slot_free() basically completely resets the slots by clearing all of its flags and attributes. While zram_writeback_complete() restores some of flags back (those that are necessary for async read decompression) we still lose a lot of slot's metadata. For example, slot's ac-time, or ZRAM_INCOMPRESSIBLE. Do not slot_free() on writeback, instead clear only those flags/attrs that we need to clear. Fixes: d38fab605c667 ("zram: introduce compressed data writeback") Signed-off-by: Sergey Senozhatsky --- drivers/block/zram/zram_drv.c | 39 +++++++++++++---------------------- 1 file changed, 14 insertions(+), 25 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 1b0e1c02ece7..5ecc4ba40e9d 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -917,9 +917,8 @@ static void zram_account_writeback_submit(struct zram *zram) static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req) { - u32 size, index = req->pps->index; - int err, prio; - bool huge; + u32 index = req->pps->index; + int err; err = blk_status_to_errno(req->bio.bi_status); if (err) { @@ -946,28 +945,13 @@ static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req) goto out; } - if (zram->compressed_wb) { - /* - * ZRAM_WB slots get freed, we need to preserve data required - * for read decompression. - */ - size = get_slot_size(zram, index); - prio = get_slot_comp_priority(zram, index); - huge = test_slot_flag(zram, index, ZRAM_HUGE); - } - - slot_free(zram, index); - set_slot_flag(zram, index, ZRAM_WB); + clear_slot_flag(zram, index, ZRAM_IDLE); + if (test_slot_flag(zram, index, ZRAM_HUGE)) + atomic64_dec(&zram->stats.huge_pages); + atomic64_sub(get_slot_size(zram, index), &zram->stats.compr_data_size); + zs_free(zram->mem_pool, get_slot_handle(zram, index)); set_slot_handle(zram, index, req->blk_idx); - - if (zram->compressed_wb) { - if (huge) - set_slot_flag(zram, index, ZRAM_HUGE); - set_slot_size(zram, index, size); - set_slot_comp_priority(zram, index, prio); - } - - atomic64_inc(&zram->stats.pages_stored); + set_slot_flag(zram, index, ZRAM_WB); out: slot_unlock(zram, index); @@ -2030,8 +2014,13 @@ static void slot_free(struct zram *zram, u32 index) set_slot_comp_priority(zram, index, 0); if (test_slot_flag(zram, index, ZRAM_HUGE)) { + /* + * Writeback completion decrements ->huge_pages but keeps + * ZRAM_HUGE flag for deferred decompression path. + */ + if (!test_slot_flag(zram, index, ZRAM_WB)) + atomic64_dec(&zram->stats.huge_pages); clear_slot_flag(zram, index, ZRAM_HUGE); - atomic64_dec(&zram->stats.huge_pages); } if (test_slot_flag(zram, index, ZRAM_WB)) { -- 2.53.0.851.ga537e3e6e9-goog