From 597957000ab5b1b38085c20868f3f7b9c305bae5 Mon Sep 17 00:00:00 2001 From: Bob Liu Date: Sat, 14 Nov 2015 11:12:15 +0800 Subject: [PATCH] xen/blkback: separate ring information out of struct xen_blkif Split per ring information to an new structure "xen_blkif_ring", so that one vbd device can be associated with one or more rings/hardware queues. Introduce 'pers_gnts_lock' to protect the pool of persistent grants since we may have multi backend threads. This patch is a preparation for supporting multi hardware queues/rings. Signed-off-by: Arianna Avanzini Signed-off-by: Bob Liu Signed-off-by: Konrad Rzeszutek Wilk --- v2: Align the variables in the structure. --- drivers/block/xen-blkback/blkback.c | 235 ++++++++++++++++------------ drivers/block/xen-blkback/common.h | 56 ++++--- drivers/block/xen-blkback/xenbus.c | 96 ++++++------ 3 files changed, 215 insertions(+), 172 deletions(-) diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index f9099940c272..4fd8640d146c 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -173,11 +173,11 @@ static inline void shrink_free_pagepool(struct xen_blkif *blkif, int num) #define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page))) -static int do_block_io_op(struct xen_blkif *blkif); -static int dispatch_rw_block_io(struct xen_blkif *blkif, +static int do_block_io_op(struct xen_blkif_ring *ring); +static int dispatch_rw_block_io(struct xen_blkif_ring *ring, struct blkif_request *req, struct pending_req *pending_req); -static void make_response(struct xen_blkif *blkif, u64 id, +static void make_response(struct xen_blkif_ring *ring, u64 id, unsigned short op, int st); #define foreach_grant_safe(pos, n, rbtree, node) \ @@ -189,14 +189,8 @@ static void make_response(struct xen_blkif *blkif, u64 id, /* - * We don't need locking around the persistent grant helpers - * because blkback uses a single-thread for each backed, so we - * can be sure that this functions will never be called recursively. - * - * The only exception to that is put_persistent_grant, that can be called - * from interrupt context (by xen_blkbk_unmap), so we have to use atomic - * bit operations to modify the flags of a persistent grant and to count - * the number of used grants. + * pers_gnts_lock must be used around all the persistent grant helpers + * because blkback may use multi-thread/queue for each backend. */ static int add_persistent_gnt(struct xen_blkif *blkif, struct persistent_gnt *persistent_gnt) @@ -204,6 +198,7 @@ static int add_persistent_gnt(struct xen_blkif *blkif, struct rb_node **new = NULL, *parent = NULL; struct persistent_gnt *this; + BUG_ON(!spin_is_locked(&blkif->pers_gnts_lock)); if (blkif->persistent_gnt_c >= xen_blkif_max_pgrants) { if (!blkif->vbd.overflow_max_grants) blkif->vbd.overflow_max_grants = 1; @@ -241,6 +236,7 @@ static struct persistent_gnt *get_persistent_gnt(struct xen_blkif *blkif, struct persistent_gnt *data; struct rb_node *node = NULL; + BUG_ON(!spin_is_locked(&blkif->pers_gnts_lock)); node = blkif->persistent_gnts.rb_node; while (node) { data = container_of(node, struct persistent_gnt, node); @@ -265,6 +261,7 @@ static struct persistent_gnt *get_persistent_gnt(struct xen_blkif *blkif, static void put_persistent_gnt(struct xen_blkif *blkif, struct persistent_gnt *persistent_gnt) { + BUG_ON(!spin_is_locked(&blkif->pers_gnts_lock)); if(!test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags)) pr_alert_ratelimited("freeing a grant already unused\n"); set_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags); @@ -286,6 +283,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root, unmap_data.unmap_ops = unmap; unmap_data.kunmap_ops = NULL; + BUG_ON(!spin_is_locked(&blkif->pers_gnts_lock)); foreach_grant_safe(persistent_gnt, n, root, node) { BUG_ON(persistent_gnt->handle == BLKBACK_INVALID_HANDLE); @@ -322,11 +320,13 @@ void xen_blkbk_unmap_purged_grants(struct work_struct *work) int segs_to_unmap = 0; struct xen_blkif *blkif = container_of(work, typeof(*blkif), persistent_purge_work); struct gntab_unmap_queue_data unmap_data; + unsigned long flags; unmap_data.pages = pages; unmap_data.unmap_ops = unmap; unmap_data.kunmap_ops = NULL; + spin_lock_irqsave(&blkif->pers_gnts_lock, flags); while(!list_empty(&blkif->persistent_purge_list)) { persistent_gnt = list_first_entry(&blkif->persistent_purge_list, struct persistent_gnt, @@ -348,6 +348,7 @@ void xen_blkbk_unmap_purged_grants(struct work_struct *work) } kfree(persistent_gnt); } + spin_unlock_irqrestore(&blkif->pers_gnts_lock, flags); if (segs_to_unmap > 0) { unmap_data.count = segs_to_unmap; BUG_ON(gnttab_unmap_refs_sync(&unmap_data)); @@ -362,16 +363,18 @@ static void purge_persistent_gnt(struct xen_blkif *blkif) unsigned int num_clean, total; bool scan_used = false, clean_used = false; struct rb_root *root; + unsigned long flags; + spin_lock_irqsave(&blkif->pers_gnts_lock, flags); if (blkif->persistent_gnt_c < xen_blkif_max_pgrants || (blkif->persistent_gnt_c == xen_blkif_max_pgrants && !blkif->vbd.overflow_max_grants)) { - return; + goto out; } if (work_busy(&blkif->persistent_purge_work)) { pr_alert_ratelimited("Scheduled work from previous purge is still busy, cannot purge list\n"); - return; + goto out; } num_clean = (xen_blkif_max_pgrants / 100) * LRU_PERCENT_CLEAN; @@ -379,7 +382,7 @@ static void purge_persistent_gnt(struct xen_blkif *blkif) num_clean = min(blkif->persistent_gnt_c, num_clean); if ((num_clean == 0) || (num_clean > (blkif->persistent_gnt_c - atomic_read(&blkif->persistent_gnt_in_use)))) - return; + goto out; /* * At this point, we can assure that there will be no calls @@ -436,29 +439,35 @@ finished: } blkif->persistent_gnt_c -= (total - num_clean); + spin_unlock_irqrestore(&blkif->pers_gnts_lock, flags); blkif->vbd.overflow_max_grants = 0; /* We can defer this work */ schedule_work(&blkif->persistent_purge_work); pr_debug("Purged %u/%u\n", (total - num_clean), total); return; + +out: + spin_unlock_irqrestore(&blkif->pers_gnts_lock, flags); + + return; } /* * Retrieve from the 'pending_reqs' a free pending_req structure to be used. */ -static struct pending_req *alloc_req(struct xen_blkif *blkif) +static struct pending_req *alloc_req(struct xen_blkif_ring *ring) { struct pending_req *req = NULL; unsigned long flags; - spin_lock_irqsave(&blkif->pending_free_lock, flags); - if (!list_empty(&blkif->pending_free)) { - req = list_entry(blkif->pending_free.next, struct pending_req, + spin_lock_irqsave(&ring->pending_free_lock, flags); + if (!list_empty(&ring->pending_free)) { + req = list_entry(ring->pending_free.next, struct pending_req, free_list); list_del(&req->free_list); } - spin_unlock_irqrestore(&blkif->pending_free_lock, flags); + spin_unlock_irqrestore(&ring->pending_free_lock, flags); return req; } @@ -466,17 +475,17 @@ static struct pending_req *alloc_req(struct xen_blkif *blkif) * Return the 'pending_req' structure back to the freepool. We also * wake up the thread if it was waiting for a free page. */ -static void free_req(struct xen_blkif *blkif, struct pending_req *req) +static void free_req(struct xen_blkif_ring *ring, struct pending_req *req) { unsigned long flags; int was_empty; - spin_lock_irqsave(&blkif->pending_free_lock, flags); - was_empty = list_empty(&blkif->pending_free); - list_add(&req->free_list, &blkif->pending_free); - spin_unlock_irqrestore(&blkif->pending_free_lock, flags); + spin_lock_irqsave(&ring->pending_free_lock, flags); + was_empty = list_empty(&ring->pending_free); + list_add(&req->free_list, &ring->pending_free); + spin_unlock_irqrestore(&ring->pending_free_lock, flags); if (was_empty) - wake_up(&blkif->pending_free_wq); + wake_up(&ring->pending_free_wq); } /* @@ -556,10 +565,10 @@ abort: /* * Notification from the guest OS. */ -static void blkif_notify_work(struct xen_blkif *blkif) +static void blkif_notify_work(struct xen_blkif_ring *ring) { - blkif->waiting_reqs = 1; - wake_up(&blkif->wq); + ring->waiting_reqs = 1; + wake_up(&ring->wq); } irqreturn_t xen_blkif_be_int(int irq, void *dev_id) @@ -590,7 +599,8 @@ static void print_stats(struct xen_blkif *blkif) int xen_blkif_schedule(void *arg) { - struct xen_blkif *blkif = arg; + struct xen_blkif_ring *ring = arg; + struct xen_blkif *blkif = ring->blkif; struct xen_vbd *vbd = &blkif->vbd; unsigned long timeout; int ret; @@ -606,27 +616,27 @@ int xen_blkif_schedule(void *arg) timeout = msecs_to_jiffies(LRU_INTERVAL); timeout = wait_event_interruptible_timeout( - blkif->wq, - blkif->waiting_reqs || kthread_should_stop(), + ring->wq, + ring->waiting_reqs || kthread_should_stop(), timeout); if (timeout == 0) goto purge_gnt_list; timeout = wait_event_interruptible_timeout( - blkif->pending_free_wq, - !list_empty(&blkif->pending_free) || + ring->pending_free_wq, + !list_empty(&ring->pending_free) || kthread_should_stop(), timeout); if (timeout == 0) goto purge_gnt_list; - blkif->waiting_reqs = 0; + ring->waiting_reqs = 0; smp_mb(); /* clear flag *before* checking for work */ - ret = do_block_io_op(blkif); + ret = do_block_io_op(ring); if (ret > 0) - blkif->waiting_reqs = 1; + ring->waiting_reqs = 1; if (ret == -EACCES) - wait_event_interruptible(blkif->shutdown_wq, + wait_event_interruptible(ring->shutdown_wq, kthread_should_stop()); purge_gnt_list: @@ -649,7 +659,7 @@ purge_gnt_list: if (log_stats) print_stats(blkif); - blkif->xenblkd = NULL; + ring->xenblkd = NULL; xen_blkif_put(blkif); return 0; @@ -658,32 +668,40 @@ purge_gnt_list: /* * Remove persistent grants and empty the pool of free pages */ -void xen_blkbk_free_caches(struct xen_blkif *blkif) +void xen_blkbk_free_caches(struct xen_blkif_ring *ring) { + struct xen_blkif *blkif = ring->blkif; + unsigned long flags; + /* Free all persistent grant pages */ + spin_lock_irqsave(&blkif->pers_gnts_lock, flags); if (!RB_EMPTY_ROOT(&blkif->persistent_gnts)) free_persistent_gnts(blkif, &blkif->persistent_gnts, blkif->persistent_gnt_c); BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts)); blkif->persistent_gnt_c = 0; + spin_unlock_irqrestore(&blkif->pers_gnts_lock, flags); /* Since we are shutting down remove all pages from the buffer */ shrink_free_pagepool(blkif, 0 /* All */); } static unsigned int xen_blkbk_unmap_prepare( - struct xen_blkif *blkif, + struct xen_blkif_ring *ring, struct grant_page **pages, unsigned int num, struct gnttab_unmap_grant_ref *unmap_ops, struct page **unmap_pages) { unsigned int i, invcount = 0; + unsigned long flags; for (i = 0; i < num; i++) { if (pages[i]->persistent_gnt != NULL) { - put_persistent_gnt(blkif, pages[i]->persistent_gnt); + spin_lock_irqsave(&ring->blkif->pers_gnts_lock, flags); + put_persistent_gnt(ring->blkif, pages[i]->persistent_gnt); + spin_unlock_irqrestore(&ring->blkif->pers_gnts_lock, flags); continue; } if (pages[i]->handle == BLKBACK_INVALID_HANDLE) @@ -700,17 +718,18 @@ static unsigned int xen_blkbk_unmap_prepare( static void xen_blkbk_unmap_and_respond_callback(int result, struct gntab_unmap_queue_data *data) { - struct pending_req* pending_req = (struct pending_req*) (data->data); - struct xen_blkif *blkif = pending_req->blkif; + struct pending_req *pending_req = (struct pending_req *)(data->data); + struct xen_blkif_ring *ring = pending_req->ring; + struct xen_blkif *blkif = ring->blkif; /* BUG_ON used to reproduce existing behaviour, but is this the best way to deal with this? */ BUG_ON(result); put_free_pages(blkif, data->pages, data->count); - make_response(blkif, pending_req->id, + make_response(ring, pending_req->id, pending_req->operation, pending_req->status); - free_req(blkif, pending_req); + free_req(ring, pending_req); /* * Make sure the request is freed before releasing blkif, * or there could be a race between free_req and the @@ -723,7 +742,7 @@ static void xen_blkbk_unmap_and_respond_callback(int result, struct gntab_unmap_ * pending_free_wq if there's a drain going on, but it has * to be taken into account if the current model is changed. */ - if (atomic_dec_and_test(&blkif->inflight) && atomic_read(&blkif->drain)) { + if (atomic_dec_and_test(&ring->inflight) && atomic_read(&blkif->drain)) { complete(&blkif->drain_complete); } xen_blkif_put(blkif); @@ -732,11 +751,11 @@ static void xen_blkbk_unmap_and_respond_callback(int result, struct gntab_unmap_ static void xen_blkbk_unmap_and_respond(struct pending_req *req) { struct gntab_unmap_queue_data* work = &req->gnttab_unmap_data; - struct xen_blkif *blkif = req->blkif; + struct xen_blkif_ring *ring = req->ring; struct grant_page **pages = req->segments; unsigned int invcount; - invcount = xen_blkbk_unmap_prepare(blkif, pages, req->nr_segs, + invcount = xen_blkbk_unmap_prepare(ring, pages, req->nr_segs, req->unmap, req->unmap_pages); work->data = req; @@ -757,7 +776,7 @@ static void xen_blkbk_unmap_and_respond(struct pending_req *req) * of hypercalls, but since this is only used in error paths there's * no real need. */ -static void xen_blkbk_unmap(struct xen_blkif *blkif, +static void xen_blkbk_unmap(struct xen_blkif_ring *ring, struct grant_page *pages[], int num) { @@ -768,20 +787,20 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif, while (num) { unsigned int batch = min(num, BLKIF_MAX_SEGMENTS_PER_REQUEST); - - invcount = xen_blkbk_unmap_prepare(blkif, pages, batch, + + invcount = xen_blkbk_unmap_prepare(ring, pages, batch, unmap, unmap_pages); if (invcount) { ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount); BUG_ON(ret); - put_free_pages(blkif, unmap_pages, invcount); + put_free_pages(ring->blkif, unmap_pages, invcount); } pages += batch; num -= batch; } } -static int xen_blkbk_map(struct xen_blkif *blkif, +static int xen_blkbk_map(struct xen_blkif_ring *ring, struct grant_page *pages[], int num, bool ro) { @@ -794,6 +813,8 @@ static int xen_blkbk_map(struct xen_blkif *blkif, int ret = 0; int last_map = 0, map_until = 0; int use_persistent_gnts; + struct xen_blkif *blkif = ring->blkif; + unsigned long irq_flags; use_persistent_gnts = (blkif->vbd.feature_gnt_persistent); @@ -806,10 +827,13 @@ again: for (i = map_until; i < num; i++) { uint32_t flags; - if (use_persistent_gnts) + if (use_persistent_gnts) { + spin_lock_irqsave(&blkif->pers_gnts_lock, irq_flags); persistent_gnt = get_persistent_gnt( blkif, pages[i]->gref); + spin_unlock_irqrestore(&blkif->pers_gnts_lock, irq_flags); + } if (persistent_gnt) { /* @@ -880,8 +904,10 @@ again: persistent_gnt->gnt = map[new_map_idx].ref; persistent_gnt->handle = map[new_map_idx].handle; persistent_gnt->page = pages[seg_idx]->page; + spin_lock_irqsave(&blkif->pers_gnts_lock, irq_flags); if (add_persistent_gnt(blkif, persistent_gnt)) { + spin_unlock_irqrestore(&blkif->pers_gnts_lock, irq_flags); kfree(persistent_gnt); persistent_gnt = NULL; goto next; @@ -890,6 +916,7 @@ again: pr_debug("grant %u added to the tree of persistent grants, using %u/%u\n", persistent_gnt->gnt, blkif->persistent_gnt_c, xen_blkif_max_pgrants); + spin_unlock_irqrestore(&blkif->pers_gnts_lock, irq_flags); goto next; } if (use_persistent_gnts && !blkif->vbd.overflow_max_grants) { @@ -921,7 +948,7 @@ static int xen_blkbk_map_seg(struct pending_req *pending_req) { int rc; - rc = xen_blkbk_map(pending_req->blkif, pending_req->segments, + rc = xen_blkbk_map(pending_req->ring, pending_req->segments, pending_req->nr_segs, (pending_req->operation != BLKIF_OP_READ)); @@ -934,7 +961,7 @@ static int xen_blkbk_parse_indirect(struct blkif_request *req, struct phys_req *preq) { struct grant_page **pages = pending_req->indirect_pages; - struct xen_blkif *blkif = pending_req->blkif; + struct xen_blkif_ring *ring = pending_req->ring; int indirect_grefs, rc, n, nseg, i; struct blkif_request_segment *segments = NULL; @@ -945,7 +972,7 @@ static int xen_blkbk_parse_indirect(struct blkif_request *req, for (i = 0; i < indirect_grefs; i++) pages[i]->gref = req->u.indirect.indirect_grefs[i]; - rc = xen_blkbk_map(blkif, pages, indirect_grefs, true); + rc = xen_blkbk_map(ring, pages, indirect_grefs, true); if (rc) goto unmap; @@ -972,15 +999,16 @@ static int xen_blkbk_parse_indirect(struct blkif_request *req, unmap: if (segments) kunmap_atomic(segments); - xen_blkbk_unmap(blkif, pages, indirect_grefs); + xen_blkbk_unmap(ring, pages, indirect_grefs); return rc; } -static int dispatch_discard_io(struct xen_blkif *blkif, +static int dispatch_discard_io(struct xen_blkif_ring *ring, struct blkif_request *req) { int err = 0; int status = BLKIF_RSP_OKAY; + struct xen_blkif *blkif = ring->blkif; struct block_device *bdev = blkif->vbd.bdev; unsigned long secure; struct phys_req preq; @@ -1013,26 +1041,28 @@ fail_response: } else if (err) status = BLKIF_RSP_ERROR; - make_response(blkif, req->u.discard.id, req->operation, status); + make_response(ring, req->u.discard.id, req->operation, status); xen_blkif_put(blkif); return err; } -static int dispatch_other_io(struct xen_blkif *blkif, +static int dispatch_other_io(struct xen_blkif_ring *ring, struct blkif_request *req, struct pending_req *pending_req) { - free_req(blkif, pending_req); - make_response(blkif, req->u.other.id, req->operation, + free_req(ring, pending_req); + make_response(ring, req->u.other.id, req->operation, BLKIF_RSP_EOPNOTSUPP); return -EIO; } -static void