From 2fb1ef4f1226ea6d6d3481036cabe01a4415b68c Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Fri, 11 Dec 2015 12:08:48 -0500 Subject: [PATCH] xen/blkback: pseudo support for multi hardware queues/rings Preparatory patch for multiple hardware queues (rings). The number of rings is unconditionally set to 1, larger number will be enabled in "xen/blkback: get the number of hardware queues/rings from blkfront". Signed-off-by: Arianna Avanzini Signed-off-by: Bob Liu Signed-off-by: Konrad Rzeszutek Wilk --- v2: Align variables in the structures. --- drivers/block/xen-blkback/common.h | 3 +- drivers/block/xen-blkback/xenbus.c | 277 ++++++++++++++++++----------- 2 files changed, 175 insertions(+), 105 deletions(-) diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index dbdf4164c83f..310eff3cf43f 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -340,7 +340,8 @@ struct xen_blkif { struct work_struct free_work; unsigned int nr_ring_pages; /* All rings for this device. */ - struct xen_blkif_ring ring; + struct xen_blkif_ring *rings; + unsigned int nr_rings; }; struct seg_buf { diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index e4bfc928035d..f5bfedd0e948 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -86,9 +86,11 @@ static void xen_update_blkif_status(struct xen_blkif *blkif) { int err; char name[BLKBACK_NAME_LEN]; + struct xen_blkif_ring *ring; + int i; /* Not ready to connect? */ - if (!blkif->ring.irq || !blkif->vbd.bdev) + if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev) return; /* Already connected? */ @@ -113,19 +115,55 @@ static void xen_update_blkif_status(struct xen_blkif *blkif) } invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping); - blkif->ring.xenblkd = kthread_run(xen_blkif_schedule, &blkif->ring, "%s", name); - if (IS_ERR(blkif->ring.xenblkd)) { - err = PTR_ERR(blkif->ring.xenblkd); - blkif->ring.xenblkd = NULL; - xenbus_dev_error(blkif->be->dev, err, "start xenblkd"); - return; + for (i = 0; i < blkif->nr_rings; i++) { + ring = &blkif->rings[i]; + ring->xenblkd = kthread_run(xen_blkif_schedule, ring, "%s-%d", name, i); + if (IS_ERR(ring->xenblkd)) { + err = PTR_ERR(ring->xenblkd); + ring->xenblkd = NULL; + xenbus_dev_fatal(blkif->be->dev, err, + "start %s-%d xenblkd", name, i); + goto out; + } + } + return; + +out: + while (--i >= 0) { + ring = &blkif->rings[i]; + kthread_stop(ring->xenblkd); } + return; +} + +static int xen_blkif_alloc_rings(struct xen_blkif *blkif) +{ + unsigned int r; + + blkif->rings = kzalloc(blkif->nr_rings * sizeof(struct xen_blkif_ring), GFP_KERNEL); + if (!blkif->rings) + return -ENOMEM; + + for (r = 0; r < blkif->nr_rings; r++) { + struct xen_blkif_ring *ring = &blkif->rings[r]; + + spin_lock_init(&ring->blk_ring_lock); + init_waitqueue_head(&ring->wq); + INIT_LIST_HEAD(&ring->pending_free); + + spin_lock_init(&ring->pending_free_lock); + init_waitqueue_head(&ring->pending_free_wq); + init_waitqueue_head(&ring->shutdown_wq); + ring->blkif = blkif; + xen_blkif_get(blkif); + } + + return 0; } static struct xen_blkif *xen_blkif_alloc(domid_t domid) { struct xen_blkif *blkif; - struct xen_blkif_ring *ring; BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); @@ -143,15 +181,11 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid) blkif->st_print = jiffies; INIT_WORK(&blkif->persistent_purge_work, xen_blkbk_unmap_purged_grants); - ring = &blkif->ring; - ring->blkif = blkif; - spin_lock_init(&ring->blk_ring_lock); - init_waitqueue_head(&ring->wq); - - INIT_LIST_HEAD(&ring->pending_free); - spin_lock_init(&ring->pending_free_lock); - init_waitqueue_head(&ring->pending_free_wq); - init_waitqueue_head(&ring->shutdown_wq); + blkif->nr_rings = 1; + if (xen_blkif_alloc_rings(blkif)) { + kmem_cache_free(xen_blkif_cachep, blkif); + return ERR_PTR(-ENOMEM); + } return blkif; } @@ -216,50 +250,54 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, static int xen_blkif_disconnect(struct xen_blkif *blkif) { struct pending_req *req, *n; - int i = 0, j; - struct xen_blkif_ring *ring = &blkif->ring; + unsigned int j, r; - if (ring->xenblkd) { - kthread_stop(ring->xenblkd); - wake_up(&ring->shutdown_wq); - ring->xenblkd = NULL; - } + for (r = 0; r < blkif->nr_rings; r++) { + struct xen_blkif_ring *ring = &blkif->rings[r]; + unsigned int i = 0; - /* The above kthread_stop() guarantees that at this point we - * don't have any discard_io or other_io requests. So, checking - * for inflight IO is enough. - */ - if (atomic_read(&ring->inflight) > 0) - return -EBUSY; + if (ring->xenblkd) { + kthread_stop(ring->xenblkd); + wake_up(&ring->shutdown_wq); + ring->xenblkd = NULL; + } - if (ring->irq) { - unbind_from_irqhandler(ring->irq, ring); - ring->irq = 0; - } + /* The above kthread_stop() guarantees that at this point we + * don't have any discard_io or other_io requests. So, checking + * for inflight IO is enough. + */ + if (atomic_read(&ring->inflight) > 0) + return -EBUSY; - if (ring->blk_rings.common.sring) { - xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); - ring->blk_rings.common.sring = NULL; - } + if (ring->irq) { + unbind_from_irqhandler(ring->irq, ring); + ring->irq = 0; + } - /* Remove all persistent grants and the cache of ballooned pages. */ - xen_blkbk_free_caches(ring); + if (ring->blk_rings.common.sring) { + xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); + ring->blk_rings.common.sring = NULL; + } - /* Check that there is no request in use */ - list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { - list_del(&req->free_list); + /* Remove all persistent grants and the cache of ballooned pages. */ + xen_blkbk_free_caches(ring); - for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) - kfree(req->segments[j]); + /* Check that there is no request in use */ + list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { + list_del(&req->free_list); - for (j = 0; j < MAX_INDIRECT_PAGES; j++) - kfree(req->indirect_pages[j]); + for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) + kfree(req->segments[j]); - kfree(req); - i++; - } + for (j = 0; j < MAX_INDIRECT_PAGES; j++) + kfree(req->indirect_pages[j]); - WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages)); + kfree(req); + i++; + } + + WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages)); + } blkif->nr_ring_pages = 0; return 0; @@ -279,6 +317,7 @@ static void xen_blkif_free(struct xen_blkif *blkif) BUG_ON(!list_empty(&blkif->free_pages)); BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts)); + kfree(blkif->rings); kmem_cache_free(xen_blkif_cachep, blkif); } @@ -427,6 +466,7 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, static int xen_blkbk_remove(struct xenbus_device *dev) { struct backend_info *be = dev_get_drvdata(&dev->dev); + unsigned int i; pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id); @@ -443,7 +483,8 @@ static int xen_blkbk_remove(struct xenbus_device *dev) if (be->blkif) { xen_blkif_disconnect(be->blkif); - xen_blkif_put(be->blkif); + for (i = 0; i < be->blkif->nr_rings; i++) + xen_blkif_put(be->blkif); } kfree(be->mode); @@ -826,51 +867,43 @@ again: xenbus_transaction_end(xbt, 1); } - -static int connect_ring(struct backend_info *be) +/* + * Each ring may have multi pages, depends on "ring-page-order". + */ +static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir) { - struct xenbus_device *dev = be->dev; unsigned int ring_ref[XENBUS_MAX_RING_GRANTS]; - unsigned int evtchn, nr_grefs, ring_page_order; - unsigned int pers_grants; - char protocol[64] = ""; struct pending_req *req, *n; int err, i, j; - struct xen_blkif_ring *ring = &be->blkif->ring; - - pr_debug("%s %s\n", __func__, dev->otherend); + struct xen_blkif *blkif = ring->blkif; + struct xenbus_device *dev = blkif->be->dev; + unsigned int ring_page_order, nr_grefs, evtchn; - err = xenbus_scanf(XBT_NIL, dev->otherend, "event-channel", "%u", + err = xenbus_scanf(XBT_NIL, dir, "event-channel", "%u", &evtchn); if (err != 1) { err = -EINVAL; - xenbus_dev_fatal(dev, err, "reading %s/event-channel", - dev->otherend); + xenbus_dev_fatal(dev, err, "reading %s/event-channel", dir); return err; } - pr_info("event-channel %u\n", evtchn); err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u", &ring_page_order); if (err != 1) { - err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", - "%u", &ring_ref[0]); + err = xenbus_scanf(XBT_NIL, dir, "ring-ref", "%u", &ring_ref[0]); if (err != 1) { err = -EINVAL; - xenbus_dev_fatal(dev, err, "reading %s/ring-ref", - dev->otherend); + xenbus_dev_fatal(dev, err, "reading %s/ring-ref", dir); return err; } nr_grefs = 1; - pr_info("%s:using single page: ring-ref %d\n", dev->otherend, - ring_ref[0]); } else { unsigned int i; if (ring_page_order > xen_blkif_max_ring_order) { err = -EINVAL; xenbus_dev_fatal(dev, err, "%s/request %d ring page order exceed max:%d", - dev->otherend, ring_page_order, + dir, ring_page_order, xen_blkif_max_ring_order); return err; } @@ -880,46 +913,17 @@ static int connect_ring(struct backend_info *be) char ring_ref_name[RINGREF_NAME_LEN]; snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); - err = xenbus_scanf(XBT_NIL, dev->otherend, ring_ref_name, + err = xenbus_scanf(XBT_NIL, dir, ring_ref_name, "%u", &ring_ref[i]); if (err != 1) { err = -EINVAL; xenbus_dev_fatal(dev, err, "reading %s/%s", - dev->otherend, ring_ref_name); + dir, ring_ref_name); return err; } - pr_info("ring-ref%u: %u\n", i, ring_ref[i]); } } - - be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT; - err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", - "%63s", protocol, NULL); - if (err) - strcpy(protocol, "unspecified, assuming default"); - else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) - be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; - else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) - be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; - else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) - be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; - else { - xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); - return -1; - } - err = xenbus_gather(XBT_NIL, dev->otherend, - "feature-persistent", "%u", - &pers_grants, NULL); - if (err) - pers_grants = 0; - - be->blkif->vbd.feature_gnt_persistent = pers_grants; - be->blkif->vbd.overflow_max_grants = 0; - be->blkif->nr_ring_pages = nr_grefs; - - pr_info("ring-pages:%d, event-channel %d, protocol %d (%s) %s\n", - nr_grefs, evtchn, be->blkif->blk_protocol, protocol, - pers_grants ? "persistent grants" : ""); + blkif->nr_ring_pages = nr_grefs; for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) { req = kzalloc(sizeof(*req), GFP_KERNEL); @@ -964,6 +968,71 @@ fail: kfree(req); } return -ENOMEM; + +} + +static int connect_ring(struct backend_info *be) +{ + struct xenbus_device *dev = be->dev; + unsigned int pers_grants; + char protocol[64] = ""; + int err, i; + char *xspath; + size_t xspathsize; + const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */ + + pr_debug("%s %s\n", __func__, dev->otherend); + + be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT; + err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", + "%63s", protocol, NULL); + if (err) + strcpy(protocol, "unspecified, assuming default"); + else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) + be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; + else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) + be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; + else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) + be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; + else { + xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); + return -1; + } + err = xenbus_gather(XBT_NIL, dev->otherend, + "feature-persistent", "%u", + &pers_grants, NULL); + if (err) + pers_grants = 0; + + be->blkif->vbd.feature_gnt_persistent = pers_grants; + be->blkif->vbd.overflow_max_grants = 0; + + pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename, + be->blkif->nr_rings, be->blkif->blk_protocol, protocol, + pers_grants ? "persistent grants" : ""); + + if (be->blkif->nr_rings == 1) + return read_per_ring_refs(&be->blkif->rings[0], dev->otherend); + else { + xspathsize = strlen(dev->otherend) + xenstore_path_ext_size; + xspath = kmalloc(xspathsize, GFP_KERNEL); + if (!xspath) { + xenbus_dev_fatal(dev, -ENOMEM, "reading ring references"); + return -ENOMEM; + } + + for (i = 0; i < be->blkif->nr_rings; i++) { + memset(xspath, 0, xspathsize); + snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend, i); + err = read_per_ring_refs(&be->blkif->rings[i], xspath); + if (err) { + kfree(xspath); + return err; + } + } + kfree(xspath); + } + return 0; } static const struct xenbus_device_id xen_blkbk_ids[] = { -- 2.20.1