diff options
Diffstat (limited to 'drivers/staging/zram/zram_drv.c')
-rw-r--r-- | drivers/staging/zram/zram_drv.c | 152 |
1 files changed, 72 insertions, 80 deletions
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 6edefde23722..f2a73bd739fb 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -183,62 +183,25 @@ static inline int is_partial_io(struct bio_vec *bvec) return bvec->bv_len != PAGE_SIZE; } -static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, - u32 index, int offset, struct bio *bio) +static int zram_decompress_page(struct zram *zram, char *mem, u32 index) { - int ret; - size_t clen; - struct page *page; - unsigned char *user_mem, *cmem, *uncmem = NULL; - - page = bvec->bv_page; - - if (zram_test_flag(zram, index, ZRAM_ZERO)) { - handle_zero_page(bvec); - return 0; - } + int ret = LZO_E_OK; + size_t clen = PAGE_SIZE; + unsigned char *cmem; + unsigned long handle = zram->table[index].handle; - /* Requested page is not present in compressed area */ - if (unlikely(!zram->table[index].handle)) { - pr_debug("Read before write: sector=%lu, size=%u", - (ulong)(bio->bi_sector), bio->bi_size); - handle_zero_page(bvec); + if (!handle || zram_test_flag(zram, index, ZRAM_ZERO)) { + memset(mem, 0, PAGE_SIZE); return 0; } - if (is_partial_io(bvec)) { - /* Use a temporary buffer to decompress the page */ - uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (!uncmem) { - pr_info("Error allocating temp memory!\n"); - return -ENOMEM; - } - } - - user_mem = kmap_atomic(page); - if (!is_partial_io(bvec)) - uncmem = user_mem; - clen = PAGE_SIZE; - - cmem = zs_map_object(zram->mem_pool, zram->table[index].handle, - ZS_MM_RO); - - if (zram->table[index].size == PAGE_SIZE) { - memcpy(uncmem, cmem, PAGE_SIZE); - ret = LZO_E_OK; - } else { + cmem = zs_map_object(zram->mem_pool, handle, ZS_MM_RO); + if (zram->table[index].size == PAGE_SIZE) + memcpy(mem, cmem, PAGE_SIZE); + else ret = lzo1x_decompress_safe(cmem, zram->table[index].size, - uncmem, &clen); - } - - if (is_partial_io(bvec)) { - memcpy(user_mem + bvec->bv_offset, uncmem + offset, - bvec->bv_len); - kfree(uncmem); - } - - zs_unmap_object(zram->mem_pool, zram->table[index].handle); - kunmap_atomic(user_mem); + mem, &clen); + zs_unmap_object(zram->mem_pool, handle); /* Should NEVER happen. Return bio error if it does. */ if (unlikely(ret != LZO_E_OK)) { @@ -247,42 +210,62 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, return ret; } - flush_dcache_page(page); - return 0; } -static int zram_read_before_write(struct zram *zram, char *mem, u32 index) +static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, + u32 index, int offset, struct bio *bio) { int ret; - size_t clen = PAGE_SIZE; - unsigned char *cmem; - unsigned long handle = zram->table[index].handle; + struct page *page; + unsigned char *user_mem, *uncmem = NULL; - if (zram_test_flag(zram, index, ZRAM_ZERO) || !handle) { - memset(mem, 0, PAGE_SIZE); + page = bvec->bv_page; + + if (unlikely(!zram->table[index].handle) || + zram_test_flag(zram, index, ZRAM_ZERO)) { + handle_zero_page(bvec); return 0; } - cmem = zs_map_object(zram->mem_pool, handle, ZS_MM_RO); - ret = lzo1x_decompress_safe(cmem, zram->table[index].size, - mem, &clen); - zs_unmap_object(zram->mem_pool, handle); + user_mem = kmap_atomic(page); + if (is_partial_io(bvec)) + /* Use a temporary buffer to decompress the page */ + uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); + else + uncmem = user_mem; + + if (!uncmem) { + pr_info("Unable to allocate temp memory\n"); + ret = -ENOMEM; + goto out_cleanup; + } + ret = zram_decompress_page(zram, uncmem, index); /* Should NEVER happen. Return bio error if it does. */ if (unlikely(ret != LZO_E_OK)) { pr_err("Decompression failed! err=%d, page=%u\n", ret, index); zram_stat64_inc(zram, &zram->stats.failed_reads); - return ret; + goto out_cleanup; } - return 0; + if (is_partial_io(bvec)) + memcpy(user_mem + bvec->bv_offset, uncmem + offset, + bvec->bv_len); + + flush_dcache_page(page); + ret = 0; +out_cleanup: + kunmap_atomic(user_mem); + if (is_partial_io(bvec)) + kfree(uncmem); + return ret; } static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, int offset) { - int ret; + int ret = 0; size_t clen; unsigned long handle; struct page *page; @@ -302,11 +285,9 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, ret = -ENOMEM; goto out; } - ret = zram_read_before_write(zram, uncmem, index); - if (ret) { - kfree(uncmem); + ret = zram_decompress_page(zram, uncmem, index); + if (ret) goto out; - } } /* @@ -319,16 +300,18 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, user_mem = kmap_atomic(page); - if (is_partial_io(bvec)) + if (is_partial_io(bvec)) { memcpy(uncmem + offset, user_mem + bvec->bv_offset, bvec->bv_len); - else + kunmap_atomic(user_mem); + user_mem = NULL; + } else { uncmem = user_mem; + } if (page_zero_filled(uncmem)) { - kunmap_atomic(user_mem); - if (is_partial_io(bvec)) - kfree(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; @@ -338,9 +321,11 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen, zram->compress_workmem); - kunmap_atomic(user_mem); - if (is_partial_io(bvec)) - kfree(uncmem); + if (!is_partial_io(bvec)) { + kunmap_atomic(user_mem); + user_mem = NULL; + uncmem = NULL; + } if (unlikely(ret != LZO_E_OK)) { pr_err("Compression failed! err=%d\n", ret); @@ -349,8 +334,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, if (unlikely(clen > max_zpage_size)) { zram_stat_inc(&zram->stats.bad_compress); - src = uncmem; clen = PAGE_SIZE; + src = NULL; + if (is_partial_io(bvec)) + src = uncmem; } handle = zs_malloc(zram->mem_pool, clen); @@ -362,7 +349,11 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, } 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); @@ -375,9 +366,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, if (clen <= PAGE_SIZE / 2) zram_stat_inc(&zram->stats.good_compress); - return 0; - out: + if (is_partial_io(bvec)) + kfree(uncmem); + if (ret) zram_stat64_inc(zram, &zram->stats.failed_writes); return ret; |