xen_blk_drain_io(struct xen_blkif *blkif) +static void xen_blk_drain_io(struct xen_blkif_ring *ring) { + struct xen_blkif *blkif = ring->blkif; + atomic_set(&blkif->drain, 1); do { - if (atomic_read(&blkif->inflight) == 0) + if (atomic_read(&ring->inflight) == 0) break; wait_for_completion_interruptible_timeout( &blkif->drain_complete, HZ); @@ -1053,12 +1083,12 @@ static void __end_block_io_op(struct pending_req *pending_req, int error) if ((pending_req->operation == BLKIF_OP_FLUSH_DISKCACHE) && (error == -EOPNOTSUPP)) { pr_debug("flush diskcache op failed, not supported\n"); - xen_blkbk_flush_diskcache(XBT_NIL, pending_req->blkif->be, 0); + xen_blkbk_flush_diskcache(XBT_NIL, pending_req->ring->blkif->be, 0); pending_req->status = BLKIF_RSP_EOPNOTSUPP; } else if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) && (error == -EOPNOTSUPP)) { pr_debug("write barrier op failed, not supported\n"); - xen_blkbk_barrier(XBT_NIL, pending_req->blkif->be, 0); + xen_blkbk_barrier(XBT_NIL, pending_req->ring->blkif->be, 0); pending_req->status = BLKIF_RSP_EOPNOTSUPP; } else if (error) { pr_debug("Buffer not up-to-date at end of operation," @@ -1092,9 +1122,9 @@ 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 *blkif) +__do_block_io_op(struct xen_blkif_ring *ring) { - union blkif_back_rings *blk_rings = &blkif->blk_rings; + union blkif_back_rings *blk_rings = &ring->blk_rings; struct blkif_request req; struct pending_req *pending_req; RING_IDX rc, rp; @@ -1107,7 +1137,7 @@ __do_block_io_op(struct xen_blkif *blkif) if (RING_REQUEST_PROD_OVERFLOW(&blk_rings->common, rp)) { rc = blk_rings->common.rsp_prod_pvt; pr_warn("Frontend provided bogus ring requests (%d - %d = %d). Halting ring processing on dev=%04x\n", - rp, rc, rp - rc, blkif->vbd.pdevice); + rp, rc, rp - rc, ring->blkif->vbd.pdevice); return -EACCES; } while (rc != rp) { @@ -1120,14 +1150,14 @@ __do_block_io_op(struct xen_blkif *blkif) break; } - pending_req = alloc_req(blkif); + pending_req = alloc_req(ring); if (NULL == pending_req) { - blkif->st_oo_req++; + ring->blkif->st_oo_req++; more_to_do = 1; break; } - switch (blkif->blk_protocol) { + switch (ring->blkif->blk_protocol) { case BLKIF_PROTOCOL_NATIVE: memcpy(&req, RING_GET_REQUEST(&blk_rings->native, rc), sizeof(req)); break; @@ -1151,16 +1181,16 @@ __do_block_io_op(struct xen_blkif *blkif) case BLKIF_OP_WRITE_BARRIER: case BLKIF_OP_FLUSH_DISKCACHE: case BLKIF_OP_INDIRECT: - if (dispatch_rw_block_io(blkif, &req, pending_req)) + if (dispatch_rw_block_io(ring, &req, pending_req)) goto done; break; case BLKIF_OP_DISCARD: - free_req(blkif, pending_req); - if (dispatch_discard_io(blkif, &req)) + free_req(ring, pending_req); + if (dispatch_discard_io(ring, &req)) goto done; break; default: - if (dispatch_other_io(blkif, &req, pending_req)) + if (dispatch_other_io(ring, &req, pending_req)) goto done; break; } @@ -1173,13 +1203,13 @@ done: } static int -do_block_io_op(struct xen_blkif *blkif) +do_block_io_op(struct xen_blkif_ring *ring) { - union blkif_back_rings *blk_rings = &blkif->blk_rings; + union blkif_back_rings *blk_rings = &ring->blk_rings; int more_to_do; do { - more_to_do = __do_block_io_op(blkif); + more_to_do = __do_block_io_op(ring); if (more_to_do) break; @@ -1192,7 +1222,7 @@ do_block_io_op(struct xen_blkif *blkif) * Transmutation of the 'struct blkif_request' to a proper 'struct bio' * and call the 'submit_bio' to pass it to the underlying storage. */ -static int dispatch_rw_block_io(struct xen_blkif *blkif, +static int dispatch_rw_block_io(struct xen_blkif_ring *ring, struct blkif_request *req, struct pending_req *pending_req) { @@ -1220,17 +1250,17 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, switch (req_operation) { case BLKIF_OP_READ: - blkif->st_rd_req++; + ring->blkif->st_rd_req++; operation = READ; break; case BLKIF_OP_WRITE: - blkif->st_wr_req++; + ring->blkif->st_wr_req++; operation = WRITE_ODIRECT; break; case BLKIF_OP_WRITE_BARRIER: drain = true; case BLKIF_OP_FLUSH_DISKCACHE: - blkif->st_f_req++; + ring->blkif->st_f_req++; operation = WRITE_FLUSH; break; default: @@ -1255,7 +1285,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, preq.nr_sects = 0; - pending_req->blkif = blkif; + pending_req->ring = ring; pending_req->id = req->u.rw.id; pending_req->operation = req_operation; pending_req->status = BLKIF_RSP_OKAY; @@ -1282,12 +1312,12 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, goto fail_response; } - if (xen_vbd_translate(&preq, blkif, operation) != 0) { + if (xen_vbd_translate(&preq, ring->blkif, operation) != 0) { pr_debug("access denied: %s of [%llu,%llu] on dev=%04x\n", operation == READ ? "read" : "write", preq.sector_number, preq.sector_number + preq.nr_sects, - blkif->vbd.pdevice); + ring->blkif->vbd.pdevice); goto fail_response; } @@ -1299,7 +1329,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, if (((int)preq.sector_number|(int)seg[i].nsec) & ((bdev_logical_block_size(preq.bdev) >> 9) - 1)) { pr_debug("Misaligned I/O request from domain %d\n", - blkif->domid); + ring->blkif->domid); goto fail_response; } } @@ -1308,7 +1338,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, * issue the WRITE_FLUSH. */ if (drain) - xen_blk_drain_io(pending_req->blkif); + xen_blk_drain_io(pending_req->ring); /* * If we have failed at this point, we need to undo the M2P override, @@ -1323,8 +1353,8 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, * This corresponding xen_blkif_put is done in __end_block_io_op, or * below (in "!bio") if we are handling a BLKIF_OP_DISCARD. */ - xen_blkif_get(blkif); - atomic_inc(&blkif->inflight); + xen_blkif_get(ring->blkif); + atomic_inc(&ring->inflight); for (i = 0; i < nseg; i++) { while ((bio == NULL) || @@ -1372,19 +1402,19 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, blk_finish_plug(&plug); if (operation == READ) - blkif->st_rd_sect += preq.nr_sects; + ring->blkif->st_rd_sect += preq.nr_sects; else if (operation & WRITE) - blkif->st_wr_sect += preq.nr_sects; + ring->blkif->st_wr_sect += preq.nr_sects; return 0; fail_flush: - xen_blkbk_unmap(blkif, pending_req->segments, + xen_blkbk_unmap(ring, pending_req->segments, pending_req->nr_segs); fail_response: /* Haven't submitted any bio's yet. */ - make_response(blkif, req->u.rw.id, req_operation, BLKIF_RSP_ERROR); - free_req(blkif, pending_req); + make_response(ring, req->u.rw.id, req_operation, BLKIF_RSP_ERROR); + free_req(ring, pending_req); msleep(1); /* back off a bit */ return -EIO; @@ -1402,21 +1432,22 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, /* * Put a response on the ring on how the operation fared. */ -static void make_response(struct xen_blkif *blkif, u64 id, +static void make_response(struct xen_blkif_ring *ring, u64 id, unsigned short op, int st) { struct blkif_response resp; unsigned long flags; - union blkif_back_rings *blk_rings = &blkif->blk_rings; + union blkif_back_rings *blk_rings; int notify; resp.id = id; resp.operation = op; resp.status = st; - spin_lock_irqsave(&blkif->blk_ring_lock, flags); + spin_lock_irqsave(&ring->blk_ring_lock, flags); + blk_rings = &ring->blk_rings; /* Place on the response ring for the relevant domain. */ - switch (blkif->blk_protocol) { + switch (ring->blkif->blk_protocol) { case BLKIF_PROTOCOL_NATIVE: memcpy(RING_GET_RESPONSE(&blk_rings->native, blk_rings->native.rsp_prod_pvt), &resp, sizeof(resp)); @@ -1434,9 +1465,9 @@ static void make_response(struct xen_blkif *blkif, u64 id, } blk_rings->common.rsp_prod_pvt++; RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify); - spin_unlock_irqrestore(&blkif->blk_ring_lock, flags); + spin_unlock_irqrestore(&ring->blk_ring_lock, flags); if (notify) - notify_remote_via_irq(blkif->irq); + notify_remote_via_irq(ring->irq); } static int __init xen_blkif_init(void) diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index 68e87a037b99..dbdf4164c83f 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -269,34 +269,50 @@ struct persistent_gnt { struct list_head remove_node; }; +/* Per-ring information. */ +struct xen_blkif_ring { + /* Physical parameters of the comms window. */ + unsigned int irq; + union blkif_back_rings blk_rings; + void *blk_ring; + /* Private fields. */ + spinlock_t blk_ring_lock; + + wait_queue_head_t wq; + atomic_t inflight; + /* One thread per blkif ring. */ + struct task_struct *xenblkd; + unsigned int waiting_reqs; + + /* List of all 'pending_req' available */ + struct list_head pending_free; + /* And its spinlock. */ + spinlock_t pending_free_lock; + wait_queue_head_t pending_free_wq; + + struct work_struct free_work; + /* Thread