_CONNECTED:
+ /*
+ * Potentially, the back-end may be signalling
+ * a capacity change; update the capacity.
+ */
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "sectors", "%Lu", §ors);
+ if (XENBUS_EXIST_ERR(err))
+ return;
+ printk(KERN_INFO "Setting capacity to %Lu\n",
+ sectors);
+ set_capacity(info->gd, sectors);
+ revalidate_disk(info->gd);
+
+ return;
+ case BLKIF_STATE_SUSPENDED:
+ /*
+ * If we are recovering from suspension, we need to wait
+ * for the backend to announce it's features before
+ * reconnecting, at least we need to know if the backend
+ * supports indirect descriptors, and how many.
+ */
+ blkif_recover(info);
+ return;
+
+ default:
+ break;
+ }
+
+ 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;
+ }
+
+ /*
+ * physcial-sector-size is a newer field, so old backends may not
+ * provide this. Assume physical sector size to be the same as
+ * sector_size in that case.
+ */
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "physical-sector-size", "%u", &physical_sector_size);
+ if (err != 1)
+ physical_sector_size = sector_size;
+
+ info->feature_flush = 0;
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-barrier", "%d", &barrier,
+ NULL);
+
+ /*
+ * If there's no "feature-barrier" defined, then it means
+ * we're dealing with a very old backend which writes
+ * synchronously; nothing to do.
+ *
+ * If there are barriers, then we use flush.
+ */
+ if (!err && barrier)
+ info->feature_flush = REQ_FLUSH | REQ_FUA;
+ /*
+ * And if there is "feature-flush-cache" use that above
+ * barriers.
+ */
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-flush-cache", "%d", &flush,
+ NULL);
+
+ if (!err && flush)
+ info->feature_flush = REQ_FLUSH;
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-discard", "%d", &discard,
+ NULL);
+
+ if (!err && discard)
+ blkfront_setup_discard(info);
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-persistent", "%u", &persistent,
+ NULL);
+ if (err)
+ info->feature_persistent = 0;
+ else
+ info->feature_persistent = persistent;
+
+ err = blkfront_setup_indirect(info);
+ if (err) {
+ xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s",
+ info->xbdev->otherend);
+ return;
+ }
+
+ err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size,
+ physical_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(&info->io_lock);
+ info->connected = BLKIF_STATE_CONNECTED;
+ kick_pending_request_queues(info);
+ spin_unlock_irq(&info->io_lock);
+
+ add_disk(info->gd);
+
+ info->is_ready = 1;
+}
+
+/**
+ * Callback received when the backend's state changes.
+ */
+static void blkback_changed(struct xenbus_device *dev,
+ enum xenbus_state backend_state)
+{
+ struct blkfront_info *info = dev_get_drvdata(&dev->dev);
+
+ dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
+
+ switch (backend_state) {
+ case XenbusStateInitialising:
+ case XenbusStateInitWait:
+ case XenbusStateInitialised:
+ case XenbusStateReconfiguring:
+ case XenbusStateReconfigured:
+ case XenbusStateUnknown:
+ break;
+
+ case XenbusStateConnected:
+ blkfront_connect(info);
+ break;
+
+ case XenbusStateClosed:
+ if (dev->state == XenbusStateClosed)
+ break;
+ /* Missed the backend's Closing state -- fallthrough */
+ case XenbusStateClosing:
+ blkfront_closing(info);
+ break;
+ }
+}
+
+static int blkfront_remove(struct xenbus_device *xbdev)
+{
+ struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
+ struct block_device *bdev = NULL;
+ struct gendisk *disk;
+
+ dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
+
+ blkif_free(info, 0);
+
+ mutex_lock(&info->mutex);
+
+ disk = info->gd;
+ if (disk)
+ bdev = bdget_disk(disk, 0);
+
+ info->xbdev = NULL;
+ mutex_unlock(&info->mutex);
+
+ if (!bdev) {
+ kfree(info);
+ return 0;
+ }
+
+ /*
+ * The xbdev was removed before we reached the Closed
+ * state. See if it's safe to remove the disk. If the bdev
+ * isn't closed yet, we let release take care of it.
