1 /******************************************************************************
2 * drivers/xen/blktap/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
35 #include <xen/evtchn.h>
37 static struct kmem_cache *blkif_cachep;
39 blkif_t *tap_alloc_blkif(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;
63 gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr,
64 GNTMAP_host_map, shared_page, blkif->domid);
66 lock_vm_area(blkif->blk_ring_area);
67 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
68 unlock_vm_area(blkif->blk_ring_area);
72 DPRINTK(" Grant table operation failure !\n");
76 blkif->shmem_ref = shared_page;
77 blkif->shmem_handle = op.handle;
82 static void unmap_frontend_page(blkif_t *blkif)
84 struct gnttab_unmap_grant_ref op;
87 gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr,
88 GNTMAP_host_map, blkif->shmem_handle);
90 lock_vm_area(blkif->blk_ring_area);
91 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
92 unlock_vm_area(blkif->blk_ring_area);
96 int tap_blkif_map(blkif_t *blkif, unsigned long shared_page,
101 struct evtchn_bind_interdomain bind_interdomain;
103 /* Already connected through? */
107 if ( (blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE)) == NULL )
110 err = map_frontend_page(blkif, shared_page);
112 free_vm_area(blkif->blk_ring_area);
116 bind_interdomain.remote_dom = blkif->domid;
117 bind_interdomain.remote_port = evtchn;
119 err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
122 unmap_frontend_page(blkif);
123 free_vm_area(blkif->blk_ring_area);
127 blkif->evtchn = bind_interdomain.local_port;
129 sring = (blkif_sring_t *)blkif->blk_ring_area->addr;
130 BACK_RING_INIT(&blkif->blk_ring, sring, PAGE_SIZE);
132 blkif->irq = bind_evtchn_to_irqhandler(
133 blkif->evtchn, tap_blkif_be_int, 0, "blkif-backend", blkif);
138 void tap_blkif_unmap(blkif_t *blkif)
141 unbind_from_irqhandler(blkif->irq, blkif);
144 if (blkif->blk_ring.sring) {
145 unmap_frontend_page(blkif);
146 free_vm_area(blkif->blk_ring_area);
147 blkif->blk_ring.sring = NULL;
151 void tap_blkif_free(blkif_t *blkif)
153 atomic_dec(&blkif->refcnt);
154 wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
156 tap_blkif_unmap(blkif);
157 kmem_cache_free(blkif_cachep, blkif);
160 void __init tap_blkif_interface_init(void)
162 blkif_cachep = kmem_cache_create("blktapif_cache", sizeof(blkif_t),