diff options
Diffstat (limited to 'drivers/block/xen-blkback/blkback.c')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 50 |
1 files changed, 33 insertions, 17 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index a295ad6a1674..698a52a96d2d 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -173,7 +173,7 @@ 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 do_block_io_op(struct xen_blkif *blkif, unsigned int *eoi_flags); static int dispatch_rw_block_io(struct xen_blkif *blkif, struct blkif_request *req, struct pending_req *pending_req); @@ -594,6 +594,8 @@ 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; while (!kthread_should_stop()) { if (try_to_freeze()) @@ -617,16 +619,23 @@ int xen_blkif_schedule(void *arg) if (timeout == 0) goto purge_gnt_list; + do_eoi = blkif->waiting_reqs; + blkif->waiting_reqs = 0; smp_mb(); /* clear flag *before* checking for work */ - ret = do_block_io_op(blkif); + ret = do_block_io_op(blkif, &eoi_flags); if (ret > 0) blkif->waiting_reqs = 1; if (ret == -EACCES) wait_event_interruptible(blkif->shutdown_wq, kthread_should_stop()); + if (do_eoi && !blkif->waiting_reqs) { + xen_irq_lateeoi(blkif->irq, eoi_flags); + eoi_flags |= XEN_EOI_FLAG_SPURIOUS; + } + purge_gnt_list: if (blkif->vbd.feature_gnt_persistent && time_after(jiffies, blkif->next_lru)) { @@ -816,8 +825,11 @@ again: pages[i]->page = persistent_gnt->page; pages[i]->persistent_gnt = persistent_gnt; } else { - if (get_free_page(blkif, &pages[i]->page)) - goto out_of_memory; + if (get_free_page(blkif, &pages[i]->page)) { + put_free_pages(blkif, pages_to_gnt, segs_to_map); + ret = -ENOMEM; + goto out; + } addr = vaddr(pages[i]->page); pages_to_gnt[segs_to_map] = pages[i]->page; pages[i]->persistent_gnt = NULL; @@ -833,10 +845,8 @@ again: break; } - if (segs_to_map) { + if (segs_to_map) ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map); - BUG_ON(ret); - } /* * Now swizzle the MFN in our domain with the MFN from the other domain @@ -851,7 +861,7 @@ again: pr_debug("invalid buffer -- could not remap it\n"); put_free_pages(blkif, &pages[seg_idx]->page, 1); pages[seg_idx]->handle = BLKBACK_INVALID_HANDLE; - ret |= 1; + ret |= !ret; goto next; } pages[seg_idx]->handle = map[new_map_idx].handle; @@ -903,15 +913,18 @@ next: } segs_to_map = 0; last_map = map_until; - if (map_until != num) + if (!ret && map_until != num) goto again; - return ret; +out: + for (i = last_map; i < num; i++) { + /* Don't zap current batch's valid persistent grants. */ + if(i >= map_until) + pages[i]->persistent_gnt = NULL; + pages[i]->handle = BLKBACK_INVALID_HANDLE; + } -out_of_memory: - pr_alert("%s: out of memory\n", __func__); - put_free_pages(blkif, pages_to_gnt, segs_to_map); - return -ENOMEM; + return ret; } static int xen_blkbk_map_seg(struct pending_req *pending_req) @@ -1094,7 +1107,7 @@ 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 *blkif) +__do_block_io_op(struct xen_blkif *blkif, unsigned int *eoi_flags) { union blkif_back_rings *blk_rings = &blkif->blk_rings; struct blkif_request req; @@ -1117,6 +1130,9 @@ __do_block_io_op(struct xen_blkif *blkif) 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; @@ -1175,13 +1191,13 @@ done: } static int -do_block_io_op(struct xen_blkif *blkif) +do_block_io_op(struct xen_blkif *blkif, unsigned int *eoi_flags) { union blkif_back_rings *blk_rings = &blkif->blk_rings; int more_to_do; do { - more_to_do = __do_block_io_op(blkif); + more_to_do = __do_block_io_op(blkif, eoi_flags); if (more_to_do) break; |