diff options
Diffstat (limited to 'drivers/block/xen-blkback/interface.c')
-rw-r--r-- | drivers/block/xen-blkback/interface.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/drivers/block/xen-blkback/interface.c b/drivers/block/xen-blkback/interface.c new file mode 100644 index 0000000..163aed4 --- /dev/null +++ b/drivers/block/xen-blkback/interface.c @@ -0,0 +1,185 @@ +/****************************************************************************** + * Block-device interface management. + * + * Copyright (c) 2004, Keir Fraser + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation; or, when distributed + * separately from the Linux kernel or incorporated into other + * software packages, subject to the following license: + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this source file (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, + * and to permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + */ + +#include "common.h" +#include <xen/events.h> +#include <xen/grant_table.h> +#include <linux/kthread.h> + +static struct kmem_cache *blkif_cachep; + +struct blkif_st *blkif_alloc(domid_t domid) +{ + struct blkif_st *blkif; + + blkif = kmem_cache_alloc(blkif_cachep, GFP_KERNEL); + if (!blkif) + return ERR_PTR(-ENOMEM); + + memset(blkif, 0, sizeof(*blkif)); + blkif->domid = domid; + spin_lock_init(&blkif->blk_ring_lock); + atomic_set(&blkif->refcnt, 1); + init_waitqueue_head(&blkif->wq); + blkif->st_print = jiffies; + init_waitqueue_head(&blkif->waiting_to_free); + + return blkif; +} + +static int map_frontend_page(struct blkif_st *blkif, unsigned long shared_page) +{ + struct gnttab_map_grant_ref op; + + gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr, + GNTMAP_host_map, shared_page, blkif->domid); + + if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1)) + BUG(); + + if (op.status) { + DPRINTK(" Grant table operation failure !\n"); + return op.status; + } + + blkif->shmem_ref = shared_page; + blkif->shmem_handle = op.handle; + + return 0; +} + +static void unmap_frontend_page(struct blkif_st *blkif) +{ + struct gnttab_unmap_grant_ref op; + + gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr, + GNTMAP_host_map, blkif->shmem_handle); + + if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1)) + BUG(); +} + +int blkif_map(struct blkif_st *blkif, unsigned long shared_page, + unsigned int evtchn) +{ + int err; + + /* Already connected through? */ + if (blkif->irq) + return 0; + + blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE); + if (!blkif->blk_ring_area) + return -ENOMEM; + + err = map_frontend_page(blkif, shared_page); + if (err) { + free_vm_area(blkif->blk_ring_area); + return err; + } + + switch (blkif->blk_protocol) { + case BLKIF_PROTOCOL_NATIVE: + { + struct blkif_sring *sring; + sring = (struct blkif_sring *)blkif->blk_ring_area->addr; + BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE); + break; + } + case BLKIF_PROTOCOL_X86_32: + { + struct blkif_x86_32_sring *sring_x86_32; + sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring_area->addr; + BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE); + break; + } + case BLKIF_PROTOCOL_X86_64: + { + struct blkif_x86_64_sring *sring_x86_64; + sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr; + BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE); + break; + } + default: + BUG(); + } + + err = bind_interdomain_evtchn_to_irqhandler( + blkif->domid, evtchn, blkif_be_int, 0, "blkif-backend", blkif); + if (err < 0) { + unmap_frontend_page(blkif); + free_vm_area(blkif->blk_ring_area); + blkif->blk_rings.common.sring = NULL; + return err; + } + blkif->irq = err; + + return 0; +} + +void blkif_disconnect(struct blkif_st *blkif) +{ + if (blkif->xenblkd) { + kthread_stop(blkif->xenblkd); + blkif->xenblkd = NULL; + } + + atomic_dec(&blkif->refcnt); + wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0); + atomic_inc(&blkif->refcnt); + + if (blkif->irq) { + unbind_from_irqhandler(blkif->irq, blkif); + blkif->irq = 0; + } + + if (blkif->blk_rings.common.sring) { + unmap_frontend_page(blkif); + free_vm_area(blkif->blk_ring_area); + blkif->blk_rings.common.sring = NULL; + } +} + +void blkif_free(struct blkif_st *blkif) +{ + if (!atomic_dec_and_test(&blkif->refcnt)) + BUG(); + kmem_cache_free(blkif_cachep, blkif); +} + +int __init blkif_interface_init(void) +{ + blkif_cachep = kmem_cache_create("blkif_cache", sizeof(struct blkif_st), + 0, 0, NULL); + if (!blkif_cachep) + return -ENOMEM; + + return 0; +} |