--- /dev/null
+/******************************************************************************
+ * drivers/xen/blktap/interface.c
+ *
+ * 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/evtchn.h>
+
+static kmem_cache_t *blkif_cachep;
+
+blkif_t *tap_alloc_blkif(domid_t domid)
+{
+ blkif_t *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(blkif_t *blkif, unsigned long shared_page)
+{
+ struct gnttab_map_grant_ref op;
+ int ret;
+
+ gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr,
+ GNTMAP_host_map, shared_page, blkif->domid);
+
+ lock_vm_area(blkif->blk_ring_area);
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
+ unlock_vm_area(blkif->blk_ring_area);
+ BUG_ON(ret);
+
+ 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(blkif_t *blkif)
+{
+ struct gnttab_unmap_grant_ref op;
+ int ret;
+
+ gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr,
+ GNTMAP_host_map, blkif->shmem_handle);
+
+ lock_vm_area(blkif->blk_ring_area);
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
+ unlock_vm_area(blkif->blk_ring_area);
+ BUG_ON(ret);
+}
+
+int tap_blkif_map(blkif_t *blkif, unsigned long shared_page,
+ unsigned int evtchn)
+{
+ blkif_sring_t *sring;
+ int err;
+ struct evtchn_bind_interdomain bind_interdomain;
+
+ /* Already connected through? */
+ if (blkif->irq)
+ return 0;
+
+ if ( (blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE)) == NULL )
+ return -ENOMEM;
+
+ err = map_frontend_page(blkif, shared_page);
+ if (err) {
+ free_vm_area(blkif->blk_ring_area);
+ return err;
+ }
+
+ bind_interdomain.remote_dom = blkif->domid;
+ bind_interdomain.remote_port = evtchn;
+
+ err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
+ &bind_interdomain);
+ if (err) {
+ unmap_frontend_page(blkif);
+ free_vm_area(blkif->blk_ring_area);
+ return err;
+ }
+
+ blkif->evtchn = bind_interdomain.local_port;
+
+ sring = (blkif_sring_t *)blkif->blk_ring_area->addr;
+ BACK_RING_INIT(&blkif->blk_ring, sring, PAGE_SIZE);
+
+ blkif->irq = bind_evtchn_to_irqhandler(
+ blkif->evtchn, tap_blkif_be_int, 0, "blkif-backend", blkif);
+
+ return 0;
+}
+
+void tap_blkif_free(blkif_t *blkif)
+{
+ atomic_dec(&blkif->refcnt);
+ wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
+
+ /* Already disconnected? */
+ if (blkif->irq)
+ unbind_from_irqhandler(blkif->irq, blkif);
+
+ if (blkif->blk_ring.sring) {
+ unmap_frontend_page(blkif);
+ free_vm_area(blkif->blk_ring_area);
+ }
+
+ kmem_cache_free(blkif_cachep, blkif);
+}
+
+void __init tap_blkif_interface_init(void)
+{
+ blkif_cachep = kmem_cache_create("blktapif_cache", sizeof(blkif_t),
+ 0, 0, NULL, NULL);
+}
git://git.onelab.eu / linux-2.6.git / blobdiff