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>
36 #include <linux/vmalloc.h>
38 static struct kmem_cache *blkif_cachep;
40 blkif_t *tap_alloc_blkif(domid_t domid)
44 blkif = kmem_cache_zalloc(blkif_cachep, GFP_KERNEL);
46 return ERR_PTR(-ENOMEM);
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 int tap_blkif_map(blkif_t *blkif, struct xenbus_device *dev,
59 grant_ref_t ring_ref, evtchn_port_t evtchn)
61 struct vm_struct *area;
64 /* Already connected through? */
68 area = xenbus_map_ring_valloc(dev, ring_ref);
71 blkif->blk_ring_area = area;
73 switch (blkif->blk_protocol) {
74 case BLKIF_PROTOCOL_NATIVE:
77 sring = (blkif_sring_t *)area->addr;
78 BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
81 case BLKIF_PROTOCOL_X86_32:
83 blkif_x86_32_sring_t *sring_x86_32;
84 sring_x86_32 = (blkif_x86_32_sring_t *)area->addr;
85 BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE);
88 case BLKIF_PROTOCOL_X86_64:
90 blkif_x86_64_sring_t *sring_x86_64;
91 sring_x86_64 = (blkif_x86_64_sring_t *)area->addr;
92 BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);
99 err = bind_interdomain_evtchn_to_irqhandler(
100 blkif->domid, evtchn, tap_blkif_be_int,
101 0, "blkif-backend", blkif);
103 xenbus_unmap_ring_vfree(dev, area);
104 blkif->blk_rings.common.sring = NULL;
112 void tap_blkif_free(blkif_t *blkif, struct xenbus_device *dev)
114 atomic_dec(&blkif->refcnt);
115 wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
116 atomic_inc(&blkif->refcnt);
119 unbind_from_irqhandler(blkif->irq, blkif);
123 if (blkif->blk_rings.common.sring) {
124 xenbus_unmap_ring_vfree(dev, blkif->blk_ring_area);
125 blkif->blk_rings.common.sring = NULL;
129 void tap_blkif_kmem_cache_free(blkif_t *blkif)
131 if (!atomic_dec_and_test(&blkif->refcnt))
133 kmem_cache_free(blkif_cachep, blkif);
136 void __init tap_blkif_interface_init(void)
138 blkif_cachep = kmem_cache_create("blktapif_cache", sizeof(blkif_t),