Prepare to reduce locking by using atomic 32 bit access to the fields. To ensure this we need to use the _ONCE macros.
https://virtuozzo.atlassian.net/browse/VSTOR-91659 Signed-off-by: Alexander Atanasov <alexander.atana...@virtuozzo.com> --- drivers/md/dm-ploop-bat.c | 20 ++++++++++---------- drivers/md/dm-ploop-cmd.c | 28 ++++++++++++++-------------- drivers/md/dm-ploop-map.c | 24 +++++++++++++----------- drivers/md/dm-ploop.h | 2 +- 4 files changed, 38 insertions(+), 36 deletions(-) diff --git a/drivers/md/dm-ploop-bat.c b/drivers/md/dm-ploop-bat.c index f28bd5d7b322..886a05cdd23a 100644 --- a/drivers/md/dm-ploop-bat.c +++ b/drivers/md/dm-ploop-bat.c @@ -143,9 +143,9 @@ bool ploop_try_update_bat_entry(struct ploop *ploop, u32 clu, u8 level, u32 dst_ clu = ploop_bat_clu_idx_in_page(clu); /* relative offset */ - if (md->bat_levels[clu] == level) { + if (READ_ONCE(md->bat_levels[clu]) == level) { bat_entries = md->kmpage; - bat_entries[clu] = dst_clu; + WRITE_ONCE(bat_entries[clu], dst_clu); return true; } return false; @@ -287,11 +287,11 @@ static int ploop_convert_bat_entries(struct ploop *ploop, struct rb_root *md_roo page_id++; for (; i <= end; i++) { - if (bat_entries[i] > max_file_clu) + if (READ_ONCE(bat_entries[i]) > max_file_clu) ret = -EPROTO; - if (!bat_entries[i]) - bat_entries[i] = BAT_ENTRY_NONE; - if (bat_entries[i] < bat_clusters) + if (!READ_ONCE(bat_entries[i])) + WRITE_ONCE(bat_entries[i], BAT_ENTRY_NONE); + if (READ_ONCE(bat_entries[i]) < bat_clusters) ret = -EXDEV; } @@ -431,21 +431,21 @@ static void ploop_apply_delta_mappings(struct ploop *ploop, if (clu == nr_be - 1) stop = true; - if (bat_entries[i] != BAT_ENTRY_NONE) { + if (READ_ONCE(bat_entries[i]) != BAT_ENTRY_NONE) { /* md0 is already populated */ WARN_ON_ONCE(md->id && is_top_level); goto set_not_hole; } if (!is_raw) - dst_clu = d_bat_entries[i]; + dst_clu = READ_ONCE(d_bat_entries[i]); else dst_clu = clu; if (dst_clu == BAT_ENTRY_NONE) continue; - md->bat_levels[i] = level; - bat_entries[i] = dst_clu; + WRITE_ONCE(md->bat_levels[i], level); + WRITE_ONCE(bat_entries[i], dst_clu); set_not_hole: if (is_top_level) ploop_set_not_hole(ploop, bat_entries[i]); diff --git a/drivers/md/dm-ploop-cmd.c b/drivers/md/dm-ploop-cmd.c index d9d41d79d937..25ca9db4eeb8 100644 --- a/drivers/md/dm-ploop-cmd.c +++ b/drivers/md/dm-ploop-cmd.c @@ -47,7 +47,7 @@ static void ploop_advance_holes_bitmap(struct ploop *ploop, for (; i <= end; i++) { if (!ploop_md_page_cluster_is_in_top_delta(ploop, md, i)) continue; - dst_clu = bat_entries[i]; + dst_clu = READ_ONCE(bat_entries[i]); /* This may happen after grow->shrink->(now) grow */ if (dst_clu < ploop->hb_nr && test_bit(dst_clu, ploop->holes_bitmap)) { @@ -162,7 +162,7 @@ static u32 ploop_find_bat_entry(struct ploop *ploop, u32 dst_clu, bool *is_locke ploop_init_be_iter(ploop, md->id, &i, &end); bat_entries = md->kmpage; for (; i <= end; i++) { - if (bat_entries[i] != dst_clu) + if (READ_ONCE(bat_entries[i]) != dst_clu) continue; if (ploop_md_page_cluster_is_in_top_delta(ploop, md, i)) { clu = ploop_page_clu_idx_to_bat_clu(md->id, i); @@ -735,17 +735,17 @@ static void notify_delta_merged(struct ploop *ploop, u8 level, stop = true; /* deltas above @level become renumbered */ - if (bat_entries[i] != BAT_ENTRY_NONE && - md->bat_levels[i] > level) { + if (READ_ONCE(bat_entries[i]) != BAT_ENTRY_NONE && + READ_ONCE(md->bat_levels[i]) > level) { md->bat_levels[i]--; continue; } - if (bat_entries[i] != BAT_ENTRY_NONE && - md->bat_levels[i] < level) + if (READ_ONCE(bat_entries[i]) != BAT_ENTRY_NONE && + READ_ONCE(md->bat_levels[i]) < level) continue; - if (d_bat_entries[i] == BAT_ENTRY_NONE) { + if (READ_ONCE(d_bat_entries[i]) == BAT_ENTRY_NONE) { WARN_ON_ONCE(bat_entries[i] != BAT_ENTRY_NONE); continue; } @@ -757,9 +757,9 @@ static void notify_delta_merged(struct ploop *ploop, u8 level, */ WRITE_ONCE(bat_entries[i], READ_ONCE(d_bat_entries[i])); if (!forward) - md->bat_levels[i] = level - 1; + WRITE_ONCE(md->bat_levels[i], level - 1); else - md->bat_levels[i] = level; + WRITE_ONCE(md->bat_levels[i], level); } if (stop) break; @@ -985,13 +985,13 @@ static int process_flip_upper_deltas(struct ploop *ploop) ploop_init_be_iter(ploop, md->id, &i, &end); bat_entries = md->kmpage; for (; i <= end; i++) { - if (bat_entries[i] == BAT_ENTRY_NONE) + if (READ_ONCE(bat_entries[i]) == BAT_ENTRY_NONE) continue; - if (md->bat_levels[i] == level) { - md->bat_levels[i] = ploop_top_level(ploop); + if (READ_ONCE(md->bat_levels[i]) == level) { + WRITE_ONCE(md->bat_levels[i], ploop_top_level(ploop)); clear_bit(bat_entries[i], holes_bitmap); - } else if (md->bat_levels[i] == ploop_top_level(ploop)) { - md->bat_levels[i] = level; + } else if (READ_ONCE(md->bat_levels[i]) == ploop_top_level(ploop)) { + WRITE_ONCE(md->bat_levels[i], level); } } } diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c index 634f0679be3f..221e97ba84a9 100644 --- a/drivers/md/dm-ploop-map.c +++ b/drivers/md/dm-ploop-map.c @@ -723,9 +723,9 @@ static void ploop_release_cluster(struct ploop *ploop, u32 clu) clu = ploop_bat_clu_idx_in_page(clu); /* relative to page */ bat_entries = md->kmpage; - dst_clu = bat_entries[clu]; - bat_entries[clu] = BAT_ENTRY_NONE; - md->bat_levels[clu] = 0; + dst_clu = READ_ONCE(bat_entries[clu]); + WRITE_ONCE(bat_entries[clu], BAT_ENTRY_NONE); + WRITE_ONCE(md->bat_levels[clu], 0); ploop_hole_set_bit(dst_clu, ploop); } @@ -793,8 +793,8 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop, } if (success) { - bat_entries[i] = dst_clu[i]; - md->bat_levels[i] = ploop_top_level(ploop); + WRITE_ONCE(bat_entries[i], READ_ONCE(dst_clu[i])); + WRITE_ONCE(md->bat_levels[i], ploop_top_level(ploop)); } else { ploop_hole_set_bit(i + off, ploop); } @@ -977,7 +977,7 @@ static void ploop_bat_page_zero_cluster(struct ploop *ploop, clu = ploop_bat_clu_idx_in_page(clu); to = kmap_local_page(piwb->bat_page); - to[clu] = 0; + WRITE_ONCE(to[clu], 0); kunmap_local(to); } @@ -1085,14 +1085,16 @@ static int ploop_alloc_cluster(struct ploop *ploop, struct ploop_index_wb *piwb, bool already_alloced = false; map_index_t *to; int ret = 0; + u32 tmp_clu; /* Cluster index related to the page[page_id] start */ clu -= piwb->page_id * PAGE_SIZE / sizeof(map_index_t) - PLOOP_MAP_OFFSET; to = kmap_local_page(piwb->bat_page); - if (to[clu]) { + tmp_clu = READ_ONCE(to[clu]); + if (tmp_clu) { /* Already mapped by one of previous bios */ - *dst_clu = to[clu]; + *dst_clu = tmp_clu; already_alloced = true; } kunmap_local(to); @@ -1105,7 +1107,7 @@ static int ploop_alloc_cluster(struct ploop *ploop, struct ploop_index_wb *piwb, goto out; to = kmap_local_page(piwb->bat_page); - to[clu] = *dst_clu; + WRITE_ONCE(to[clu], *dst_clu); kunmap_local(to); out: return ret; @@ -1388,7 +1390,7 @@ static void ploop_submit_cow_index_wb(struct ploop_cow *cow) to = kmap_local_page(piwb->bat_page); WARN_ON(to[clu]); - to[clu] = cow->dst_clu; + WRITE_ONCE(to[clu], cow->dst_clu); kunmap_local(to); /* Prevent double clearing of holes_bitmap bit on complete_cow() */ @@ -1725,7 +1727,7 @@ static void ploop_process_one_discard_pio(struct ploop *ploop, struct pio *pio) pio->bi_status = BLK_STS_IOERR; goto err; } else { - to[clu] = 0; + WRITE_ONCE(to[clu], 0); list_add_tail(&pio->list, &piwb->ready_data_pios); } kunmap_local(to); diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h index 3783d42a6162..b42baccf9a00 100644 --- a/drivers/md/dm-ploop.h +++ b/drivers/md/dm-ploop.h @@ -427,7 +427,7 @@ static inline u32 ploop_bat_entries(struct ploop *ploop, u32 clu, clu = ploop_bat_clu_idx_in_page(clu); if (bat_level) - *bat_level = md->bat_levels[clu]; + *bat_level = READ_ONCE(md->bat_levels[clu]); if (md_ret) *md_ret = md; -- 2.43.0 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