+ */
+
+ mutex_lock(&bdev->bd_mutex);
+ info = disk->private_data;
+
+ dev_warn(disk_to_dev(disk),
+ "%s was hot-unplugged, %d stale handles\n",
+ xbdev->nodename, bdev->bd_openers);
+
+ if (info && !bdev->bd_openers) {
+ xlvbd_release_gendisk(info);
+ disk->private_data = NULL;
+ kfree(info);
+ }
+
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdev);
+
+ return 0;
+}
+
+static int blkfront_is_ready(struct xenbus_device *dev)
+{
+ struct blkfront_info *info = dev_get_drvdata(&dev->dev);
+
+ return info->is_ready && info->xbdev;
+}
+
+static int blkif_open(struct block_device *bdev, fmode_t mode)
+{
+ struct gendisk *disk = bdev->bd_disk;
+ struct blkfront_info *info;
+ int err = 0;
+
+ mutex_lock(&blkfront_mutex);
+
+ info = disk->private_data;
+ if (!info) {
+ /* xbdev gone */
+ err = -ERESTARTSYS;
+ goto out;
+ }
+
+ mutex_lock(&info->mutex);
+
+ if (!info->gd)
+ /* xbdev is closed */
+ err = -ERESTARTSYS;
+
+ mutex_unlock(&info->mutex);
+
+out:
+ mutex_unlock(&blkfront_mutex);
+ return err;
+}
+
+static void blkif_release(struct gendisk *disk, fmode_t mode)
+{
+ struct blkfront_info *info = disk->private_data;
+ struct block_device *bdev;
+ struct xenbus_device *xbdev;
+
+ mutex_lock(&blkfront_mutex);
+
+ bdev = bdget_disk(disk, 0);
+
+ if (!bdev) {
+ WARN(1, "Block device %s yanked out from us!\n", disk->disk_name);
+ goto out_mutex;
+ }
+ if (bdev->bd_openers)
+ goto out;
+
+ /*
+ * Check if we have been instructed to close. We will have
+ * deferred this request, because the bdev was still open.
+ */
+
+ mutex_lock(&info->mutex);
+ xbdev = info->xbdev;
+
+ if (xbdev && xbdev->state == XenbusStateClosing) {
+ /* pending switch to state closed */
+ dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
+ xlvbd_release_gendisk(info);
+ xenbus_frontend_closed(info->xbdev);
+ }
+
+ mutex_unlock(&info->mutex);
+
+ if (!xbdev) {
+ /* sudden device removal */
+ dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
+ xlvbd_release_gendisk(info);
+ disk->private_data = NULL;
+ kfree(info);
+ }
+
+out:
+ bdput(bdev);
+out_mutex:
+ mutex_unlock(&blkfront_mutex);
+}
+
+static const struct block_device_operations xlvbd_block_fops =
+{
+ .owner = THIS_MODULE,
+ .open = blkif_open,
+ .release = blkif_release,
+ .getgeo = blkif_getgeo,
+ .ioctl = blkif_ioctl,
+};
+
+
+static const struct xenbus_device_id blkfront_ids[] = {
+ { "vbd" },
+ { "" }
+};
+
+static struct xenbus_driver blkfront_driver = {
+ .ids = blkfront_ids,
+ .probe = blkfront_probe,
+ .remove = blkfront_remove,
+ .resume = blkfront_resume,
+ .otherend_changed = blkback_changed,
+ .is_ready = blkfront_is_ready,
+};
+
+static int __init xlblk_init(void)
+{
+ int ret;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ if (!xen_has_pv_disk_devices())
+ 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;
+ }
+
+ ret = xenbus_register_frontend(&blkfront_driver);
+ if (ret) {
+ unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
+ return ret;
+ }
+
+ return 0;
+}
+module_init(xlblk_init);
+
+
+static void __exit xlblk_exit(void)
+{
+ xenbus_unregister_driver(&blkfront_driver);
+ unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
+ kfree(minors);
+}
+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");
Code Review / kvmfornfv.git / blobdiff