| /* |
| * 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 persistent_gnts; |
| unsigned int persistent_gnts_c; |
| unsigned long shadow_free; |
| unsigned int feature_flush; |
| unsigned int flush_op; |
| 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_aligned)) |
| #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; |
| |
| 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->persistent_gnts); |
| i++; |
| } |
| |
| return 0; |
| |
| out_of_memory: |
| list_for_each_entry_safe(gnt_list_entry, n, |
| &info->persistent_gnts, node) { |
| list_del(&gnt_list_entry->node); |
| __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, |
| struct blkfront_info *info) |
| { |
| struct grant *gnt_list_entry; |
| unsigned long buffer_mfn; |
| |
| BUG_ON(list_empty(&info->persistent_gnts)); |
| gnt_list_entry = list_first_entry(&info->persistent_gnts, 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); |
| 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_aligned *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 = info->max_indirect_segments ? |
| info->max_indirect_segments + |
| INDIRECT_GREFS(info->max_indirect_segments) : |
| BLKIF_MAX_SEGMENTS_PER_REQUEST; |
| |
| /* 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.) |
| */ |
| ring_req->operation = info->flush_op; |
| } |
| 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)) { |
| if (segments) |
| kunmap_atomic(segments); |
| |
| n = i / SEGS_PER_INDIRECT_FRAME; |
| gnt_list_entry = get_grant(&gref_head, 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, info); |
| ref = gnt_list_entry->gref; |
| |
| info->shadow[id].grants_used[i] = gnt_list_entry; |
| |
| if (rq_data_dir(req)) { |
| 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_aligned) { |
| .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); |
| } |
| |
| /* |
| * 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 ((req->cmd_type != REQ_TYPE_FS) || |
| ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) && |
| !info->flush_op)) { |
| __blk_end_request_all(req, -EIO); |
| continue; |
| } |
| |
| 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"); |
| |
| 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 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_max_hw_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_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 void xlvbd_flush(struct blkfront_info *info) |
| { |
| blk_queue_flush(info->rq, info->feature_flush); |
| printk(KERN_INFO "blkfront: %s: %s: %s %s %s %s %s\n", |
| info->gd->disk_name, |
| info->flush_op == BLKIF_OP_WRITE_BARRIER ? |
| "barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ? |
| "flush diskcache" : "barrier or flush"), |
| info->feature_flush ? "enabled;" : "disabled;", |
| "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) |
| { |
| 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, |
| 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->persistent_gnts)) { |
| list_for_each_entry_safe(persistent_gnt, n, |
| &info->persistent_gnts, 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--; |
| } |
| __free_page(pfn_to_page(persistent_gnt->pfn)); |
| kfree(persistent_gnt); |
| } |
| } |
| BUG_ON(info->persistent_gnts_c != 0); |
| |
| 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); |
| __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) { |
| /* |
| * 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++) { |
| list_add(&s->grants_used[i]->node, &info->persistent_gnts); |
| info->persistent_gnts_c++; |
| } |
| if (s->req.operation == BLKIF_OP_INDIRECT) { |
| for (i = 0; i < INDIRECT_GREFS(nseg); i++) { |
| list_add(&s->indirect_grants[i]->node, &info->persistent_gnts); |
| info->persistent_gnts_c++; |
| } |
| } |
| } |
| |
| 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; |
| info->flush_op = 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; |
| 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, 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, 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_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) { |
| 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", |
| __FUNCTION__, 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->persistent_gnts); |
| 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; |
| } |
| |
| /* |
| * This is a clone of md_trim_bio, used to split a bio into smaller ones |
| */ |
| static void trim_bio(struct bio *bio, int offset, int size) |
| { |
| /* 'bio' is a cloned bio which we need to trim to match |
| * the given offset and size. |
| * This requires adjusting bi_sector, bi_size, and bi_io_vec |
| */ |
| int i; |
| struct bio_vec *bvec; |
| int sofar = 0; |
| |
| size <<= 9; |
| if (offset == 0 && size == bio->bi_size) |
| return; |
| |
| bio->bi_sector += offset; |
| bio->bi_size = size; |
| offset <<= 9; |
| clear_bit(BIO_SEG_VALID, &bio->bi_flags); |
| |
| while (bio->bi_idx < bio->bi_vcnt && |
| bio->bi_io_vec[bio->bi_idx].bv_len <= offset) { |
| /* remove this whole bio_vec */ |
| offset -= bio->bi_io_vec[bio->bi_idx].bv_len; |
| bio->bi_idx++; |
| } |
| if (bio->bi_idx < bio->bi_vcnt) { |
| bio->bi_io_vec[bio->bi_idx].bv_offset += offset; |
| bio->bi_io_vec[bio->bi_idx].bv_len -= offset; |
| } |
| /* avoid any complications with bi_idx being non-zero*/ |
| if (bio->bi_idx) { |
| memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx, |
| (bio->bi_vcnt - bio->bi_idx) * sizeof(struct bio_vec)); |
| bio->bi_vcnt -= bio->bi_idx; |
| bio->bi_idx = 0; |
| } |
| /* Make sure vcnt and last bv are not too big */ |
| bio_for_each_segment(bvec, bio, i) { |
| if (sofar + bvec->bv_len > size) |
| bvec->bv_len = size - sofar; |
| if (bvec->bv_len == 0) { |
| bio->bi_vcnt = i; |
| break; |
| } |
| sofar += bvec->bv_len; |
| } |
| } |
| |
| 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_put_request(copy[i].request); |
| } |
| |
| 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_put_request(info->rq, req); |
| } |
| 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->bi_size >> 9) - offset); |
| cloned_bio = bio_clone(bio, GFP_NOIO); |
| BUG_ON(cloned_bio == NULL); |
| trim_bio(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; |
| char *type; |
| unsigned int discard_granularity; |
| unsigned int discard_alignment; |
| unsigned int discard_secure; |
| |
| type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL); |
| if (IS_ERR(type)) |
| return; |
| |
| info->feature_secdiscard = 0; |
| if (strncmp(type, "phy", 3) == 0) { |
| err = xenbus_gather(XBT_NIL, info->xbdev->otherend, |
| "discard-granularity", "%u", &discard_granularity, |
| "discard-alignment", "%u", &discard_alignment, |
| NULL); |
| if (!err) { |
| info->feature_discard = 1; |
| 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; |
| |
| } else if (strncmp(type, "file", 4) == 0) |
| info->feature_discard = 1; |
| |
| kfree(type); |
| } |
| |
| 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; |
| |
| 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; |
| } |
| 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 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; |
| } |
| |
| info->feature_flush = 0; |
| info->flush_op = 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; |
| info->flush_op = BLKIF_OP_WRITE_BARRIER; |
| } |
| /* |
| * 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; |
| info->flush_op = BLKIF_OP_FLUSH_DISKCACHE; |
| } |
| |
| 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); |
| 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: |
| case XenbusStateClosed: |
| break; |
| |
| case XenbusStateConnected: |
| blkfront_connect(info); |
| break; |
| |
| 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 int 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->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); |
| mutex_unlock(&blkfront_mutex); |
| return 0; |
| } |
| |
| 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 DEFINE_XENBUS_DRIVER(blkfront, , |
| .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_hvm_domain() && !xen_platform_pci_unplug) |
| 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"); |