static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, int offset) { int ret; u32 store_offset; size_t clen; struct zobj_header *zheader; struct page *page, *page_store; unsigned char *user_mem, *cmem, *src, *uncmem = NULL; page = bvec->bv_page; src = zram->compress_buffer; if (is_partial_io(bvec)) { /* * This is a partial IO. We need to read the full page * before to write the changes. */ uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!uncmem) { pr_info("Error allocating temp memory!\n"); ret = -ENOMEM; goto out; } ret = zram_read_before_write(zram, uncmem, index); if (ret) { kfree(uncmem); goto out; } } /* * System overwrites unused sectors. Free memory associated * with this sector now. */ if (zram->table[index].page || zram_test_flag(zram, index, ZRAM_ZERO)) zram_free_page(zram, index); user_mem = kmap_atomic(page, KM_USER0); if (is_partial_io(bvec)) memcpy(uncmem + offset, user_mem + bvec->bv_offset, bvec->bv_len); else uncmem = user_mem; if (page_zero_filled(uncmem)) { kunmap_atomic(user_mem, KM_USER0); if (is_partial_io(bvec)) kfree(uncmem); zram_stat_inc(&zram->stats.pages_zero); zram_set_flag(zram, index, ZRAM_ZERO); ret = 0; goto out; } COMPRESS(uncmem, PAGE_SIZE, src, &clen, zram->compress_workmem); ret = 0; kunmap_atomic(user_mem, KM_USER0); if (is_partial_io(bvec)) kfree(uncmem); if (unlikely(ret != 0)) { pr_err("Compression failed! err=%d\n", ret); goto out; } /* * Page is incompressible. Store it as-is (uncompressed) * since we do not want to return too many disk write * errors which has side effect of hanging the system. */ if (unlikely(clen > max_zpage_size)) { clen = PAGE_SIZE; page_store = alloc_page(GFP_NOIO | __GFP_HIGHMEM); if (unlikely(!page_store)) { pr_info("Error allocating memory for " "incompressible page: %u\n", index); ret = -ENOMEM; goto out; } store_offset = 0; zram_set_flag(zram, index, ZRAM_UNCOMPRESSED); zram_stat_inc(&zram->stats.pages_expand); zram->table[index].page = page_store; src = kmap_atomic(page, KM_USER0); goto memstore; } if (xv_malloc(zram->mem_pool, clen + sizeof(*zheader), &zram->table[index].page, &store_offset, GFP_NOIO | __GFP_HIGHMEM)) { pr_info("Error allocating memory for compressed " "page: %u, size=%zu\n", index, clen); ret = -ENOMEM; goto out; } memstore: zram->table[index].offset = store_offset; cmem = kmap_atomic(zram->table[index].page, KM_USER1) + zram->table[index].offset; #if 0 /* Back-reference needed for memory defragmentation */ if (!zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)) { zheader = (struct zobj_header *)cmem; zheader->table_idx = index; cmem += sizeof(*zheader); } #endif memcpy(cmem, src, clen); kunmap_atomic(cmem, KM_USER1); if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) kunmap_atomic(src, KM_USER0); /* Update stats */ zram_stat64_add(zram, &zram->stats.compr_size, clen); zram_stat_inc(&zram->stats.pages_stored); if (clen <= PAGE_SIZE / 2) zram_stat_inc(&zram->stats.good_compress); return 0; out: if (ret) zram_stat64_inc(zram, &zram->stats.failed_writes); return ret; }
static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, int offset) { int ret = 0; size_t clen; unsigned long handle; struct page *page; unsigned char *user_mem, *cmem, *src, *uncmem = NULL; page = bvec->bv_page; src = zram->compress_buffer; if (is_partial_io(bvec)) { /* * This is a partial IO. We need to read the full page * before to write the changes. */ uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!uncmem) { pr_info("Error allocating temp memory!\n"); ret = -ENOMEM; goto out; } ret = zram_decompress_page(zram, uncmem, index); if (ret) goto out; } /* * System overwrites unused sectors. Free memory associated * with this sector now. */ if (zram->table[index].handle || zram_test_flag(zram, index, ZRAM_ZERO)) zram_free_page(zram, index); user_mem = kmap_atomic(page); if (is_partial_io(bvec)) { memcpy(uncmem + offset, user_mem + bvec->bv_offset, bvec->bv_len); kunmap_atomic(user_mem); user_mem = NULL; } else { uncmem = user_mem; } if (page_zero_filled(uncmem)) { if (!is_partial_io(bvec)) kunmap_atomic(user_mem); zram_stat_inc(&zram->stats.pages_zero); zram_set_flag(zram, index, ZRAM_ZERO); ret = 0; goto out; } ret = zram_comp_op(ZRAM_COMPOP_COMPRESS, uncmem, PAGE_SIZE, src, &clen); if (!is_partial_io(bvec)) { kunmap_atomic(user_mem); user_mem = NULL; uncmem = NULL; } if (unlikely(ret != 0)) { pr_err("Compression failed! err=%d\n", ret); goto out; } if (unlikely(clen > max_zpage_size)) { zram_stat_inc(&zram->stats.bad_compress); clen = PAGE_SIZE; src = NULL; if (is_partial_io(bvec)) src = uncmem; } handle = zs_malloc(zram->mem_pool, clen); if (!handle) { pr_info("Error allocating memory for compressed " "page: %u, size=%zu\n", index, clen); ret = -ENOMEM; goto out; } cmem = zs_map_object(zram->mem_pool, handle, ZS_MM_WO); if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) src = kmap_atomic(page); memcpy(cmem, src, clen); if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) kunmap_atomic(src); zs_unmap_object(zram->mem_pool, handle); zram->table[index].handle = handle; zram->table[index].size = clen; /* Update stats */ zram_stat64_add(zram, &zram->stats.compr_size, clen); zram_stat_inc(&zram->stats.pages_stored); if (clen <= PAGE_SIZE / 2) zram_stat_inc(&zram->stats.good_compress); out: if (is_partial_io(bvec)) kfree(uncmem); if (ret) zram_stat64_inc(zram, &zram->stats.failed_writes); return ret; }