diff options
Diffstat (limited to 'drivers/block/zram/zram_drv.c')
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 41 |
1 files changed, 29 insertions, 12 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 7436b2d27fa3..a1d6b5597c17 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -298,7 +298,8 @@ static void reset_bdev(struct zram *zram) zram->backing_dev = NULL; zram->old_block_size = 0; zram->bdev = NULL; - + zram->disk->queue->backing_dev_info->capabilities |= + BDI_CAP_SYNCHRONOUS_IO; kvfree(zram->bitmap); zram->bitmap = NULL; } @@ -336,6 +337,7 @@ static ssize_t backing_dev_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { char *file_name; + size_t sz; struct file *backing_dev = NULL; struct inode *inode; struct address_space *mapping; @@ -356,7 +358,11 @@ static ssize_t backing_dev_store(struct device *dev, goto out; } - strlcpy(file_name, buf, len); + strlcpy(file_name, buf, PATH_MAX); + /* ignore trailing newline */ + sz = strlen(file_name); + if (sz > 0 && file_name[sz - 1] == '\n') + file_name[sz - 1] = 0x00; backing_dev = filp_open(file_name, O_RDWR|O_LARGEFILE, 0); if (IS_ERR(backing_dev)) { @@ -400,6 +406,18 @@ static ssize_t backing_dev_store(struct device *dev, zram->backing_dev = backing_dev; zram->bitmap = bitmap; zram->nr_pages = nr_pages; + /* + * With writeback feature, zram does asynchronous IO so it's no longer + * synchronous device so let's remove synchronous io flag. Othewise, + * upper layer(e.g., swap) could wait IO completion rather than + * (submit and return), which will cause system sluggish. + * Furthermore, when the IO function returns(e.g., swap_readpage), + * upper layer expects IO was done so it could deallocate the page + * freely but in fact, IO is going on so finally could cause + * use-after-free when the IO is really done. + */ + zram->disk->queue->backing_dev_info->capabilities &= + ~BDI_CAP_SYNCHRONOUS_IO; up_write(&zram->init_lock); pr_info("setup backing device %s\n", file_name); @@ -1274,17 +1292,16 @@ static void zram_bio_discard(struct zram *zram, u32 index, * Returns 1 if IO request was successfully submitted. */ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, - int offset, bool is_write, struct bio *bio) + int offset, unsigned int op, struct bio *bio) { unsigned long start_time = jiffies; - int rw_acct = is_write ? REQ_OP_WRITE : REQ_OP_READ; struct request_queue *q = zram->disk->queue; int ret; - generic_start_io_acct(q, rw_acct, bvec->bv_len >> SECTOR_SHIFT, + generic_start_io_acct(q, op, bvec->bv_len >> SECTOR_SHIFT, &zram->disk->part0); - if (!is_write) { + if (!op_is_write(op)) { atomic64_inc(&zram->stats.num_reads); ret = zram_bvec_read(zram, bvec, index, offset, bio); flush_dcache_page(bvec->bv_page); @@ -1293,14 +1310,14 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, ret = zram_bvec_write(zram, bvec, index, offset, bio); } - generic_end_io_acct(q, rw_acct, &zram->disk->part0, start_time); + generic_end_io_acct(q, op, &zram->disk->part0, start_time); zram_slot_lock(zram, index); zram_accessed(zram, index); zram_slot_unlock(zram, index); if (unlikely(ret < 0)) { - if (!is_write) + if (!op_is_write(op)) atomic64_inc(&zram->stats.failed_reads); else atomic64_inc(&zram->stats.failed_writes); @@ -1338,7 +1355,7 @@ static void __zram_make_request(struct zram *zram, struct bio *bio) bv.bv_len = min_t(unsigned int, PAGE_SIZE - offset, unwritten); if (zram_bvec_rw(zram, &bv, index, offset, - op_is_write(bio_op(bio)), bio) < 0) + bio_op(bio), bio) < 0) goto out; bv.bv_offset += bv.bv_len; @@ -1390,7 +1407,7 @@ static void zram_slot_free_notify(struct block_device *bdev, } static int zram_rw_page(struct block_device *bdev, sector_t sector, - struct page *page, bool is_write) + struct page *page, unsigned int op) { int offset, ret; u32 index; @@ -1414,7 +1431,7 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector, bv.bv_len = PAGE_SIZE; bv.bv_offset = 0; - ret = zram_bvec_rw(zram, &bv, index, offset, is_write, NULL); + ret = zram_bvec_rw(zram, &bv, index, offset, op, NULL); out: /* * If I/O fails, just return error(ie, non-zero) without @@ -1429,7 +1446,7 @@ out: switch (ret) { case 0: - page_endio(page, is_write, 0); + page_endio(page, op_is_write(op), 0); break; case 1: ret = 0; |