fs/fuse/control.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
I see no reason to set the private_data on the file to this value. Just
grab the result of the atomic_read() and output it without setting
private_data.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/fuse/control.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/fs/fuse/control.c b/fs/fuse/control.c
index 2a730d88cc3bdb50ea1f8a3185faad5f05fc6e74..17ef07cf0c38e44bd7eadb3450bd53a8acc5e885 100644
--- a/fs/fuse/control.c
+++ b/fs/fuse/control.c
@@ -49,18 +49,17 @@ static ssize_t fuse_conn_waiting_read(struct file *file, char __user *buf,
{
char tmp[32];
size_t size;
+ int value;
if (!*ppos) {
- long value;
struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
if (!fc)
return 0;
value = atomic_read(&fc->num_waiting);
- file->private_data = (void *)value;
fuse_conn_put(fc);
}
- size = sprintf(tmp, "%ld\n", (long)file->private_data);
+ size = sprintf(tmp, "%d\n", value);
return simple_read_from_buffer(buf, len, ppos, tmp, size);
}
---
base-commit: 9afd7336f3acbe5678cca3b3bc5baefb51ce9564
change-id: 20250204-fuse-fixes-03882c05c1b1
Best regards,
--
Jeff Layton <jlayton@kernel.org>On Tue, 4 Feb 2025 at 16:04, Jeff Layton <jlayton@kernel.org> wrote:
>
> I see no reason to set the private_data on the file to this value. Just
> grab the result of the atomic_read() and output it without setting
> private_data.
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> fs/fuse/control.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/fs/fuse/control.c b/fs/fuse/control.c
> index 2a730d88cc3bdb50ea1f8a3185faad5f05fc6e74..17ef07cf0c38e44bd7eadb3450bd53a8acc5e885 100644
> --- a/fs/fuse/control.c
> +++ b/fs/fuse/control.c
> @@ -49,18 +49,17 @@ static ssize_t fuse_conn_waiting_read(struct file *file, char __user *buf,
> {
> char tmp[32];
> size_t size;
> + int value;
>
> if (!*ppos) {
> - long value;
> struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
> if (!fc)
> return 0;
>
> value = atomic_read(&fc->num_waiting);
> - file->private_data = (void *)value;
> fuse_conn_put(fc);
> }
"value" is uninitialized if *ppos is non-zero.
I also wonder why this patch is an improvement (with the bug fixed)?
Thanks,
Mikos
On Fri, 2025-02-14 at 11:17 +0100, Miklos Szeredi wrote:
> On Tue, 4 Feb 2025 at 16:04, Jeff Layton <jlayton@kernel.org> wrote:
> >
> > I see no reason to set the private_data on the file to this value. Just
> > grab the result of the atomic_read() and output it without setting
> > private_data.
> >
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> > fs/fuse/control.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/fuse/control.c b/fs/fuse/control.c
> > index 2a730d88cc3bdb50ea1f8a3185faad5f05fc6e74..17ef07cf0c38e44bd7eadb3450bd53a8acc5e885 100644
> > --- a/fs/fuse/control.c
> > +++ b/fs/fuse/control.c
> > @@ -49,18 +49,17 @@ static ssize_t fuse_conn_waiting_read(struct file *file, char __user *buf,
> > {
> > char tmp[32];
> > size_t size;
> > + int value;
> >
> > if (!*ppos) {
> > - long value;
> > struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
> > if (!fc)
> > return 0;
> >
> > value = atomic_read(&fc->num_waiting);
> > - file->private_data = (void *)value;
> > fuse_conn_put(fc);
> > }
>
> "value" is uninitialized if *ppos is non-zero.
>
Good catch. Thanks. Do you want me to resend?
> I also wonder why this patch is an improvement (with the bug fixed)?
>
It's just an unnecessary assignment. Nothing will look at or use
private_data in this codepath, so there is no need to set it.
--
Jeff Layton <jlayton@kernel.org>
On Fri, 14 Feb 2025 at 13:58, Jeff Layton <jlayton@kernel.org> wrote: > It's just an unnecessary assignment. Nothing will look at or use > private_data in this codepath, so there is no need to set it. I think the reason it was done this way is to return a sane value even in the case of small reads (i.e. char-by-char). It's unlikely to matter in real life, but removing it is not a big enough win to be worth risking it. Thanks, Miklos
On Tue, Feb 4, 2025 at 7:09 AM Jeff Layton <jlayton@kernel.org> wrote:
>
> I see no reason to set the private_data on the file to this value. Just
> grab the result of the atomic_read() and output it without setting
> private_data.
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
> ---
> fs/fuse/control.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/fs/fuse/control.c b/fs/fuse/control.c
> index 2a730d88cc3bdb50ea1f8a3185faad5f05fc6e74..17ef07cf0c38e44bd7eadb3450bd53a8acc5e885 100644
> --- a/fs/fuse/control.c
> +++ b/fs/fuse/control.c
> @@ -49,18 +49,17 @@ static ssize_t fuse_conn_waiting_read(struct file *file, char __user *buf,
> {
> char tmp[32];
> size_t size;
> + int value;
>
It might be helpful if a "if (*ppos) return -EINVAL;" check gets added here too?
> if (!*ppos) {
> - long value;
> struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
> if (!fc)
> return 0;
>
> value = atomic_read(&fc->num_waiting);
> - file->private_data = (void *)value;
> fuse_conn_put(fc);
> }
> - size = sprintf(tmp, "%ld\n", (long)file->private_data);
> + size = sprintf(tmp, "%d\n", value);
> return simple_read_from_buffer(buf, len, ppos, tmp, size);
> }
>
>
> ---
> base-commit: 9afd7336f3acbe5678cca3b3bc5baefb51ce9564
> change-id: 20250204-fuse-fixes-03882c05c1b1
>
> Best regards,
> --
> Jeff Layton <jlayton@kernel.org>
>
>
> if (!*ppos) {
> - long value;
> struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
> if (!fc)
> return 0;
>
> value = atomic_read(&fc->num_waiting);
> - file->private_data = (void *)value;
> fuse_conn_put(fc);
> }
> - size = sprintf(tmp, "%ld\n", (long)file->private_data);
> + size = sprintf(tmp, "%d\n", value);
> return simple_read_from_buffer(buf, len, ppos, tmp, size);
> }
>
>
> ---
> base-commit: 9afd7336f3acbe5678cca3b3bc5baefb51ce9564
> change-id: 20250204-fuse-fixes-03882c05c1b1
>
> Best regards,
> --
> Jeff Layton <jlayton@kernel.org>
>
>
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