xen/blkback: Squash vbd.c,interface.c in blkback.c and xenbus.c respectivly.
Daniel Stodden suggested to eliminate vbd.c and interface.c, inlining the
critical bits where they belong, respectively.
Leaving only blkback.c for the data- and xenbus.c for the control path.
Suggested-by: Daniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/block/xen-blkback/Makefile b/drivers/block/xen-blkback/Makefile
index f1ae1ff..e491c1b 100644
--- a/drivers/block/xen-blkback/Makefile
+++ b/drivers/block/xen-blkback/Makefile
@@ -1,3 +1,3 @@
obj-$(CONFIG_XEN_BLKDEV_BACKEND) := xen-blkback.o
-xen-blkback-y := blkback.o xenbus.o interface.o vbd.o
+xen-blkback-y := blkback.o xenbus.o
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 59a2bae..63001fa 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -167,6 +167,141 @@
}
/*
+ * Routines for managing virtual block devices (vbds).
+ */
+
+#define vbd_sz(_v) ((_v)->bdev->bd_part ? \
+ (_v)->bdev->bd_part->nr_sects : \
+ get_capacity((_v)->bdev->bd_disk))
+
+unsigned long long vbd_size(struct vbd *vbd)
+{
+ return vbd_sz(vbd);
+}
+
+unsigned int vbd_info(struct vbd *vbd)
+{
+ return vbd->type | (vbd->readonly ? VDISK_READONLY : 0);
+}
+
+unsigned long vbd_secsize(struct vbd *vbd)
+{
+ return bdev_logical_block_size(vbd->bdev);
+}
+
+int vbd_create(struct blkif_st *blkif, blkif_vdev_t handle, unsigned major,
+ unsigned minor, int readonly, int cdrom)
+{
+ struct vbd *vbd;
+ struct block_device *bdev;
+
+ vbd = &blkif->vbd;
+ vbd->handle = handle;
+ vbd->readonly = readonly;
+ vbd->type = 0;
+
+ vbd->pdevice = MKDEV(major, minor);
+
+ bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ?
+ FMODE_READ : FMODE_WRITE, NULL);
+
+ if (IS_ERR(bdev)) {
+ DPRINTK("vbd_creat: device %08x could not be opened.\n",
+ vbd->pdevice);
+ return -ENOENT;
+ }
+
+ vbd->bdev = bdev;
+ vbd->size = vbd_size(vbd);
+
+ if (vbd->bdev->bd_disk == NULL) {
+ DPRINTK("vbd_creat: device %08x doesn't exist.\n",
+ vbd->pdevice);
+ vbd_free(vbd);
+ return -ENOENT;
+ }
+
+ if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
+ vbd->type |= VDISK_CDROM;
+ if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)
+ vbd->type |= VDISK_REMOVABLE;
+
+ DPRINTK("Successful creation of handle=%04x (dom=%u)\n",
+ handle, blkif->domid);
+ return 0;
+}
+
+void vbd_free(struct vbd *vbd)
+{
+ if (vbd->bdev)
+ blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE);
+ vbd->bdev = NULL;
+}
+
+int vbd_translate(struct phys_req *req, struct blkif_st *blkif, int operation)
+{
+ struct vbd *vbd = &blkif->vbd;
+ int rc = -EACCES;
+
+ if ((operation != READ) && vbd->readonly)
+ goto out;
+
+ if (unlikely((req->sector_number + req->nr_sects) > vbd_sz(vbd)))
+ goto out;
+
+ req->dev = vbd->pdevice;
+ req->bdev = vbd->bdev;
+ rc = 0;
+
+ out:
+ return rc;
+}
+
+void vbd_resize(struct blkif_st *blkif)
+{
+ struct vbd *vbd = &blkif->vbd;
+ struct xenbus_transaction xbt;
+ int err;
+ struct xenbus_device *dev = blkback_xenbus(blkif->be);
+ unsigned long long new_size = vbd_size(vbd);
+
+ printk(KERN_INFO "VBD Resize: Domid: %d, Device: (%d, %d)\n",
+ blkif->domid, MAJOR(vbd->pdevice), MINOR(vbd->pdevice));
+ printk(KERN_INFO "VBD Resize: new size %llu\n", new_size);
+ vbd->size = new_size;
+again:
+ err = xenbus_transaction_start(&xbt);
+ if (err) {
+ printk(KERN_WARNING "Error starting transaction");
+ return;
+ }
+ err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
+ vbd_size(vbd));
+ if (err) {
+ printk(KERN_WARNING "Error writing new size");
+ goto abort;
+ }
+ /*
+ * Write the current state; we will use this to synchronize
+ * the front-end. If the current state is "connected" the
+ * front-end will get the new size information online.
+ */
+ err = xenbus_printf(xbt, dev->nodename, "state", "%d", dev->state);
+ if (err) {
+ printk(KERN_WARNING "Error writing the state");
+ goto abort;
+ }
+
+ err = xenbus_transaction_end(xbt, 0);
+ if (err == -EAGAIN)
+ goto again;
+ if (err)
+ printk(KERN_WARNING "Error ending transaction");
+abort:
+ xenbus_transaction_end(xbt, 1);
+}
+
+/*
* Notification from the guest OS.
