2023-06-26 07:25:33

by Deepak R Varma

[permalink] [raw]
Subject: [PATCH v2] gfs2: Replace deprecated kmap_atomic() by kmap_local_page()

kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().

Therefore, replace kmap_atomic() with kmap_local_page() in
gfs2_internal_read() and stuffed_readpage().

kmap_atomic() disables page-faults and preemption (the latter only for
!PREEMPT_RT kernels), However, the code within the mapping/un-mapping in
gfs2_internal_read() and stuffed_readpage() does not depend on the
above-mentioned side effects.

Therefore, a mere replacement of the old API with the new one is all that
is required (i.e., there is no need to explicitly add any calls to
pagefault_disable() and/or preempt_disable()).

Signed-off-by: Deepak R Varma <[email protected]>
---
Note: The Patch is build tested only. I will be happy to run recommended testing
with some guidance if required.

Changes in v2:
- Update patch description to correct the replacement function name from
kmap_local_folio to kmap_local _page


fs/gfs2/aops.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 3b41542d6697..7bd92054d353 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -432,10 +432,10 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
if (error)
return error;

- kaddr = kmap_atomic(page);
+ kaddr = kmap_local_page(page);
memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
memset(kaddr + dsize, 0, PAGE_SIZE - dsize);
- kunmap_atomic(kaddr);
+ kunmap_local(kaddr);
flush_dcache_page(page);
brelse(dibh);
SetPageUptodate(page);
@@ -498,12 +498,12 @@ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
continue;
return PTR_ERR(page);
}
- p = kmap_atomic(page);
+ p = kmap_local_page(page);
amt = size - copied;
if (offset + size > PAGE_SIZE)
amt = PAGE_SIZE - offset;
memcpy(buf + copied, p + offset, amt);
- kunmap_atomic(p);
+ kunmap_local(p);
put_page(page);
copied += amt;
index++;
--
2.34.1





2023-06-27 12:15:18

by Fabio M. De Francesco

[permalink] [raw]
Subject: Re: [PATCH v2] gfs2: Replace deprecated kmap_atomic() by kmap_local_page()

On luned? 26 giugno 2023 08:51:09 CEST Deepak R Varma wrote:
> kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().
>
> Therefore, replace kmap_atomic() with kmap_local_page() in
> gfs2_internal_read() and stuffed_readpage().
>
> kmap_atomic() disables page-faults and preemption (the latter only for
> !PREEMPT_RT kernels), However, the code within the mapping/un-mapping in
> gfs2_internal_read() and stuffed_readpage() does not depend on the
> above-mentioned side effects.
>
> Therefore, a mere replacement of the old API with the new one is all that
> is required (i.e., there is no need to explicitly add any calls to
> pagefault_disable() and/or preempt_disable()).
>
> Signed-off-by: Deepak R Varma <[email protected]>
> ---
> Note: The Patch is build tested only. I will be happy to run recommended
> testing with some guidance if required.
>
> Changes in v2:
> - Update patch description to correct the replacement function name from
> kmap_local_folio to kmap_local _page

Ah, well done. I didn't note this with the comment on v1.

> fs/gfs2/aops.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
> index 3b41542d6697..7bd92054d353 100644
> --- a/fs/gfs2/aops.c
> +++ b/fs/gfs2/aops.c
> @@ -432,10 +432,10 @@ static int stuffed_readpage(struct gfs2_inode *ip,
> struct page *page) if (error)
> return error;
>
> - kaddr = kmap_atomic(page);
> + kaddr = kmap_local_page(page);
> memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
> memset(kaddr + dsize, 0, PAGE_SIZE - dsize);
> - kunmap_atomic(kaddr);
> + kunmap_local(kaddr);
> flush_dcache_page(page);
> brelse(dibh);
> SetPageUptodate(page);
> @@ -498,12 +498,12 @@ int gfs2_internal_read(struct gfs2_inode *ip, char
*buf,
> loff_t *pos, continue;
> return PTR_ERR(page);
> }
> - p = kmap_atomic(page);
> + p = kmap_local_page(page);
> amt = size - copied;
> if (offset + size > PAGE_SIZE)
> amt = PAGE_SIZE - offset;
> memcpy(buf + copied, p + offset, amt);

As said in the comment on v1, the memcpy_from_page() helper is better suited
here, unless you noted something that prevents its use and that I'm not able
to see at the moment.

Thanks,

Fabio

> - kunmap_atomic(p);
> + kunmap_local(p);
> put_page(page);
> copied += amt;
> index++;
> --
> 2.34.1





2023-06-27 14:12:32

by Andreas Gruenbacher

[permalink] [raw]
Subject: Re: [PATCH v2] gfs2: Replace deprecated kmap_atomic() by kmap_local_page()

On Mon, Jun 26, 2023 at 8:51 AM Deepak R Varma <[email protected]> wrote:
> kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().

