remove write hint leftovers

remove write hint leftovers

[Christoph Hellwig]

Hi Jens,

this removes the other two fields and the two now unused fcntls
as pointed out by Dave.

[PATCH 1/2] fs: remove kiocb.ki_hint

[Christoph Hellwig]

This field is entirely unused now except for a tracepoint in f2fs, so
remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/aio.c                    |  1 -
 fs/cachefiles/io.c          |  2 --
 fs/f2fs/file.c              |  6 ------
 fs/io_uring.c               |  1 -
 include/linux/fs.h          | 12 ------------
 include/trace/events/f2fs.h |  3 +--
 6 files changed, 1 insertion(+), 24 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 4ceba13a7db0f..eb0948bb74f18 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1478,7 +1478,6 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
 	req->ki_flags = iocb_flags(req->ki_filp);
 	if (iocb->aio_flags & IOCB_FLAG_RESFD)
 		req->ki_flags |= IOCB_EVENTFD;
-	req->ki_hint = ki_hint_validate(file_write_hint(req->ki_filp));
 	if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {
 		/*
 		 * If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then
diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
index 753986ea1583b..bc7c7a7d92600 100644
--- a/fs/cachefiles/io.c
+++ b/fs/cachefiles/io.c
@@ -138,7 +138,6 @@ static int cachefiles_read(struct netfs_cache_resources *cres,
 	ki->iocb.ki_filp	= file;
 	ki->iocb.ki_pos		= start_pos + skipped;
 	ki->iocb.ki_flags	= IOCB_DIRECT;
-	ki->iocb.ki_hint	= ki_hint_validate(file_write_hint(file));
 	ki->iocb.ki_ioprio	= get_current_ioprio();
 	ki->skipped		= skipped;
 	ki->object		= object;
@@ -313,7 +312,6 @@ static int cachefiles_write(struct netfs_cache_resources *cres,
 	ki->iocb.ki_filp	= file;
 	ki->iocb.ki_pos		= start_pos;
 	ki->iocb.ki_flags	= IOCB_DIRECT | IOCB_WRITE;
-	ki->iocb.ki_hint	= ki_hint_validate(file_write_hint(file));
 	ki->iocb.ki_ioprio	= get_current_ioprio();
 	ki->object		= object;
 	ki->inval_counter	= cres->inval_counter;
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 3c98ef6af97d1..45076c01a2bab 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4479,10 +4479,8 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from,
 	struct f2fs_inode_info *fi = F2FS_I(inode);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	const bool do_opu = f2fs_lfs_mode(sbi);
-	const int whint_mode = F2FS_OPTION(sbi).whint_mode;
 	const loff_t pos = iocb->ki_pos;
 	const ssize_t count = iov_iter_count(from);
-	const enum rw_hint hint = iocb->ki_hint;
 	unsigned int dio_flags;
 	struct iomap_dio *dio;
 	ssize_t ret;
@@ -4515,8 +4513,6 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from,
 		if (do_opu)
 			down_read(&fi->i_gc_rwsem[READ]);
 	}
-	if (whint_mode == WHINT_MODE_OFF)
-		iocb->ki_hint = WRITE_LIFE_NOT_SET;
 
 	/*
 	 * We have to use __iomap_dio_rw() and iomap_dio_complete() instead of
@@ -4539,8 +4535,6 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from,
 		ret = iomap_dio_complete(dio);
 	}
 
