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/events.h>
35 #include <xen/grant_table.h>
36 #include <linux/kthread.h>
38 static struct kmem_cache *blkif_cachep;
40 blkif_t *blkif_alloc(domid_t domid)
44 blkif = kmem_cache_alloc(blkif_cachep, GFP_KERNEL);
46 return ERR_PTR(-ENOMEM);
48 memset(blkif, 0, sizeof(*blkif));
50 spin_lock_init(&blkif->blk_ring_lock);
51 atomic_set(&blkif->refcnt, 1);
52 init_waitqueue_head(&blkif->wq);
53 blkif->st_print = jiffies;
54 init_waitqueue_head(&blkif->waiting_to_free);
59 static int map_frontend_page(blkif_t *blkif, unsigned long shared_page)
61 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 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
70 DPRINTK(" Grant table operation failure !\n");
74 blkif->shmem_ref = shared_page;
75 blkif->shmem_handle = op.handle;
80 static void unmap_frontend_page(blkif_t *blkif)
82 struct gnttab_unmap_grant_ref op;
84 gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr,
85 GNTMAP_host_map, blkif->shmem_handle);
87 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
91 int blkif_map(blkif_t *blkif, unsigned long shared_page, unsigned int evtchn)
95 /* Already connected through? */
99 if ( (blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE)) == NULL )
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);
138 unmap_frontend_page(blkif);
139 free_vm_area(blkif->blk_ring_area);
140 blkif->blk_rings.common.sring = NULL;
148 void blkif_disconnect(blkif_t *blkif)
150 if (blkif->xenblkd) {
151 kthread_stop(blkif->xenblkd);
152 blkif->xenblkd = NULL;
155 atomic_dec(&blkif->refcnt);
156 wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
157 atomic_inc(&blkif->refcnt);
160 unbind_from_irqhandler(blkif->irq, blkif);
164 if (blkif->blk_rings.common.sring) {
165 unmap_frontend_page(blkif);
166 free_vm_area(blkif->blk_ring_area);
167 blkif->blk_rings.common.sring = NULL;
171 void blkif_free(blkif_t *blkif)
173 if (!atomic_dec_and_test(&blkif->refcnt))
175 kmem_cache_free(blkif_cachep, blkif);
178 int __init blkif_interface_init(void)
180 blkif_cachep = kmem_cache_create("blkif_cache", sizeof(blkif_t),