I'll apply this, convert the remaining instances of kmap_atomic(), and
switch to memcpy_{from,to}_page() where appropriate.

Thanks,
Andreas

> Therefore, replace kmap_atomic() with kmap_local_page() in
> gfs2_internal_read() and stuffed_readpage().
>
> kmap_atomic() disables page-faults and preemption (the latter only for
> !PREEMPT_RT kernels), However, the code within the mapping/un-mapping in
> gfs2_internal_read() and stuffed_readpage() does not depend on the
> above-mentioned side effects.
>
> Therefore, a mere replacement of the old API with the new one is all that
> is required (i.e., there is no need to explicitly add any calls to
> pagefault_disable() and/or preempt_disable()).
>
> Signed-off-by: Deepak R Varma <[email protected]>
> ---
> Note: The Patch is build tested only. I will be happy to run recommended testing
> with some guidance if required.
>
> Changes in v2:
> - Update patch description to correct the replacement function name from
> kmap_local_folio to kmap_local _page
>
>
> fs/gfs2/aops.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
> index 3b41542d6697..7bd92054d353 100644
> --- a/fs/gfs2/aops.c
> +++ b/fs/gfs2/aops.c
> @@ -432,10 +432,10 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
> if (error)
> return error;
>
> - kaddr = kmap_atomic(page);
> + kaddr = kmap_local_page(page);
> memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
> memset(kaddr + dsize, 0, PAGE_SIZE - dsize);
> - kunmap_atomic(kaddr);
> + kunmap_local(kaddr);
> flush_dcache_page(page);
> brelse(dibh);
> SetPageUptodate(page);
> @@ -498,12 +498,12 @@ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
> continue;
> return PTR_ERR(page);
> }
> - p = kmap_atomic(page);
> + p = kmap_local_page(page);
> amt = size - copied;
> if (offset + size > PAGE_SIZE)
> amt = PAGE_SIZE - offset;
> memcpy(buf + copied, p + offset, amt);
> - kunmap_atomic(p);
> + kunmap_local(p);
> put_page(page);
> copied += amt;
> index++;
> --
> 2.34.1
>
>
>


2023-06-27 18:56:15

by Deepak R Varma

[permalink] [raw]
Subject: Re: [PATCH v2] gfs2: Replace deprecated kmap_atomic() by kmap_local_page()

On Tue, Jun 27, 2023 at 03:45:20PM +0200, Andreas Gruenbacher wrote:
> On Mon, Jun 26, 2023 at 8:51 AM Deepak R Varma <[email protected]> wrote:
> > kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().
>
> I'll apply this, convert the remaining instances of kmap_atomic(), and
> switch to memcpy_{from,to}_page() where appropriate.

Hello Andreas,
Thank you for your review. I am working on the other conversion opportunities
for this module and will send those in shortly.

Regards,
Deepak.

>
> Thanks,
> Andreas
>
> > Therefore, replace kmap_atomic() with kmap_local_page() in
> > gfs2_internal_read() and stuffed_readpage().
> >
> > kmap_atomic() disables page-faults and preemption (the latter only for
> > !PREEMPT_RT kernels), However, the code within the mapping/un-mapping in
> > gfs2_internal_read() and stuffed_readpage() does not depend on the
> > above-mentioned side effects.
> >
> > Therefore, a mere replacement of the old API with the new one is all that
> > is required (i.e., there is no need to explicitly add any calls to
> > pagefault_disable() and/or preempt_disable()).
> >
> > Signed-off-by: Deepak R Varma <[email protected]>
> > ---
> > Note: The Patch is build tested only. I will be happy to run recommended testing
> > with some guidance if required.
> >
> > Changes in v2:
> > - Update patch description to correct the replacement function name from
> > kmap_local_folio to kmap_local _page
> >
> >
> > fs/gfs2/aops.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
> > index 3b41542d6697..7bd92054d353 100644
> > --- a/fs/gfs2/aops.c
> > +++ b/fs/gfs2/aops.c
> > @@ -432,10 +432,10 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
> > if (error)
> > return error;
> >
> > - kaddr = kmap_atomic(page);
> > + kaddr = kmap_local_page(page);
> > memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
> > memset(kaddr + dsize, 0, PAGE_SIZE - dsize);
> > - kunmap_atomic(kaddr);
> > + kunmap_local(kaddr);
> > flush_dcache_page(page);
> > brelse(dibh);
> > SetPageUptodate(page);
> > @@ -498,12 +498,12 @@ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
> > continue;
> > return PTR_ERR(page);
> > }
> > - p = kmap_atomic(page);
> > + p = kmap_local_page(page);
> > amt = size - copied;
> > if (offset + size > PAGE_SIZE)
> > amt = PAGE_SIZE - offset;
> > memcpy(buf + copied, p + offset, amt);
> > - kunmap_atomic(p);
> > + kunmap_local(p);
> > put_page(page);
> > copied += amt;
> > index++;
> > --
> > 2.34.1
> >
> >
> >
>