diff options
Diffstat (limited to 'drivers/block/xen-blkback')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 22 | ||||
| -rw-r--r-- | drivers/block/xen-blkback/xenbus.c | 27 |
2 files changed, 35 insertions, 14 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index adfc9352351d..501e9dacfff9 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -201,7 +201,7 @@ static inline void shrink_free_pagepool(struct xen_blkif_ring *ring, int num) #define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page))) -static int do_block_io_op(struct xen_blkif_ring *ring); +static int do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags); static int dispatch_rw_block_io(struct xen_blkif_ring *ring, struct blkif_request *req, struct pending_req *pending_req); @@ -612,6 +612,8 @@ int xen_blkif_schedule(void *arg) struct xen_vbd *vbd = &blkif->vbd; unsigned long timeout; int ret; + bool do_eoi; + unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS; set_freezable(); while (!kthread_should_stop()) { @@ -636,16 +638,23 @@ int xen_blkif_schedule(void *arg) if (timeout == 0) goto purge_gnt_list; + do_eoi = ring->waiting_reqs; + ring->waiting_reqs = 0; smp_mb(); /* clear flag *before* checking for work */ - ret = do_block_io_op(ring); + ret = do_block_io_op(ring, &eoi_flags); if (ret > 0) ring->waiting_reqs = 1; if (ret == -EACCES) wait_event_interruptible(ring->shutdown_wq, kthread_should_stop()); + if (do_eoi && !ring->waiting_reqs) { + xen_irq_lateeoi(ring->irq, eoi_flags); + eoi_flags |= XEN_EOI_FLAG_SPURIOUS; + } + purge_gnt_list: if (blkif->vbd.feature_gnt_persistent && time_after(jiffies, ring->next_lru)) { @@ -1121,7 +1130,7 @@ static void end_block_io_op(struct bio *bio) * and transmute it to the block API to hand it over to the proper block disk. */ static int -__do_block_io_op(struct xen_blkif_ring *ring) +__do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags) { union blkif_back_rings *blk_rings = &ring->blk_rings; struct blkif_request req; @@ -1144,6 +1153,9 @@ __do_block_io_op(struct xen_blkif_ring *ring) if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc)) break; + /* We've seen a request, so clear spurious eoi flag. */ + *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS; + if (kthread_should_stop()) { more_to_do = 1; break; @@ -1202,13 +1214,13 @@ done: } static int -do_block_io_op(struct xen_blkif_ring *ring) +do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags) { union blkif_back_rings *blk_rings = &ring->blk_rings; int more_to_do; do { - more_to_do = __do_block_io_op(ring); + more_to_do = __do_block_io_op(ring, eoi_flags); if (more_to_do) break; diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index b9aa5d1ac10b..f5705569e2a7 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -246,9 +246,8 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, if (req_prod - rsp_prod > size) goto fail; - err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, - xen_blkif_be_int, 0, - "blkif-backend", ring); + err = bind_interdomain_evtchn_to_irqhandler_lateeoi(blkif->domid, + evtchn, xen_blkif_be_int, 0, "blkif-backend", ring); if (err < 0) goto fail; ring->irq = err; @@ -474,6 +473,12 @@ static void xen_vbd_free(struct xen_vbd *vbd) vbd->bdev = NULL; } +/* Enable the persistent grants feature. */ +static bool feature_persistent = true; +module_param(feature_persistent, bool, 0644); +MODULE_PARM_DESC(feature_persistent, + "Enables the persistent grants feature"); + static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, unsigned major, unsigned minor, int readonly, int cdrom) @@ -519,6 +524,8 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, if (q && blk_queue_secure_erase(q)) vbd->discard_secure = true; + vbd->feature_gnt_persistent = feature_persistent; + pr_debug("Successful creation of handle=%04x (dom=%u)\n", handle, blkif->domid); return 0; @@ -906,7 +913,8 @@ again: xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); - err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1); + err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", + be->blkif->vbd.feature_gnt_persistent); if (err) { xenbus_dev_fatal(dev, err, "writing %s/feature-persistent", dev->nodename); @@ -1067,7 +1075,6 @@ static int connect_ring(struct backend_info *be) { struct xenbus_device *dev = be->dev; struct xen_blkif *blkif = be->blkif; - unsigned int pers_grants; char protocol[64] = ""; int err, i; char *xspath; @@ -1093,9 +1100,11 @@ static int connect_ring(struct backend_info *be) xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); return -ENOSYS; } - pers_grants = xenbus_read_unsigned(dev->otherend, "feature-persistent", - 0); - blkif->vbd.feature_gnt_persistent = pers_grants; + if (blkif->vbd.feature_gnt_persistent) + blkif->vbd.feature_gnt_persistent = + xenbus_read_unsigned(dev->otherend, + "feature-persistent", 0); + blkif->vbd.overflow_max_grants = 0; /* @@ -1118,7 +1127,7 @@ static int connect_ring(struct backend_info *be) pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename, blkif->nr_rings, blkif->blk_protocol, protocol, - pers_grants ? "persistent grants" : ""); + blkif->vbd.feature_gnt_persistent ? "persistent grants" : ""); ring_page_order = xenbus_read_unsigned(dev->otherend, "ring-page-order", 0); |