[PATCH v4 02/15] fs: Move enum rw_hint into a new header file

Bart Van Assche
2023-11-14T21:42:12Z

Move enum rw_hint into a new header file to prepare for using this data
type in the block layer. Add the attribute __packed to reduce the space
occupied by instances of this data type from four bytes to one byte.
Change the data type of i_write_hint from u8 into enum rw_hint. Change
the RWH_* constants into literal constants to prevent that
<uapi/linux/fcntl.h> would have to be included.

Cc: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
fs/f2fs/f2fs.h | 1 +
fs/fcntl.c | 1 +
fs/inode.c | 1 +
include/linux/fs.h | 16 ++--------------
include/linux/rw_hint.h | 20 ++++++++++++++++++++
5 files changed, 25 insertions(+), 14 deletions(-)
create mode 100644 include/linux/rw_hint.h

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9043cedfa12b..8e0c66a6b097 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -24,6 +24,7 @@
#include <linux/blkdev.h>
#include <linux/quotaops.h>
#include <linux/part_stat.h>
+#include <linux/rw_hint.h>
#include <crypto/hash.h>

#include <linux/fscrypt.h>
diff --git a/fs/fcntl.c b/fs/fcntl.c
index c80a6acad742..880828e14420 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -27,6 +27,7 @@
#include <linux/memfd.h>
#include <linux/compat.h>
#include <linux/mount.h>
+#include <linux/rw_hint.h>

#include <linux/poll.h>
#include <asm/siginfo.h>
diff --git a/fs/inode.c b/fs/inode.c
index 7965d5e07012..e9ae2199d67b 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -20,6 +20,7 @@
#include <linux/ratelimit.h>
#include <linux/list_lru.h>
#include <linux/iversion.h>
+#include <linux/rw_hint.h>
#include <trace/events/writeback.h>
#include "internal.h"

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 59f9de9df0fe..a08014b68d6e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -43,6 +43,7 @@
#include <linux/cred.h>
#include <linux/mnt_idmapping.h>
#include <linux/slab.h>
+#include <linux/rw_hint.h>

#include <asm/byteorder.h>
#include <uapi/linux/fs.h>
@@ -309,19 +310,6 @@ struct address_space;
struct writeback_control;
struct readahead_control;

-/*
- * Write life time hint values.
- * Stored in struct inode as u8.
- */
-enum rw_hint {
- WRITE_LIFE_0 = 0,
- WRITE_LIFE_1 = RWH_WRITE_LIFE_NONE,
- WRITE_LIFE_2 = RWH_WRITE_LIFE_SHORT,
- WRITE_LIFE_3 = RWH_WRITE_LIFE_MEDIUM,
- WRITE_LIFE_4 = RWH_WRITE_LIFE_LONG,
- WRITE_LIFE_5 = RWH_WRITE_LIFE_EXTREME,
-};
-
/* Match RWF_* bits to IOCB bits */
#define IOCB_HIPRI (__force int) RWF_HIPRI
#define IOCB_DSYNC (__force int) RWF_DSYNC
@@ -677,7 +665,7 @@ struct inode {
spinlock_t i_lock; /* i_blocks, i_bytes, maybe i_size */
unsigned short i_bytes;
u8 i_blkbits;
- u8 i_write_hint;
+ enum rw_hint i_write_hint;
blkcnt_t i_blocks;

#ifdef __NEED_I_SIZE_ORDERED
diff --git a/include/linux/rw_hint.h b/include/linux/rw_hint.h
new file mode 100644
index 000000000000..f172efb09655
--- /dev/null
+++ b/include/linux/rw_hint.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_RW_HINT_H
+#define _LINUX_RW_HINT_H
+
+#include <linux/build_bug.h>
+#include <linux/compiler_attributes.h>
+
+/* Block storage write lifetime hint values. */
+enum rw_hint {
+ WRITE_LIFE_0 = 0, /* RWH_WRITE_LIFE_NOT_SET */
+ WRITE_LIFE_1 = 1, /* RWH_WRITE_LIFE_NONE */
+ WRITE_LIFE_2 = 2, /* RWH_WRITE_LIFE_SHORT */
+ WRITE_LIFE_3 = 3, /* RWH_WRITE_LIFE_MEDIUM */
+ WRITE_LIFE_4 = 4, /* RWH_WRITE_LIFE_LONG */
+ WRITE_LIFE_5 = 5, /* RWH_WRITE_LIFE_EXTREME */
+} __packed;
+
+static_assert(sizeof(enum rw_hint) == 1);
+
+#endif /* _LINUX_RW_HINT_H */