#include <linux/cdrom.h>
#include <linux/module.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/scatterlist.h>
#include <xen/xen.h>
struct blk_shadow {
struct blkif_request req;
- unsigned long request;
+ struct request *request;
unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
+static DEFINE_MUTEX(blkfront_mutex);
static const struct block_device_operations xlvbd_block_fops;
-#define BLK_RING_SIZE __RING_SIZE((struct blkif_sring *)0, PAGE_SIZE)
+#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
/*
* We have one of these per vbd, whether ide, scsi or 'other'. They
struct gnttab_free_callback callback;
struct blk_shadow shadow[BLK_RING_SIZE];
unsigned long shadow_free;
- int feature_barrier;
+ unsigned int feature_flush;
int is_ready;
};
unsigned long id)
{
info->shadow[id].req.id = info->shadow_free;
- info->shadow[id].request = 0;
+ info->shadow[id].request = NULL;
info->shadow_free = id;
}
}
/*
- * blkif_queue_request
+ * Generate a Xen blkfront IO request from a blk layer request. Reads
+ * and writes are handled as expected. Since we lack a loose flush
+ * request, we map flushes into a full ordered barrier.
*
- * request block io
- *
- * id: for guest use only.
- * operation: BLKIF_OP_{READ,WRITE,PROBE}
- * buffer: buffer to read/write into. this should be a
- * virtual address in the guest os.
+ * @req: a request struct
*/
static int blkif_queue_request(struct request *req)
{
/* Fill out a communications ring structure. */
ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
id = get_id_from_freelist(info);
- info->shadow[id].request = (unsigned long)req;
+ info->shadow[id].request = req;
ring_req->id = id;
ring_req->sector_number = (blkif_sector_t)blk_rq_pos(req);
ring_req->operation = rq_data_dir(req) ?
BLKIF_OP_WRITE : BLKIF_OP_READ;
- if (req->cmd_flags & REQ_HARDBARRIER)
+
+ if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
+ /*
+ * Ideally we could just do an unordered
+ * flush-to-disk, but all we have is a full write
+ * barrier at the moment. However, a barrier write is
+ * a superset of FUA, so we can implement it the same
+ * way. (It's also a FLUSH+FUA, since it is
+ * guaranteed ordered WRT previous writes.)
+ */
ring_req->operation = BLKIF_OP_WRITE_BARRIER;
+ }
ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
}
-static int xlvbd_barrier(struct blkfront_info *info)
+static void xlvbd_flush(struct blkfront_info *info)
{
- int err;
- const char *barrier;
-
- 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;
-
+ blk_queue_flush(info->rq, info->feature_flush);
printk(KERN_INFO "blkfront: %s: barriers %s\n",
- info->gd->disk_name, barrier);
- return 0;
+ info->gd->disk_name,
+ info->feature_flush ? "enabled" : "disabled");
}
info->rq = gd->queue;
info->gd = gd;
- xlvbd_barrier(info);
+ xlvbd_flush(info);
if (vdisk_info & VDISK_READONLY)
set_disk_ro(gd, 1);
bret = RING_GET_RESPONSE(&info->ring, i);
id = bret->id;
- req = (struct request *)info->shadow[id].request;
+ req = info->shadow[id].request;
blkif_completion(&info->shadow[id]);
printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
info->gd->disk_name);
error = -EOPNOTSUPP;
- info->feature_barrier = QUEUE_ORDERED_NONE;
- xlvbd_barrier(info);
+ }
+ if (unlikely(bret->status == BLKIF_RSP_ERROR &&
+ info->shadow[id].req.nr_segments == 0)) {
+ printk(KERN_WARNING "blkfront: %s: empty write barrier op failed\n",
+ info->gd->disk_name);
+ error = -EOPNOTSUPP;
+ }
+ if (unlikely(error)) {
+ if (error == -EOPNOTSUPP)
+ error = 0;
+ info->feature_flush = 0;
+ xlvbd_flush(info);
}
/* fall through */
case BLKIF_OP_READ:
/* Stage 3: Find pending requests and requeue them. */
for (i = 0; i < BLK_RING_SIZE; i++) {
/* Not in use? */
- if (copy[i].request == 0)
+ if (!copy[i].request)
continue;
/* Grab a request slot and copy shadow state into it. */
req->seg[j].gref,
info->xbdev->otherend_id,
pfn_to_mfn(info->shadow[req->id].frame[j]),
- rq_data_dir(
- (struct request *)
- info->shadow[req->id].request));
+ rq_data_dir(info->shadow[req->id].request));
info->shadow[req->id].req = *req;
info->ring.req_prod_pvt++;
/*
* 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.
+ * synchronously; nothing to do.
*
- * If barriers are not supported, then there's no much we can
- * do, so just set ordering to NONE.
+ * If there are barriers, then we use flush.
*/
- if (err)
- info->feature_barrier = QUEUE_ORDERED_DRAIN;
- else if (barrier)
- info->feature_barrier = QUEUE_ORDERED_TAG;
- else
- info->feature_barrier = QUEUE_ORDERED_NONE;
+ info->feature_flush = 0;
+
+ if (!err && barrier)
+ info->feature_flush = REQ_FLUSH | REQ_FUA;
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
case XenbusStateInitialising:
case XenbusStateInitWait:
case XenbusStateInitialised:
+ case XenbusStateReconfiguring:
+ case XenbusStateReconfigured:
case XenbusStateUnknown:
case XenbusStateClosed:
break;
struct blkfront_info *info;
int err = 0;
- lock_kernel();
+ mutex_lock(&blkfront_mutex);
info = disk->private_data;
if (!info) {
mutex_unlock(&info->mutex);
out:
- unlock_kernel();
+ mutex_unlock(&blkfront_mutex);
return err;
}
struct block_device *bdev;
struct xenbus_device *xbdev;
- lock_kernel();
+ mutex_lock(&blkfront_mutex);
bdev = bdget_disk(disk, 0);
bdput(bdev);
}
out:
- unlock_kernel();
+ mutex_unlock(&blkfront_mutex);
return 0;
}
projects / mv-sheeva.git / blobdiff