-	if (whint_mode == WHINT_MODE_OFF)
-		iocb->ki_hint = hint;
 	if (do_opu)
 		up_read(&fi->i_gc_rwsem[READ]);
 	up_read(&fi->i_gc_rwsem[WRITE]);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 23e7f93d39563..02400fd00501e 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3790,7 +3790,6 @@ static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
 		return -EBADF;
-	req->rw.kiocb.ki_hint = ki_hint_validate(file_write_hint(req->file));
 	return io_prep_rw(req, sqe);
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e2d892b201b07..d5658ac5d8c65 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -327,7 +327,6 @@ struct kiocb {
 	void (*ki_complete)(struct kiocb *iocb, long ret);
 	void			*private;
 	int			ki_flags;
-	u16			ki_hint;
 	u16			ki_ioprio; /* See linux/ioprio.h */
 	struct wait_page_queue	*ki_waitq; /* for async buffered IO */
 	randomized_struct_fields_end
@@ -2225,21 +2224,11 @@ static inline enum rw_hint file_write_hint(struct file *file)
 
 static inline int iocb_flags(struct file *file);
 
-static inline u16 ki_hint_validate(enum rw_hint hint)
-{
-	typeof(((struct kiocb *)0)->ki_hint) max_hint = -1;
-
-	if (hint <= max_hint)
-		return hint;
-	return 0;
-}
-
 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
 {
 	*kiocb = (struct kiocb) {
 		.ki_filp = filp,
 		.ki_flags = iocb_flags(filp),
-		.ki_hint = ki_hint_validate(file_write_hint(filp)),
 		.ki_ioprio = get_current_ioprio(),
 	};
 }
@@ -2250,7 +2239,6 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
 	*kiocb = (struct kiocb) {
 		.ki_filp = filp,
 		.ki_flags = kiocb_src->ki_flags,
-		.ki_hint = kiocb_src->ki_hint,
 		.ki_ioprio = kiocb_src->ki_ioprio,
 		.ki_pos = kiocb_src->ki_pos,
 	};
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index f701bb23f83c4..1779e133cea0c 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -956,12 +956,11 @@ TRACE_EVENT(f2fs_direct_IO_enter,
 		__entry->rw	= rw;
 	),
 
-	TP_printk("dev = (%d,%d), ino = %lu pos = %lld len = %lu ki_flags = %x ki_hint = %x ki_ioprio = %x rw = %d",
+	TP_printk("dev = (%d,%d), ino = %lu pos = %lld len = %lu ki_flags = %x ki_ioprio = %x rw = %d",
 		show_dev_ino(__entry),
 		__entry->iocb->ki_pos,
 		__entry->len,
 		__entry->iocb->ki_flags,
-		__entry->iocb->ki_hint,
 		__entry->iocb->ki_ioprio,
 		__entry->rw)
 );
-- 
2.30.2

[PATCH 2/2] fs: remove fs.f_write_hint

[Christoph Hellwig]

The value is now completely unused except for reporting it back through
the F_GET_FILE_RW_HINT ioctl, so remove the value and the two ioctls
for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/fcntl.c         | 18 ------------------
 fs/open.c          |  1 -
 include/linux/fs.h |  9 ---------
 3 files changed, 28 deletions(-)

diff --git a/fs/fcntl.c b/fs/fcntl.c
index 9c6c6a3e2de51..f15d885b97961 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -291,22 +291,6 @@ static long fcntl_rw_hint(struct file *file, unsigned int cmd,
 	u64 h;
 
 	switch (cmd) {
-	case F_GET_FILE_RW_HINT:
-		h = file_write_hint(file);
-		if (copy_to_user(argp, &h, sizeof(*argp)))
-			return -EFAULT;
-		return 0;
-	case F_SET_FILE_RW_HINT:
-		if (copy_from_user(&h, argp, sizeof(h)))
-			return -EFAULT;
-		hint = (enum rw_hint) h;
-		if (!rw_hint_valid(hint))
-			return -EINVAL;
-
-		spin_lock(&file->f_lock);
-		file->f_write_hint = hint;
-		spin_unlock(&file->f_lock);
-		return 0;
 	case F_GET_RW_HINT:
 		h = inode->i_write_hint;
 		if (copy_to_user(argp, &h, sizeof(*argp)))
@@ -431,8 +415,6 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
 		break;
 	case F_GET_RW_HINT:
 	case F_SET_RW_HINT:
-	case F_GET_FILE_RW_HINT:
-	case F_SET_FILE_RW_HINT:
 		err = fcntl_rw_hint(filp, cmd, arg);
 		break;
 	default:
diff --git a/fs/open.c b/fs/open.c
index 9ff2f621b760b..1315253e02473 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -835,7 +835,6 @@ static int do_dentry_open(struct file *f,
 	     likely(f->f_op->write || f->f_op->write_iter))
 		f->f_mode |= FMODE_CAN_WRITE;
 
