1 /******************************************************************************
2 * arch/xen/drivers/blkif/backend/interface.c
4 * Block-device interface management.
6 * Copyright (c) 2004, Keir Fraser
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version 2
10 * as published by the Free Software Foundation; or, when distributed
11 * separately from the Linux kernel or incorporated into other
12 * software packages, subject to the following license:
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this source file (the "Software"), to deal in the Software without
16 * restriction, including without limitation the rights to use, copy, modify,
17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18 * and to permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
34 #include <xen/evtchn.h>
35 #include <linux/kthread.h>
37 static kmem_cache_t *blkif_cachep;
39 blkif_t *blkif_alloc(domid_t domid)
43 blkif = kmem_cache_alloc(blkif_cachep, GFP_KERNEL);
45 return ERR_PTR(-ENOMEM);
47 memset(blkif, 0, sizeof(*blkif));
49 spin_lock_init(&blkif->blk_ring_lock);
50 atomic_set(&blkif->refcnt, 1);
51 init_waitqueue_head(&blkif->wq);
52 blkif->st_print = jiffies;
53 init_waitqueue_head(&blkif->waiting_to_free);
58 static int map_frontend_page(blkif_t *blkif, unsigned long shared_page)
60 struct gnttab_map_grant_ref op;
62 gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr,
63 GNTMAP_host_map, shared_page, blkif->domid);
65 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
69 DPRINTK(" Grant table operation failure !\n");
73 blkif->shmem_ref = shared_page;
74 blkif->shmem_handle = op.handle;
79 static void unmap_frontend_page(blkif_t *blkif)
81 struct gnttab_unmap_grant_ref op;
83 gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr,
84 GNTMAP_host_map, blkif->shmem_handle);
86 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
90 int blkif_map(blkif_t *blkif, unsigned long shared_page, unsigned int evtchn)
94 /* Already connected through? */
98 if ( (blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE)) == NULL )
101 err = map_frontend_page(blkif, shared_page);
103 free_vm_area(blkif->blk_ring_area);
107 switch (blkif->blk_protocol) {
108 case BLKIF_PROTOCOL_NATIVE:
110 blkif_sring_t *sring;
111 sring = (blkif_sring_t *)blkif->blk_ring_area->addr;
112 BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
115 case BLKIF_PROTOCOL_X86_32:
117 blkif_x86_32_sring_t *sring_x86_32;
118 sring_x86_32 = (blkif_x86_32_sring_t *)blkif->blk_ring_area->addr;
119 BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE);
122 case BLKIF_PROTOCOL_X86_64:
124 blkif_x86_64_sring_t *sring_x86_64;
125 sring_x86_64 = (blkif_x86_64_sring_t *)blkif->blk_ring_area->addr;
126 BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);
133 err = bind_interdomain_evtchn_to_irqhandler(
134 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(blkif_t *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(blkif_t *blkif)
172 if (!atomic_dec_and_test(&blkif->refcnt))
174 kmem_cache_free(blkif_cachep, blkif);
177 void __init blkif_interface_init(void)
179 blkif_cachep = kmem_cache_create("blkif_cache", sizeof(blkif_t),