[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <2235268.iZASKD2KPV@suse>
Date: Sat, 01 Jul 2023 15:54:06 +0200
From: "Fabio M. De Francesco" <fmdefrancesco@...il.com>
To: Bob Peterson <rpeterso@...hat.com>,
Andreas Gruenbacher <agruenba@...hat.com>,
cluster-devel@...hat.com, linux-kernel@...r.kernel.org,
Deepak R Varma <drv@...lo.com>
Cc: Ira Weiny <ira.weiny@...el.com>,
Sumitra Sharma <sumitraartsy@...il.com>,
Deepak R Varma <drv@...lo.com>
Subject: Re: [PATCH v3 6/6] gfs2: Replace kmap_atomic() by kmap_local_page() in
gfs2_write_buf_to_page
On giovedì 29 giugno 2023 23:52:27 CEST Deepak R Varma wrote:
> kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().
Deepak,
Again please refer to documentation and/or Ira's deprecation patch. The
reasons why are in one of my previous messages.
> Therefore, replace kmap_atomic() with kmap_local_page() in
> gfs2_write_buf_to_page().
>
> kmap_atomic() disables page-faults and preemption (the latter only for
> !PREEMPT_RT kernels), However, the code within the mapping/un-mapping in
> gfs2_write_buf_to_page() 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()).
>
> Suggested-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
> Signed-off-by: Deepak R Varma <drv@...lo.com>
> ---
> Changes in v3:
> - Patch included in patch set
>
> Changes in v2:
> - None
>
>
> fs/gfs2/quota.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
> index 386ca770ce2e..e5767133aeea 100644
> --- a/fs/gfs2/quota.c
> +++ b/fs/gfs2/quota.c
> @@ -764,10 +764,10 @@ static int gfs2_write_buf_to_page(struct gfs2_inode
*ip,
> unsigned long index, }
>
> /* Write to the page, now that we have setup the buffer(s) */
> - kaddr = kmap_atomic(page);
> + kaddr = kmap_local_page(page);
>
Well, if this page could come from HIGHMEM, how about memcpy_to_page()?
Otherwise, (if it cannot come from HIGHMEM) we don't need to kmap*() it.
Can you please take a look at the allocation's flags?
Thanks,
Fabio
>
> memcpy(kaddr + off, buf, bytes);
> flush_dcache_page(page);
> - kunmap_atomic(kaddr);
> + kunmap_local(kaddr);
> unlock_page(page);
> put_page(page);
>
> --
> 2.34.1
Powered by blists - more mailing lists