linux-kernel - [PATCH 01/12] btrfs: add helpers for compression type and level

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Date:   Mon,  4 Feb 2019 15:19:57 -0500
From:   Dennis Zhou <dennis@...nel.org>
To:     David Sterba <dsterba@...e.com>,
        Josef Bacik <josef@...icpanda.com>, Chris Mason <clm@...com>,
        Omar Sandoval <osandov@...ndov.com>,
        Nick Terrell <terrelln@...com>,
        Nikolay Borisov <nborisov@...e.com>
Cc:     kernel-team@...com, linux-btrfs@...r.kernel.org,
        linux-kernel@...r.kernel.org, Dennis Zhou <dennis@...nel.org>
Subject: [PATCH 01/12] btrfs: add helpers for compression type and level

It is very easy to miss places that rely on a certain bitshifting for
decyphering the type_level overloading. Add helpers to do this instead.

Signed-off-by: Dennis Zhou <dennis@...nel.org>
Reviewed-by: Nikolay Borisov <nborisov@...e.com>
Reviewed-by: Josef Bacik <josef@...icpanda.com>
Cc: Omar Sandoval <osandov@...ndov.com>
---
 fs/btrfs/compression.c |  2 +-
 fs/btrfs/compression.h | 10 ++++++++++
 fs/btrfs/zlib.c        |  2 +-
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 548057630b69..94a0b0a3a301 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -1036,9 +1036,9 @@ int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
 			 unsigned long *total_in,
 			 unsigned long *total_out)
 {
+	int type = btrfs_compress_type(type_level);
 	struct list_head *workspace;
 	int ret;
-	int type = type_level & 0xF;
 
 	workspace = find_workspace(type);
 
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index ddda9b80bf20..004db0b3111b 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -64,6 +64,16 @@ struct compressed_bio {
 	u32 sums;
 };
 
+static inline unsigned int btrfs_compress_type(unsigned int type_level)
+{
+	return (type_level & 0xF);
+}
+
+static inline unsigned int btrfs_compress_level(unsigned int type_level)
+{
+	return ((type_level & 0xF0) >> 4);
+}
+
 void __init btrfs_init_compress(void);
 void __cold btrfs_exit_compress(void);
 
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index 970ff3e35bb3..2bd655c4f8b4 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -393,7 +393,7 @@ static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 static void zlib_set_level(struct list_head *ws, unsigned int type)
 {
 	struct workspace *workspace = list_entry(ws, struct workspace, list);
-	unsigned level = (type & 0xF0) >> 4;
+	unsigned int level = btrfs_compress_level(type);
 
 	if (level > 9)
 		level = 9;
-- 
2.17.1