-	f->f_write_hint = WRITE_LIFE_NOT_SET;
 	f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 
 	file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d5658ac5d8c65..a1fc3b41cd82f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -966,7 +966,6 @@ struct file {
 	 * Must not be taken from IRQ context.
 	 */
 	spinlock_t		f_lock;
-	enum rw_hint		f_write_hint;
 	atomic_long_t		f_count;
 	unsigned int 		f_flags;
 	fmode_t			f_mode;
@@ -2214,14 +2213,6 @@ static inline bool HAS_UNMAPPED_ID(struct user_namespace *mnt_userns,
 	       !gid_valid(i_gid_into_mnt(mnt_userns, inode));
 }
 
-static inline enum rw_hint file_write_hint(struct file *file)
-{
-	if (file->f_write_hint != WRITE_LIFE_NOT_SET)
-		return file->f_write_hint;
-
-	return file_inode(file)->i_write_hint;
-}
-
 static inline int iocb_flags(struct file *file);
 
 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
-- 
2.30.2

Re: [PATCH 2/2] fs: remove fs.f_write_hint

[Jens Axboe]

On 3/7/22 3:47 AM, Christoph Hellwig wrote:
> The value is now completely unused except for reporting it back through
> the F_GET_FILE_RW_HINT ioctl, so remove the value and the two ioctls
> for it.

This commit message could do with some verbiage on why the EINVAL
solution was chosen for the F_{GET,SET}_RW_HINT ioctls.

-- 
Jens Axboe

Re: [PATCH 2/2] fs: remove fs.f_write_hint

[Al Viro]

On Mon, Mar 07, 2022 at 11:47:01AM +0100, Christoph Hellwig wrote:
> The value is now completely unused except for reporting it back through
> the F_GET_FILE_RW_HINT ioctl, so remove the value and the two ioctls
> for it.

Obvious question - which userland code issues these ioctls?  I obviously
like the series, but...

Re: [PATCH 2/2] fs: remove fs.f_write_hint

[Christoph Hellwig]

On Sun, Mar 13, 2022 at 01:05:55AM +0000, Al Viro wrote:
> On Mon, Mar 07, 2022 at 11:47:01AM +0100, Christoph Hellwig wrote:
> > The value is now completely unused except for reporting it back through
> > the F_GET_FILE_RW_HINT ioctl, so remove the value and the two ioctls
> > for it.
> 
> Obvious question - which userland code issues these ioctls?  I obviously
> like the series, but...

The only places I've ever found are fio and ceph.  Despite all the noise
about Android, the google code search for Android does not actually find
a user there.

remove write hint leftovers v2

[Christoph Hellwig]

Hi Jens,

this removes the other two fields and the two now unused fcntls
as pointed out by Dave.

Changes since v1:
 - better commit log

[PATCH 2/2] fs: remove fs.f_write_hint

[Christoph Hellwig]

The value is now completely unused except for reporting it back through
the F_GET_FILE_RW_HINT ioctl, so remove the value and the two ioctls
for it.

