Merge tag 'for-6.3/dio-2023-02-16' of git://git.kernel.dk/linux

Pull legacy dio update from Jens Axboe:
 "We only have a few file systems that use the old dio code, make them
  select it rather than build it unconditionally"

* tag 'for-6.3/dio-2023-02-16' of git://git.kernel.dk/linux:
  fs: build the legacy direct I/O code conditionally
  fs: move sb_init_dio_done_wq out of direct-io.c

Author: torvalds

fs/Kconfig

@@ -18,6 +18,10 @@ config VALIDATE_FS_PARSER
 config FS_IOMAP
 	bool
 
+# old blockdev_direct_IO implementation.  Use iomap for new code instead
+config LEGACY_DIRECT_IO
+	bool
+
 if BLOCK
 
 source "fs/ext2/Kconfig"

fs/Makefile

@@ -19,13 +19,14 @@ obj-y :=	open.o read_write.o file_table.o super.o \
 		kernel_read_file.o mnt_idmapping.o remap_range.o
 
 ifeq ($(CONFIG_BLOCK),y)
-obj-y +=	buffer.o direct-io.o mpage.o
+obj-y +=	buffer.o mpage.o
 else
 obj-y +=	no-block.o
 endif
 
 obj-$(CONFIG_PROC_FS) += proc_namespace.o
 
+obj-$(CONFIG_LEGACY_DIRECT_IO)	+= direct-io.o
 obj-y				+= notify/
 obj-$(CONFIG_EPOLL)		+= eventpoll.o
 obj-y				+= anon_inodes.o

fs/affs/Kconfig

@@ -2,6 +2,7 @@
 config AFFS_FS
 	tristate "Amiga FFS file system support"
 	depends on BLOCK
+	select LEGACY_DIRECT_IO
 	help
 	  The Fast File System (FFS) is the common file system used on hard
 	  disks by Amiga(tm) systems since AmigaOS Version 1.3 (34.20).  Say Y

fs/direct-io.c

@@ -558,30 +558,6 @@ static inline int dio_bio_reap(struct dio *dio, struct dio_submit *sdio)
 	return ret;
 }
 
-/*
- * Create workqueue for deferred direct IO completions. We allocate the
- * workqueue when it's first needed. This avoids creating workqueue for
- * filesystems that don't need it and also allows us to create the workqueue
- * late enough so the we can include s_id in the name of the workqueue.
- */
-int sb_init_dio_done_wq(struct super_block *sb)
-{
-	struct workqueue_struct *old;
-	struct workqueue_struct *wq = alloc_workqueue("dio/%s",
-						      WQ_MEM_RECLAIM, 0,
-						      sb->s_id);
-	if (!wq)
-		return -ENOMEM;
-	/*
-	 * This has to be atomic as more DIOs can race to create the workqueue
-	 */
-	old = cmpxchg(&sb->s_dio_done_wq, NULL, wq);
-	/* Someone created workqueue before us? Free ours... */
-	if (old)
-		destroy_workqueue(wq);
-	return 0;
-}
-
 static int dio_set_defer_completion(struct dio *dio)
 {
 	struct super_block *sb = dio->inode->i_sb;

fs/exfat/Kconfig

@@ -3,6 +3,7 @@
 config EXFAT_FS
 	tristate "exFAT filesystem support"
 	select NLS
+	select LEGACY_DIRECT_IO
 	help
 	  This allows you to mount devices formatted with the exFAT file system.
 	  exFAT is typically used on SD-Cards or USB sticks.

fs/ext2/Kconfig

@@ -2,6 +2,7 @@
 config EXT2_FS
 	tristate "Second extended fs support"
 	select FS_IOMAP
+	select LEGACY_DIRECT_IO
 	help
 	  Ext2 is a standard Linux file system for hard disks.
 

fs/fat/Kconfig

@@ -2,6 +2,7 @@
 config FAT_FS
 	tristate
 	select NLS
+	select LEGACY_DIRECT_IO
 	help
 	  If you want to use one of the FAT-based file systems (the MS-DOS and
 	  VFAT (Windows 95) file systems), then you must say Y or M here

fs/hfs/Kconfig

@@ -3,6 +3,7 @@ config HFS_FS
 	tristate "Apple Macintosh file system support"
 	depends on BLOCK
 	select NLS
+	select LEGACY_DIRECT_IO
 	help
 	  If you say Y here, you will be able to mount Macintosh-formatted
 	  floppy disks and hard drive partitions with full read-write access.

fs/hfsplus/Kconfig

@@ -4,6 +4,7 @@ config HFSPLUS_FS
 	depends on BLOCK
 	select NLS
 	select NLS_UTF8
+	select LEGACY_DIRECT_IO
 	help
 	  If you say Y here, you will be able to mount extended format
 	  Macintosh-formatted hard drive partitions with full read-write access.

fs/internal.h

@@ -120,6 +120,7 @@ extern bool trylock_super(struct super_block *sb);
 struct super_block *user_get_super(dev_t, bool excl);
 void put_super(struct super_block *sb);
 extern bool mount_capable(struct fs_context *);
+int sb_init_dio_done_wq(struct super_block *sb);
 
 /*
  * open.c
@@ -187,9 +188,6 @@ extern void mnt_pin_kill(struct mount *m);
  */
 extern const struct dentry_operations ns_dentry_operations;
 
-/* direct-io.c: */
-int sb_init_dio_done_wq(struct super_block *sb);
-
 /*
  * fs/stat.c:
  */