*/
static void blkif_notify_work(struct blkif_st *blkif)
diff --git a/drivers/block/xen-blkback/interface.c b/drivers/block/xen-blkback/interface.c
deleted file mode 100644
index 163aed4..0000000
--- a/drivers/block/xen-blkback/interface.c
+++ /dev/null
@@ -1,185 +0,0 @@
-/******************************************************************************
- * 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;
-}
diff --git a/drivers/block/xen-blkback/vbd.c b/drivers/block/xen-blkback/vbd.c
deleted file mode 100644
index d0ff4cf..0000000
--- a/drivers/block/xen-blkback/vbd.c
+++ /dev/null
@@ -1,162 +0,0 @@
-/******************************************************************************
- * Routines for managing virtual block devices (VBDs).
- *
- * Copyright (c) 2003-2005, Keir Fraser & Steve Hand
- *
- * 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"
-
-#define vbd_sz(_v) ((_v)->bdev->bd_part ? \
- (_v)->bdev->bd_part->nr_sects : \
- get_capacity((_v)->bdev->bd_disk))
-
-unsigned long long vbd_size(struct vbd *vbd)
-{
- return vbd_sz(vbd);
-}
-
-unsigned int vbd_info(struct vbd *vbd)
-{
- return vbd->type | (vbd->readonly ? VDISK_READONLY : 0);
-}
-
-unsigned long vbd_secsize(struct vbd *vbd)
-{
- return bdev_logical_block_size(vbd->bdev);
-}
-
-int vbd_create(struct blkif_st *blkif, blkif_vdev_t handle, unsigned major,
- unsigned minor, int readonly, int cdrom)
-{
- struct vbd *vbd;
- struct block_device *bdev;
-
- vbd = &blkif->vbd;
- vbd->handle = handle;
- vbd->readonly = readonly;
- vbd->type = 0;
-
- vbd->pdevice = MKDEV(major, minor);
-
- bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ?
- FMODE_READ : FMODE_WRITE, NULL);
-
- if (IS_ERR(bdev)) {
- DPRINTK("vbd_creat: device %08x could not be opened.\n",
- vbd->pdevice);
- return -ENOENT;
- }
-
- vbd->bdev = bdev;
- vbd->size = vbd_size(vbd);
-
- if (vbd->bdev->bd_disk == NULL) {
- DPRINTK("vbd_creat: device %08x doesn't exist.\n",
- vbd->pdevice);
- vbd_free(vbd);
- return -ENOENT;
- }
-
- if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
- vbd->type |= VDISK_CDROM;
- if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)
- vbd->type |= VDISK_REMOVABLE;
-
- DPRINTK("Successful creation of handle=%04x (dom=%u)\n",
- handle, blkif->domid);
- return 0;
-}
-
-void vbd_free(struct vbd *vbd)
-{
- if (vbd->bdev)
- blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE);
- vbd->bdev = NULL;
-}
-
-int vbd_translate(struct phys_req *req, struct blkif_st *blkif, int operation)
-{
- struct vbd *vbd = &blkif->vbd;
- int rc = -EACCES;
-
- if ((operation != READ) && vbd->readonly)
- goto out;
-
- if (unlikely((req->sector_number + req->nr_sects) > vbd_sz(vbd)))
- goto out;
-
- req->dev = vbd->pdevice;
- req->bdev = vbd->bdev;
- rc = 0;
-
- out:
- return rc;
-}
-
-void vbd_resize(struct blkif_st *blkif)
-{
- struct vbd *vbd = &blkif->vbd;
- struct xenbus_transaction xbt;
- int err;
- struct xenbus_device *dev = blkback_xenbus(blkif->be);
- unsigned long long new_size = vbd_size(vbd);
-
- printk(KERN_INFO "VBD Resize: Domid: %d, Device: (%d, %d)\n",
- blkif->domid, MAJOR(vbd->pdevice), MINOR(vbd->pdevice));
- printk(KERN_INFO "VBD Resize: new size %llu\n", new_size);
- vbd->size = new_size;
-again:
- err = xenbus_transaction_start(&xbt);
- if (err) {
- printk(KERN_WARNING "Error starting transaction");
- return;
- }
- err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
- vbd_size(vbd));
- if (err) {
- printk(KERN_WARNING "Error writing new size");
- goto abort;
- }
- /*
- * Write the current state; we will use this to synchronize
- * the front-end. If the current state is "connected" the
- * front-end will get the new size information online.
- */
- err = xenbus_printf(xbt, dev->nodename, "state", "%d", dev->state);
- if (err) {
- printk(KERN_WARNING "Error writing the state");
- goto abort;
- }
-
- err = xenbus_transaction_end(xbt, 0);
- if (err == -EAGAIN)
- goto again;
- if (err)
- printk(KERN_WARNING "Error ending transaction");
-abort:
- xenbus_transaction_end(xbt, 1);
-}
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index b41ed65d..0c263a2 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -20,6 +20,8 @@
#include <stdarg.h>
#include <linux/module.h>
#include <linux/kthread.h>
+#include <xen/events.h>
+#include <xen/grant_table.h>
#include "common.h"
#undef DPRINTK
@@ -36,6 +38,7 @@
char *mode;
};
+static struct kmem_cache *blkif_cachep;
static void connect(struct backend_info *);
static int connect_ring(struct backend_info *);
static void backend_changed(struct xenbus_watch *, const char **,
@@ -106,6 +109,154 @@
}
}
+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;
+}
/*
* sysfs interface for VBD I/O requests