2023-06-27 11:44:33

by Fabio M. De Francesco

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

On domenica 25 giugno 2023 21:23:21 CEST Deepak R Varma wrote:
> kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().
>
> Therefore, replace kmap_atomic() with kmap_local_folio() 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.
>
> 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);

How about using memcpy_from_page()?

Fabio

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






2023-06-27 18:59:09

by Deepak R Varma

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

On Tue, Jun 27, 2023 at 01:11:46PM +0200, Fabio M. De Francesco wrote:
> On domenica 25 giugno 2023 21:23:21 CEST Deepak R Varma wrote:
> > kmap_atomic() is deprecated in favor of kmap_local_{folio,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);
>
> How about using memcpy_from_page()?

We can do that. I will include that in v3.

Deepak.

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