shutdown wait queue. */ + wait_queue_head_t shutdown_wq; + struct xen_blkif *blkif; +}; + struct xen_blkif { /* Unique identifier for this interface. */ domid_t domid; unsigned int handle; - /* Physical parameters of the comms window. */ - unsigned int irq; /* Comms information. */ enum blkif_protocol blk_protocol; - union blkif_back_rings blk_rings; - void *blk_ring; /* The VBD attached to this interface. */ struct xen_vbd vbd; /* Back pointer to the backend_info. */ struct backend_info *be; - /* Private fields. */ - spinlock_t blk_ring_lock; atomic_t refcnt; - - wait_queue_head_t wq; /* for barrier (drain) requests */ struct completion drain_complete; atomic_t drain; - atomic_t inflight; - /* One thread per one blkif. */ - struct task_struct *xenblkd; - unsigned int waiting_reqs; /* tree to store persistent grants */ + spinlock_t pers_gnts_lock; struct rb_root persistent_gnts; unsigned int persistent_gnt_c; atomic_t persistent_gnt_in_use; @@ -311,12 +327,6 @@ struct xen_blkif { int free_pages_num; struct list_head free_pages; - /* List of all 'pending_req' available */ - struct list_head pending_free; - /* And its spinlock. */ - spinlock_t pending_free_lock; - wait_queue_head_t pending_free_wq; - /* statistics */ unsigned long st_print; unsigned long long st_rd_req; @@ -328,9 +338,9 @@ struct xen_blkif { unsigned long long st_wr_sect; struct work_struct free_work; - /* Thread shutdown wait queue. */ - wait_queue_head_t shutdown_wq; - unsigned int nr_ring_pages; + unsigned int nr_ring_pages; + /* All rings for this device. */ + struct xen_blkif_ring ring; }; struct seg_buf { @@ -352,7 +362,7 @@ struct grant_page { * response queued for it, with the saved 'id' passed back. */ struct pending_req { - struct xen_blkif *blkif; + struct xen_blkif_ring *ring; u64 id; int nr_segs; atomic_t pendcnt; @@ -394,7 +404,7 @@ int xen_blkif_xenbus_init(void); irqreturn_t xen_blkif_be_int(int irq, void *dev_id); int xen_blkif_schedule(void *arg); int xen_blkif_purge_persistent(void *arg); -void xen_blkbk_free_caches(struct xen_blkif *blkif); +void xen_blkbk_free_caches(struct xen_blkif_ring *ring); int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, struct backend_info *be, int state); diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index f53cff42f8da..e4bfc928035d 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -88,7 +88,7 @@ static void xen_update_blkif_status(struct xen_blkif *blkif) char name[BLKBACK_NAME_LEN]; /* Not ready to connect? */ - if (!blkif->irq || !blkif->vbd.bdev) + if (!blkif->ring.irq || !blkif->vbd.bdev) return; /* Already connected? */ @@ -113,10 +113,10 @@ static void xen_update_blkif_status(struct xen_blkif *blkif) } invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping); - blkif->xenblkd = kthread_run(xen_blkif_schedule, blkif, "%s", name); - if (IS_ERR(blkif->xenblkd)) { - err = PTR_ERR(blkif->xenblkd); - blkif->xenblkd = NULL; + 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; } @@ -125,6 +125,7 @@ static void xen_update_blkif_status(struct xen_blkif *blkif) 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); @@ -133,41 +134,40 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid) return ERR_PTR(-ENOMEM); blkif->domid = domid; - spin_lock_init(&blkif->blk_ring_lock); atomic_set(&blkif->refcnt, 1); - init_waitqueue_head(&blkif->wq); init_completion(&blkif->drain_complete); - atomic_set(&blkif->drain, 0); - blkif->st_print = jiffies; - blkif->persistent_gnts.rb_node = NULL; + INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); spin_lock_init(&blkif->free_pages_lock); INIT_LIST_HEAD(&blkif->free_pages); INIT_LIST_HEAD(&blkif->persistent_purge_list); - blkif->free_pages_num = 0; - atomic_set(&blkif->persistent_gnt_in_use, 0); - atomic_set(&blkif->inflight, 0); + blkif->st_print = jiffies; INIT_WORK(&blkif->persistent_purge_work, xen_blkbk_unmap_purged_grants); - INIT_LIST_HEAD(&blkif->pending_free); - INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); - spin_lock_init(&blkif->pending_free_lock); - init_waitqueue_head(&blkif->pending_free_wq); - init_waitqueue_head(&blkif->shutdown_wq); + 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); return blkif; } -static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t *gref, +static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, unsigned int nr_grefs, unsigned int evtchn) { int err; + struct xen_blkif *blkif = ring->blkif; /* Already connected through? */ - if (blkif->irq) + if (ring->irq) return 0; err = xenbus_map_ring_valloc(blkif->be->dev, gref, nr_grefs, - &blkif->blk_ring); + &ring->blk_ring); if (err < 0) return err; @@ -175,24 +175,24 @@ static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t *gref, case BLKIF_PROTOCOL_NATIVE: { struct blkif_sring *sring; - sring = (struct blkif_sring *)blkif->blk_ring; - BACK_RING_INIT(&blkif->blk_rings.native, sring, + sring = (struct blkif_sring *)ring->blk_ring; + BACK_RING_INIT(&ring->blk_rings.native, sring, XEN_PAGE_SIZE * nr_grefs); break; } case BLKIF_PROTOCOL_X86_32: { struct blkif_x86_32_sring *sring_x86_32; - sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring; - BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, + sring_x86_32 = (struct blkif_x86_32_sring *)ring->blk_ring; + BACK_RING_INIT(&ring->blk_rings.x86_32, sring_x86_32, XEN_PAGE_SIZE * nr_grefs); break; } case BLKIF_PROTOCOL_X86_64: { struct blkif_x86_64_sring *sring_x86_64; - sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring; - BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, + sring_x86_64 = (struct blkif_x86_64_sring *)ring->blk_ring; + BACK_RING_INIT(&ring->blk_rings.x86_64, sring_x86_64, XEN_PAGE_SIZE * nr_grefs); break; } @@ -202,13 +202,13 @@ static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t *gref, err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, xen_blkif_be_int, 0, - "blkif-backend", blkif); + "blkif-backend", ring); if (err < 0) { - xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); - blkif->blk_rings.common.sring = NULL; + xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); + ring->blk_rings.common.sring = NULL; return err; } - blkif->irq = err; + ring->irq = err; return 0; } @@ -217,35 +217,36 @@ 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; - if (blkif->xenblkd) { - kthread_stop(blkif->xenblkd); - wake_up(&blkif->shutdown_wq); - blkif->xenblkd = NULL; + if (ring->xenblkd) { + kthread_stop(ring->xenblkd); + wake_up(&ring->shutdown_wq); + ring->xenblkd = NULL; } /* 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(&blkif->inflight) > 0) + if (atomic_read(&ring->inflight) > 0) return -EBUSY; - if (blkif->irq) { - unbind_from_irqhandler(blkif->irq, blkif); - blkif->irq = 0; + if (ring->irq) { + unbind_from_irqhandler(ring->irq, ring); + ring->irq = 0; } - if (blkif->blk_rings.common.sring) { - xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); - blkif->blk_rings.common.sring = NULL; + if (ring->blk_rings.common.sring) { + xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); + ring->blk_rings.common.sring = NULL; } /* Remove all persistent grants and the cache of ballooned pages. */ - xen_blkbk_free_caches(blkif); + xen_blkbk_free_caches(ring); /* Check that there is no request in use */ - list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) { + list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { list_del(&req->free_list); for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) @@ -835,6 +836,7 @@ static int connect_ring(struct backend_info *be) 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); @@ -923,7 +925,7 @@ static int connect_ring(struct backend_info *be) req = kzalloc(sizeof(*req), GFP_KERNEL); if (!req) goto fail; - list_add_tail(&req->free_list, &be->blkif->pending_free); + list_add_tail(&req->free_list, &ring->pending_free); for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL); if (!req->segments[j]) @@ -938,7 +940,7 @@ static int connect_ring(struct backend_info *be) } /* Map the shared frame, irq etc. */ - err = xen_blkif_map(be->blkif, ring_ref, nr_grefs, evtchn); + err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn); if (err) { xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn); return err; @@ -947,7 +949,7 @@ static int connect_ring(struct backend_info *be) return 0; fail: - list_for_each_entry_safe(req, n, &be->blkif->pending_free, free_list) { + list_for_each_entry_safe(req, n, &ring->pending_free, free_list) { list_del(&req->free_list); for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { if (!req->segments[j]) -- 2.20.1