diff options
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 123 |
1 files changed, 118 insertions, 5 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 195b3372241c..4ddc18a0a04f 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -454,6 +454,95 @@ void zram_page_end_io(struct bio *bio) bio_put(bio); } +/* + * Returns 1 if the submission is successful. + */ +static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec, + unsigned long entry, struct bio *parent) +{ + struct bio *bio; + + bio = bio_alloc(GFP_ATOMIC, 1); + if (!bio) + return -ENOMEM; + + bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9); + bio->bi_bdev = zram->bdev; + if (!bio_add_page(bio, bvec->bv_page, bvec->bv_len, bvec->bv_offset)) { + bio_put(bio); + return -EIO; + } + + if (!parent) { + bio->bi_opf = REQ_OP_READ; + bio->bi_end_io = zram_page_end_io; + } else { + bio->bi_opf = parent->bi_opf; + bio_chain(bio, parent); + } + + submit_bio(bio); + return 1; +} + +struct zram_work { + struct work_struct work; + struct zram *zram; + unsigned long entry; + struct bio *bio; +}; + +#if PAGE_SIZE != 4096 +static void zram_sync_read(struct work_struct *work) +{ + struct bio_vec bvec; + struct zram_work *zw = container_of(work, struct zram_work, work); + struct zram *zram = zw->zram; + unsigned long entry = zw->entry; + struct bio *bio = zw->bio; + + read_from_bdev_async(zram, &bvec, entry, bio); +} + +/* + * Block layer want one ->make_request_fn to be active at a time + * so if we use chained IO with parent IO in same context, + * it's a deadlock. To avoid, it, it uses worker thread context. + */ +static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec, + unsigned long entry, struct bio *bio) +{ + struct zram_work work; + + work.zram = zram; + work.entry = entry; + work.bio = bio; + + INIT_WORK_ONSTACK(&work.work, zram_sync_read); + queue_work(system_unbound_wq, &work.work); + flush_work(&work.work); + destroy_work_on_stack(&work.work); + + return 1; +} +#else +static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec, + unsigned long entry, struct bio *bio) +{ + WARN_ON(1); + return -EIO; +} +#endif + +static int read_from_bdev(struct zram *zram, struct bio_vec *bvec, + unsigned long entry, struct bio *parent, bool sync) +{ + if (sync) + return read_from_bdev_sync(zram, bvec, entry, parent); + else + return read_from_bdev_async(zram, bvec, entry, parent); +} + static int write_to_bdev(struct zram *zram, struct bio_vec *bvec, u32 index, struct bio *parent, unsigned long *pentry) @@ -514,6 +603,12 @@ static int write_to_bdev(struct zram *zram, struct bio_vec *bvec, { return -EIO; } + +static int read_from_bdev(struct zram *zram, struct bio_vec *bvec, + unsigned long entry, struct bio *parent, bool sync) +{ + return -EIO; +} static void zram_wb_clear(struct zram *zram, u32 index) {} #endif @@ -773,13 +868,31 @@ static void zram_free_page(struct zram *zram, size_t index) zram_set_obj_size(zram, index, 0); } -static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index) +static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, + struct bio *bio, bool partial_io) { int ret; unsigned long handle; unsigned int size; void *src, *dst; + if (zram_wb_enabled(zram)) { + zram_slot_lock(zram, index); + if (zram_test_flag(zram, index, ZRAM_WB)) { + struct bio_vec bvec; + + zram_slot_unlock(zram, index); + + bvec.bv_page = page; + bvec.bv_len = PAGE_SIZE; + bvec.bv_offset = 0; + return read_from_bdev(zram, &bvec, + zram_get_element(zram, index), + bio, partial_io); + } + zram_slot_unlock(zram, index); + } + if (zram_same_page_read(zram, index, page, 0, PAGE_SIZE)) return 0; @@ -812,7 +925,7 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index) } static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, - u32 index, int offset) + u32 index, int offset, struct bio *bio) { int ret; struct page *page; @@ -825,7 +938,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, return -ENOMEM; } - ret = __zram_bvec_read(zram, page, index); + ret = __zram_bvec_read(zram, page, index, bio, is_partial_io(bvec)); if (unlikely(ret)) goto out; @@ -988,7 +1101,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, if (!page) return -ENOMEM; - ret = __zram_bvec_read(zram, page, index); + ret = __zram_bvec_read(zram, page, index, bio, true); if (ret) goto out; @@ -1065,7 +1178,7 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, if (!is_write) { atomic64_inc(&zram->stats.num_reads); - ret = zram_bvec_read(zram, bvec, index, offset); + ret = zram_bvec_read(zram, bvec, index, offset, bio); flush_dcache_page(bvec->bv_page); } else { atomic64_inc(&zram->stats.num_writes); |