#include <xen/grant_table.h>
#include <xen/events.h>
#include <xen/page.h>
+#include <xen/platform_pci.h>
#include <xen/interface/grant_table.h>
#include <xen/interface/io/blkif.h>
static int xlvbd_barrier(struct blkfront_info *info)
{
int err;
+ const char *barrier;
- err = blk_queue_ordered(info->rq,
- info->feature_barrier ? QUEUE_ORDERED_DRAIN : QUEUE_ORDERED_NONE);
+ switch (info->feature_barrier) {
+ case QUEUE_ORDERED_DRAIN: barrier = "enabled (drain)"; break;
+ case QUEUE_ORDERED_TAG: barrier = "enabled (tag)"; break;
+ case QUEUE_ORDERED_NONE: barrier = "disabled"; break;
+ default: return -EINVAL;
+ }
+
+ err = blk_queue_ordered(info->rq, info->feature_barrier);
if (err)
return err;
printk(KERN_INFO "blkfront: %s: barriers %s\n",
- info->gd->disk_name,
- info->feature_barrier ? "enabled" : "disabled");
+ info->gd->disk_name, barrier);
return 0;
}
info->rq = gd->queue;
info->gd = gd;
- if (info->feature_barrier)
- xlvbd_barrier(info);
+ xlvbd_barrier(info);
if (vdisk_info & VDISK_READONLY)
set_disk_ro(gd, 1);
printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
info->gd->disk_name);
error = -EOPNOTSUPP;
- info->feature_barrier = 0;
+ info->feature_barrier = QUEUE_ORDERED_NONE;
xlvbd_barrier(info);
}
/* fall through */
}
}
+ if (xen_hvm_domain()) {
+ char *type;
+ int len;
+ /* no unplug has been done: do not hook devices != xen vbds */
+ if (xen_platform_pci_unplug & XEN_UNPLUG_IGNORE) {
+ int major;
+
+ if (!VDEV_IS_EXTENDED(vdevice))
+ major = BLKIF_MAJOR(vdevice);
+ else
+ major = XENVBD_MAJOR;
+
+ if (major != XENVBD_MAJOR) {
+ printk(KERN_INFO
+ "%s: HVM does not support vbd %d as xen block device\n",
+ __FUNCTION__, vdevice);
+ return -ENODEV;
+ }
+ }
+ /* do not create a PV cdrom device if we are an HVM guest */
+ type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
+ if (IS_ERR(type))
+ return -ENODEV;
+ if (strncmp(type, "cdrom", 5) == 0) {
+ kfree(type);
+ return -ENODEV;
+ }
+ kfree(type);
+ }
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
unsigned long sector_size;
unsigned int binfo;
int err;
+ int barrier;
switch (info->connected) {
case BLKIF_STATE_CONNECTED:
}
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-barrier", "%lu", &info->feature_barrier,
+ "feature-barrier", "%lu", &barrier,
NULL);
+
+ /*
+ * If there's no "feature-barrier" defined, then it means
+ * we're dealing with a very old backend which writes
+ * synchronously; draining will do what needs to get done.
+ *
+ * If there are barriers, then we can do full queued writes
+ * with tagged barriers.
+ *
+ * If barriers are not supported, then there's no much we can
+ * do, so just set ordering to NONE.
+ */
if (err)
- info->feature_barrier = 0;
+ info->feature_barrier = QUEUE_ORDERED_DRAIN;
+ else if (barrier)
+ info->feature_barrier = QUEUE_ORDERED_TAG;
+ else
+ info->feature_barrier = QUEUE_ORDERED_NONE;
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
kfree(info);
}
+out:
unlock_kernel();
return 0;
}