1 /******************************************************************************
2 * Block-device interface management.
4 * Copyright (c) 2004, Keir Fraser
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version 2
8 * as published by the Free Software Foundation; or, when distributed
9 * separately from the Linux kernel or incorporated into other
10 * software packages, subject to the following license:
12 * Permission is hereby granted, free of charge, to any person obtaining a copy
13 * of this source file (the "Software"), to deal in the Software without
14 * restriction, including without limitation the rights to use, copy, modify,
15 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
16 * and to permit persons to whom the Software is furnished to do so, subject to
17 * the following conditions:
19 * The above copyright notice and this permission notice shall be included in
20 * all copies or substantial portions of the Software.
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
32 #include <xen/events.h>
33 #include <xen/grant_table.h>
34 #include <linux/kthread.h>
36 static struct kmem_cache *blkif_cachep;
38 struct blkif_st *blkif_alloc(domid_t domid)
40 struct blkif_st *blkif;
42 blkif = kmem_cache_alloc(blkif_cachep, GFP_KERNEL);
44 return ERR_PTR(-ENOMEM);
46 memset(blkif, 0, sizeof(*blkif));
48 spin_lock_init(&blkif->blk_ring_lock);
49 atomic_set(&blkif->refcnt, 1);
50 init_waitqueue_head(&blkif->wq);
51 blkif->st_print = jiffies;
52 init_waitqueue_head(&blkif->waiting_to_free);
57 static int map_frontend_page(struct blkif_st *blkif, unsigned long shared_page)
59 struct gnttab_map_grant_ref op;
61 gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr,
62 GNTMAP_host_map, shared_page, blkif->domid);
64 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
68 DPRINTK(" Grant table operation failure !\n");
72 blkif->shmem_ref = shared_page;
73 blkif->shmem_handle = op.handle;
78 static void unmap_frontend_page(struct blkif_st *blkif)
80 struct gnttab_unmap_grant_ref op;
82 gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr,
83 GNTMAP_host_map, blkif->shmem_handle);
85 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
89 int blkif_map(struct blkif_st *blkif, unsigned long shared_page,
94 /* Already connected through? */
98 blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE);
99 if (!blkif->blk_ring_area)
102 err = map_frontend_page(blkif, shared_page);
104 free_vm_area(blkif->blk_ring_area);
108 switch (blkif->blk_protocol) {
109 case BLKIF_PROTOCOL_NATIVE:
111 struct blkif_sring *sring;
112 sring = (struct blkif_sring *)blkif->blk_ring_area->addr;
113 BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
116 case BLKIF_PROTOCOL_X86_32:
118 struct blkif_x86_32_sring *sring_x86_32;
119 sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring_area->addr;
120 BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE);
123 case BLKIF_PROTOCOL_X86_64:
125 struct blkif_x86_64_sring *sring_x86_64;
126 sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr;
127 BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);
134 err = bind_interdomain_evtchn_to_irqhandler(
135 blkif->domid, evtchn, blkif_be_int, 0, "blkif-backend", blkif);
137 unmap_frontend_page(blkif);
138 free_vm_area(blkif->blk_ring_area);
139 blkif->blk_rings.common.sring = NULL;
147 void blkif_disconnect(struct blkif_st *blkif)
149 if (blkif->xenblkd) {
150 kthread_stop(blkif->xenblkd);
151 blkif->xenblkd = NULL;
154 atomic_dec(&blkif->refcnt);
155 wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
156 atomic_inc(&blkif->refcnt);
159 unbind_from_irqhandler(blkif->irq, blkif);
163 if (blkif->blk_rings.common.sring) {
164 unmap_frontend_page(blkif);
165 free_vm_area(blkif->blk_ring_area);
166 blkif->blk_rings.common.sring = NULL;
170 void blkif_free(struct blkif_st *blkif)
172 if (!atomic_dec_and_test(&blkif->refcnt))
174 kmem_cache_free(blkif_cachep, blkif);
177 int __init blkif_interface_init(void)
179 blkif_cachep = kmem_cache_create("blkif_cache", sizeof(struct blkif_st),