// SPDX-License-Identifier: GPL-2.0-or-later
/* Xenbus code for blkif backend
Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
Copyright (C) 2005 XenSource Ltd
*/
#define pr_fmt(fmt) "xen-blkback: " fmt
#include <stdarg.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <xen/events.h>
#include <xen/grant_table.h>
#include "common.h"
/* On the XenBus the max length of 'ring-ref%u'. */
#define RINGREF_NAME_LEN (20)
struct backend_info {
struct xenbus_device *dev;
struct xen_blkif *blkif;
struct xenbus_watch backend_watch;
unsigned major;
unsigned minor;
char *mode;
};
static struct kmem_cache *xen_blkif_cachep;
static void connect(struct backend_info *);
static int connect_ring(struct backend_info *);
static void backend_changed(struct xenbus_watch *, const char *,
const char *);
static void xen_blkif_free(struct xen_blkif *blkif);
static void xen_vbd_free(struct xen_vbd *vbd);
struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be)
{
return be->dev;
}
/*
* The last request could free the device from softirq context and
* xen_blkif_free() can sleep.
*/
static void xen_blkif_deferred_free(struct work_struct *work)
{
struct xen_blkif *blkif;
blkif = container_of(work, struct xen_blkif, free_work);
xen_blkif_free(blkif);
}
static int blkback_name(struct xen_blkif *blkif, char *buf)
{
char *devpath, *devname;
struct xenbus_device *dev = blkif->be->dev;
devpath = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL);
if (IS_ERR(devpath))
return PTR_ERR(devpath);
devname = strstr(devpath, "/dev/");
if (devname != NULL)
devname += strlen("/dev/");
else
devname = devpath;
snprintf(buf, TASK_COMM_LEN, "%d.%s", blkif->domid, devname);
kfree(devpath);
return 0;
}
static void xen_update_blkif_status(struct xen_blkif *blkif)
{
int err;
char name[TASK_COMM_LEN];
struct xen_blkif_ring *ring;
int i;
/* Not ready to connect? */
if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev)
return;
/* Already connected? */
if (blkif->be->dev->state == XenbusStateConnected)
return;
/* Attempt to connect: exit if we fail to. */
connect(blkif->be);
if (blkif->be->dev->state != XenbusStateConnected)
return;
err = blkback_name(blkif, name);
if (err) {
xenbus_dev_error(blkif->be->dev, err, "get blkback dev name");
return;
}
err = filemap_write_and_wait(blkif->vbd.bdev->bd_inode->i_mapping);
if (err) {
xenbus_dev_error(blkif->be->dev, err, "block flush");
return;
}
invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping);
for (i = 0; i < blkif->nr_rings; i++) {
ring = &blkif->rings[i];
ring->xenblkd = kthread_run(xen_blkif_schedule, ring