On lunedì 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 <d...@mailo.com>
> ---
> 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
