diff options
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 26 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.h | 3 |
2 files changed, 23 insertions, 6 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 9ab884999420..24e6426cf258 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -140,6 +140,7 @@ static ssize_t mem_used_total_show(struct device *dev, return sprintf(buf, "%llu\n", val); } +/* flag operations needs meta->tb_lock */ static int zram_test_flag(struct zram_meta *meta, u32 index, enum zram_pageflags flag) { @@ -228,6 +229,7 @@ static struct zram_meta *zram_meta_alloc(u64 disksize) goto free_table; } + rwlock_init(&meta->tb_lock); return meta; free_table: @@ -280,6 +282,7 @@ static void handle_zero_page(struct bio_vec *bvec) flush_dcache_page(page); } +/* NOTE: caller should hold meta->tb_lock with write-side */ static void zram_free_page(struct zram *zram, size_t index) { struct zram_meta *meta = zram->meta; @@ -319,20 +322,26 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index) size_t clen = PAGE_SIZE; unsigned char *cmem; struct zram_meta *meta = zram->meta; - unsigned long handle = meta->table[index].handle; + unsigned long handle; + u16 size; + + read_lock(&meta->tb_lock); + handle = meta->table[index].handle; + size = meta->table[index].size; if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) { + read_unlock(&meta->tb_lock); clear_page(mem); return 0; } cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO); - if (meta->table[index].size == PAGE_SIZE) + if (size == PAGE_SIZE) copy_page(mem, cmem); else - ret = lzo1x_decompress_safe(cmem, meta->table[index].size, - mem, &clen); + ret = lzo1x_decompress_safe(cmem, size, mem, &clen); zs_unmap_object(meta->mem_pool, handle); + read_unlock(&meta->tb_lock); /* Should NEVER happen. Return bio error if it does. */ if (unlikely(ret != LZO_E_OK)) { @@ -353,11 +362,14 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, struct zram_meta *meta = zram->meta; page = bvec->bv_page; + read_lock(&meta->tb_lock); if (unlikely(!meta->table[index].handle) || zram_test_flag(meta, index, ZRAM_ZERO)) { + read_unlock(&meta->tb_lock); handle_zero_page(bvec); return 0; } + read_unlock(&meta->tb_lock); if (is_partial_io(bvec)) /* Use a temporary buffer to decompress the page */ @@ -433,10 +445,12 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, if (page_zero_filled(uncmem)) { kunmap_atomic(user_mem); /* Free memory associated with this sector now. */ + write_lock(&zram->meta->tb_lock); zram_free_page(zram, index); + zram_set_flag(meta, index, ZRAM_ZERO); + write_unlock(&zram->meta->tb_lock); atomic_inc(&zram->stats.pages_zero); - zram_set_flag(meta, index, ZRAM_ZERO); ret = 0; goto out; } @@ -486,10 +500,12 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, * Free memory associated with this sector * before overwriting unused sectors. */ + write_lock(&zram->meta->tb_lock); zram_free_page(zram, index); meta->table[index].handle = handle; meta->table[index].size = clen; + write_unlock(&zram->meta->tb_lock); /* Update stats */ atomic64_add(clen, &zram->stats.compr_size); diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index 81b0170de369..c3f453f04974 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -83,6 +83,7 @@ struct zram_stats { }; struct zram_meta { + rwlock_t tb_lock; /* protect table */ void *compress_workmem; void *compress_buffer; struct table *table; @@ -96,7 +97,7 @@ struct zram_slot_free { struct zram { struct zram_meta *meta; - struct rw_semaphore lock; /* protect compression buffers, table, + struct rw_semaphore lock; /* protect compression buffers, * reads and writes */ |