2022-06-29 13:25:21

by Jason A. Donenfeld

Subject: [PATCH v3 5/7] fs: remove no_llseek

Now that all callers of ->llseek are going through vfs_llseek(), we
don't gain anything by keeping no_llseek around. Nothing compares it or
calls it.

Signed-off-by: Jason A. Donenfeld <[email protected]>
---
fs/read_write.c | 17 +++--------------
include/linux/fs.h | 1 -
2 files changed, 3 insertions(+), 15 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index b1b1cdfee9d3..69cd8d72d91e 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -227,12 +227,6 @@ loff_t noop_llseek(struct file *file, loff_t offset, int whence)
}
EXPORT_SYMBOL(noop_llseek);

-loff_t no_llseek(struct file *file, loff_t offset, int whence)
-{
- return -ESPIPE;
-}
-EXPORT_SYMBOL(no_llseek);
-
loff_t default_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file_inode(file);
@@ -290,14 +284,9 @@ EXPORT_SYMBOL(default_llseek);

loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
{
- loff_t (*fn)(struct file *, loff_t, int);
-
- fn = no_llseek;
- if (file->f_mode & FMODE_LSEEK) {
- if (file->f_op->llseek)
- fn = file->f_op->llseek;
- }
- return fn(file, offset, whence);
+ if (!(file->f_mode & FMODE_LSEEK) || !file->f_op->llseek)
+ return -ESPIPE;
+ return file->f_op->llseek(file, offset, whence);
}
EXPORT_SYMBOL(vfs_llseek);

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9ad5e3520fae..0cb5a1706e1f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3022,7 +3022,6 @@ extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
extern void
file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
-extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
--
2.35.1

2022-06-30 06:59:54

by Nikolay Borisov

Subject: Re: [PATCH v3 5/7] fs: remove no_llseek

On 29.06.22 г. 16:07 ч., Jason A. Donenfeld wrote:
> Now that all callers of ->llseek are going through vfs_llseek(), we
> don't gain anything by keeping no_llseek around. Nothing compares it or
> calls it.
>
> Signed-off-by: Jason A. Donenfeld <[email protected]>
> ---
> fs/read_write.c | 17 +++--------------
> include/linux/fs.h | 1 -
> 2 files changed, 3 insertions(+), 15 deletions(-)
>
> diff --git a/fs/read_write.c b/fs/read_write.c
> index b1b1cdfee9d3..69cd8d72d91e 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -227,12 +227,6 @@ loff_t noop_llseek(struct file *file, loff_t offset, int whence)
> }
> EXPORT_SYMBOL(noop_llseek);
>
> -loff_t no_llseek(struct file *file, loff_t offset, int whence)
> -{
> - return -ESPIPE;
> -}
> -EXPORT_SYMBOL(no_llseek);
> -
> loff_t default_llseek(struct file *file, loff_t offset, int whence)
> {
> struct inode *inode = file_inode(file);
> @@ -290,14 +284,9 @@ EXPORT_SYMBOL(default_llseek);
>
> loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
> {
> - loff_t (*fn)(struct file *, loff_t, int);
> -
> - fn = no_llseek;
> - if (file->f_mode & FMODE_LSEEK) {
> - if (file->f_op->llseek)
> - fn = file->f_op->llseek;
> - }
> - return fn(file, offset, whence);
> + if (!(file->f_mode & FMODE_LSEEK) || !file->f_op->llseek)

Is it not sufficient here to just check for the presence of FMODE_LSEEK?
NULL llseek shall result in FMODE_LSEEK not being set when the file is
opened?

> + return -ESPIPE;
> + return file->f_op->llseek(file, offset, whence);
> }
> EXPORT_SYMBOL(vfs_llseek);
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 9ad5e3520fae..0cb5a1706e1f 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3022,7 +3022,6 @@ extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
> extern void
> file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
> extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
> -extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
> extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
> extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
> extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,

2022-06-30 14:46:00

by Jason A. Donenfeld

Subject: Re: [PATCH v3 5/7] fs: remove no_llseek

Hi Nikolay,

On Thu, Jun 30, 2022 at 09:45:04AM +0300, Nikolay Borisov wrote:
>
>
> On 29.06.22 г. 16:07 ч., Jason A. Donenfeld wrote:
> > Now that all callers of ->llseek are going through vfs_llseek(), we
> > don't gain anything by keeping no_llseek around. Nothing compares it or
> > calls it.
> >
> > Signed-off-by: Jason A. Donenfeld <[email protected]>
> > ---
> > fs/read_write.c | 17 +++--------------
> > include/linux/fs.h | 1 -
> > 2 files changed, 3 insertions(+), 15 deletions(-)
> >
> > diff --git a/fs/read_write.c b/fs/read_write.c
> > index b1b1cdfee9d3..69cd8d72d91e 100644
> > --- a/fs/read_write.c
> > +++ b/fs/read_write.c
> > @@ -227,12 +227,6 @@ loff_t noop_llseek(struct file *file, loff_t offset, int whence)
> > }
> > EXPORT_SYMBOL(noop_llseek);
> >
> > -loff_t no_llseek(struct file *file, loff_t offset, int whence)
> > -{
> > - return -ESPIPE;
> > -}
> > -EXPORT_SYMBOL(no_llseek);
> > -
> > loff_t default_llseek(struct file *file, loff_t offset, int whence)
> > {
> > struct inode *inode = file_inode(file);
> > @@ -290,14 +284,9 @@ EXPORT_SYMBOL(default_llseek);
> >
> > loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
> > {
> > - loff_t (*fn)(struct file *, loff_t, int);
> > -
> > - fn = no_llseek;
> > - if (file->f_mode & FMODE_LSEEK) {
> > - if (file->f_op->llseek)
> > - fn = file->f_op->llseek;
> > - }
> > - return fn(file, offset, whence);
> > + if (!(file->f_mode & FMODE_LSEEK) || !file->f_op->llseek)
>
> Is it not sufficient here to just check for the presence of FMODE_LSEEK?
> NULL llseek shall result in FMODE_LSEEK not being set when the file is
> opened?

Yes, that's probably fine. I did this out of an abundance of caution,
but I have a feeling Al might agree with you that useless is useless. I
can send a v4 changing that.

Al, what do you think?

Jason