netdev - Re: [PATCH v2 3/4] drbd: use sendpages_ok() instead of sendpage

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Message-ID: <c117893f-865a-4fdf-a480-705c31a72ee3@linbit.com>
Date: Tue, 4 Jun 2024 16:43:36 +0200
From: Christoph Böhmwalder <christoph.boehmwalder@...bit.com>
To: Ofir Gal <ofir.gal@...umez.com>, davem@...emloft.net,
 linux-block@...r.kernel.org, linux-nvme@...ts.infradead.org,
 netdev@...r.kernel.org, ceph-devel@...r.kernel.org
Cc: dhowells@...hat.com, edumazet@...gle.com, pabeni@...hat.com,
 philipp.reisner@...bit.com, lars.ellenberg@...bit.com
Subject: Re: [PATCH v2 3/4] drbd: use sendpages_ok() instead of sendpage_ok()

Am 30.05.24 um 16:24 schrieb Ofir Gal:
> Currently _drbd_send_page() use sendpage_ok() in order to enable
> MSG_SPLICE_PAGES, it check the first page of the iterator, the iterator
> may represent contiguous pages.
> 
> MSG_SPLICE_PAGES enables skb_splice_from_iter() which checks all the
> pages it sends with sendpage_ok().
> 
> When _drbd_send_page() sends an iterator that the first page is
> sendable, but one of the other pages isn't skb_splice_from_iter() warns
> and aborts the data transfer.
> 
> Using the new helper sendpages_ok() in order to enable MSG_SPLICE_PAGES
> solves the issue.
> 
> Signed-off-by: Ofir Gal <ofir.gal@...umez.com>
> ---
>  drivers/block/drbd/drbd_main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
> index 113b441d4d36..a5dbbf6cce23 100644
> --- a/drivers/block/drbd/drbd_main.c
> +++ b/drivers/block/drbd/drbd_main.c
> @@ -1550,7 +1550,7 @@ static int _drbd_send_page(struct drbd_peer_device *peer_device, struct page *pa
>  	 * put_page(); and would cause either a VM_BUG directly, or
>  	 * __page_cache_release a page that would actually still be referenced
>  	 * by someone, leading to some obscure delayed Oops somewhere else. */
> -	if (!drbd_disable_sendpage && sendpage_ok(page))
> +	if (!drbd_disable_sendpage && sendpages_ok(page, len, offset))
>  		msg.msg_flags |= MSG_NOSIGNAL | MSG_SPLICE_PAGES;
>  
>  	drbd_update_congested(peer_device->connection);

Acked-by: Christoph Böhmwalder <christoph.boehmwalder@...bit.com>

-- 
Christoph Böhmwalder
LINBIT | Keeping the Digital World Running
DRBD HA —  Disaster Recovery — Software defined Storage