[PATCH AUTOSEL 5.8 003/132] f2fs: allocate proper size memory for zstd decompress

Sasha Levin
2020-10-27T00:34:28Z

From: Chao Yu <yuchao0@huawei.com>

[ Upstream commit 0e2b7385cb59e566520cfd0a04b4b53bc9461e98 ]

As 5kft <5kft@5kft.org> reported:

kworker/u9:3: page allocation failure: order:9, mode:0x40c40(GFP_NOFS|__GFP_COMP), nodemask=(null),cpuset=/,mems_allowed=0
CPU: 3 PID: 8168 Comm: kworker/u9:3 Tainted: G C 5.8.3-sunxi #trunk
Hardware name: Allwinner sun8i Family
Workqueue: f2fs_post_read_wq f2fs_post_read_work
[<c010d6d5>] (unwind_backtrace) from [<c0109a55>] (show_stack+0x11/0x14)
[<c0109a55>] (show_stack) from [<c056d489>] (dump_stack+0x75/0x84)
[<c056d489>] (dump_stack) from [<c0243b53>] (warn_alloc+0xa3/0x104)
[<c0243b53>] (warn_alloc) from [<c024473b>] (__alloc_pages_nodemask+0xb87/0xc40)
[<c024473b>] (__alloc_pages_nodemask) from [<c02267c5>] (kmalloc_order+0x19/0x38)
[<c02267c5>] (kmalloc_order) from [<c02267fd>] (kmalloc_order_trace+0x19/0x90)
[<c02267fd>] (kmalloc_order_trace) from [<c047c665>] (zstd_init_decompress_ctx+0x21/0x88)
[<c047c665>] (zstd_init_decompress_ctx) from [<c047e9cf>] (f2fs_decompress_pages+0x97/0x228)
[<c047e9cf>] (f2fs_decompress_pages) from [<c045d0ab>] (__read_end_io+0xfb/0x130)
[<c045d0ab>] (__read_end_io) from [<c045d141>] (f2fs_post_read_work+0x61/0x84)
[<c045d141>] (f2fs_post_read_work) from [<c0130b2f>] (process_one_work+0x15f/0x3b0)
[<c0130b2f>] (process_one_work) from [<c0130e7b>] (worker_thread+0xfb/0x3e0)
[<c0130e7b>] (worker_thread) from [<c0135c3b>] (kthread+0xeb/0x10c)
[<c0135c3b>] (kthread) from [<c0100159>]

zstd may allocate large size memory for {,de}compression, it may cause
file copy failure on low-end device which has very few memory.

For decompression, let's just allocate proper size memory based on current
file's cluster size instead of max cluster size.

Reported-by: 5kft <5kft@5kft.org>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/compress.c | 7 ++++---
fs/f2fs/f2fs.h | 2 +-
2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 2390f7943f6c8..47b62099533bd 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -375,16 +375,17 @@ static int zstd_init_decompress_ctx(struct decompress_io_ctx *dic)
ZSTD_DStream *stream;
void *workspace;
unsigned int workspace_size;
+ unsigned int max_window_size =
+ MAX_COMPRESS_WINDOW_SIZE(dic->log_cluster_size);

- workspace_size = ZSTD_DStreamWorkspaceBound(MAX_COMPRESS_WINDOW_SIZE);
+ workspace_size = ZSTD_DStreamWorkspaceBound(max_window_size);

workspace = f2fs_kvmalloc(F2FS_I_SB(dic->inode),
workspace_size, GFP_NOFS);
if (!workspace)
return -ENOMEM;

- stream = ZSTD_initDStream(MAX_COMPRESS_WINDOW_SIZE,
- workspace, workspace_size);
+ stream = ZSTD_initDStream(max_window_size, workspace, workspace_size);
if (!stream) {
printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_initDStream failed\n",
KERN_ERR, F2FS_I_SB(dic->inode)->sb->s_id,
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 7d9afd54e9d8f..f03c573e427a5 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1392,7 +1392,7 @@ struct decompress_io_ctx {
#define NULL_CLUSTER ((unsigned int)(~0))
#define MIN_COMPRESS_LOG_SIZE 2
#define MAX_COMPRESS_LOG_SIZE 8
-#define MAX_COMPRESS_WINDOW_SIZE ((PAGE_SIZE) << MAX_COMPRESS_LOG_SIZE)
+#define MAX_COMPRESS_WINDOW_SIZE(log_size) ((PAGE_SIZE) << (log_size))

struct f2fs_sb_info {
struct super_block *sb; /* pointer to VFS super block */
--
2.25.1