Trying to use the F_SET_FILE_RW_HINT and F_GET_FILE_RW_HINT fcntls will
now return EINVAL, just like it would on a kernel that never supported
this functionality in the first place.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/fcntl.c         | 18 ------------------
 fs/open.c          |  1 -
 include/linux/fs.h |  9 ---------
 3 files changed, 28 deletions(-)

diff --git a/fs/fcntl.c b/fs/fcntl.c
index 9c6c6a3e2de51..f15d885b97961 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -291,22 +291,6 @@ static long fcntl_rw_hint(struct file *file, unsigned int cmd,
 	u64 h;
 
 	switch (cmd) {
-	case F_GET_FILE_RW_HINT:
-		h = file_write_hint(file);
-		if (copy_to_user(argp, &h, sizeof(*argp)))
-			return -EFAULT;
-		return 0;
-	case F_SET_FILE_RW_HINT:
-		if (copy_from_user(&h, argp, sizeof(h)))
-			return -EFAULT;
-		hint = (enum rw_hint) h;
-		if (!rw_hint_valid(hint))
-			return -EINVAL;
-
-		spin_lock(&file->f_lock);
-		file->f_write_hint = hint;
-		spin_unlock(&file->f_lock);
-		return 0;
 	case F_GET_RW_HINT:
 		h = inode->i_write_hint;
 		if (copy_to_user(argp, &h, sizeof(*argp)))
@@ -431,8 +415,6 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
 		break;
 	case F_GET_RW_HINT:
 	case F_SET_RW_HINT:
-	case F_GET_FILE_RW_HINT:
-	case F_SET_FILE_RW_HINT:
 		err = fcntl_rw_hint(filp, cmd, arg);
 		break;
 	default:
diff --git a/fs/open.c b/fs/open.c
index 9ff2f621b760b..1315253e02473 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -835,7 +835,6 @@ static int do_dentry_open(struct file *f,
 	     likely(f->f_op->write || f->f_op->write_iter))
 		f->f_mode |= FMODE_CAN_WRITE;
 
-	f->f_write_hint = WRITE_LIFE_NOT_SET;
 	f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 
 	file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d5658ac5d8c65..a1fc3b41cd82f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -966,7 +966,6 @@ struct file {
 	 * Must not be taken from IRQ context.
 	 */
 	spinlock_t		f_lock;
-	enum rw_hint		f_write_hint;
 	atomic_long_t		f_count;
 	unsigned int 		f_flags;
 	fmode_t			f_mode;
@@ -2214,14 +2213,6 @@ static inline bool HAS_UNMAPPED_ID(struct user_namespace *mnt_userns,
 	       !gid_valid(i_gid_into_mnt(mnt_userns, inode));
 }
 
-static inline enum rw_hint file_write_hint(struct file *file)
-{
-	if (file->f_write_hint != WRITE_LIFE_NOT_SET)
-		return file->f_write_hint;
-
-	return file_inode(file)->i_write_hint;
-}
-
 static inline int iocb_flags(struct file *file);
 
 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
-- 
2.30.2

Re: [PATCH 2/2] fs: remove fs.f_write_hint

[Chaitanya Kulkarni]

On 3/7/22 22:05, Christoph Hellwig wrote:
> The value is now completely unused except for reporting it back through
> the F_GET_FILE_RW_HINT ioctl, so remove the value and the two ioctls
> for it.
> 
> Trying to use the F_SET_FILE_RW_HINT and F_GET_FILE_RW_HINT fcntls will
> now return EINVAL, just like it would on a kernel that never supported
> this functionality in the first place.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   fs/fcntl.c         | 18 ------------------

this follows the discussion on the other tread of returning EINVAL.

Looks good.

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

Re: [PATCH 2/2] fs: remove fs.f_write_hint

[Dave Chinner]

On Tue, Mar 08, 2022 at 07:05:29AM +0100, Christoph Hellwig wrote:
> The value is now completely unused except for reporting it back through
> the F_GET_FILE_RW_HINT ioctl, so remove the value and the two ioctls
> for it.
> 
> Trying to use the F_SET_FILE_RW_HINT and F_GET_FILE_RW_HINT fcntls will
> now return EINVAL, just like it would on a kernel that never supported
> this functionality in the first place.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

LGTM.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
-- 
Dave Chinner
david@fromorbit.com