diff options
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 24 |
1 files changed, 14 insertions, 10 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index ea158fe0c9a..4662217c61b 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -341,7 +341,7 @@ static void purge_persistent_gnt(struct xen_blkif *blkif) struct persistent_gnt *persistent_gnt; struct rb_node *n; unsigned int num_clean, total; - bool scan_used = false; + bool scan_used = false, clean_used = false; struct rb_root *root; if (blkif->persistent_gnt_c < xen_blkif_max_pgrants || @@ -358,9 +358,8 @@ static void purge_persistent_gnt(struct xen_blkif *blkif) num_clean = (xen_blkif_max_pgrants / 100) * LRU_PERCENT_CLEAN; num_clean = blkif->persistent_gnt_c - xen_blkif_max_pgrants + num_clean; num_clean = min(blkif->persistent_gnt_c, num_clean); - if (num_clean > - (blkif->persistent_gnt_c - - atomic_read(&blkif->persistent_gnt_in_use))) + if ((num_clean == 0) || + (num_clean > (blkif->persistent_gnt_c - atomic_read(&blkif->persistent_gnt_in_use)))) return; /* @@ -383,6 +382,11 @@ purge_list: BUG_ON(persistent_gnt->handle == BLKBACK_INVALID_HANDLE); + if (clean_used) { + clear_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags); + continue; + } + if (test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags)) continue; if (!scan_used && @@ -400,18 +404,18 @@ purge_list: * grants that were used since last purge in order to cope * with the requested num */ - if (!scan_used) { + if (!scan_used && !clean_used) { pr_debug(DRV_PFX "Still missing %u purged frames\n", num_clean); scan_used = true; goto purge_list; } finished: - /* Remove the "used" flag from all the persistent grants */ - foreach_grant_safe(persistent_gnt, n, root, node) { - BUG_ON(persistent_gnt->handle == - BLKBACK_INVALID_HANDLE); - clear_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags); + if (!clean_used) { + pr_debug(DRV_PFX "Finished scanning for grants to clean, removing used flag\n"); + clean_used = true; + goto purge_list; } + blkif->persistent_gnt_c -= (total - num_clean); blkif->vbd.overflow_max_grants = 0; |