RE: [PATCH net-next v5 11/19] siw: Inline do_tcp_sendpages()

[Bernard Metzler <BMT@zurich.ibm.com>]

> -----Original Message-----
> From: David Howells <dhowells@redhat.com>
> Sent: Thursday, 6 April 2023 11:43
> To: netdev@vger.kernel.org
> Cc: David Howells <dhowells@redhat.com>; David S. Miller
> <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub Kicinski
> <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Willem de Bruijn
> <willemdebruijn.kernel@gmail.com>; Matthew Wilcox <willy@infradead.org>; Al
> Viro <viro@zeniv.linux.org.uk>; Christoph Hellwig <hch@infradead.org>; Jens
> Axboe <axboe@kernel.dk>; Jeff Layton <jlayton@kernel.org>; Christian
> Brauner <brauner@kernel.org>; Chuck Lever III <chuck.lever@oracle.com>;
> Linus Torvalds <torvalds@linux-foundation.org>; linux-
> fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; linux-mm@kvack.org;
> Bernard Metzler <BMT@zurich.ibm.com>; Jason Gunthorpe <jgg@ziepe.ca>; Leon
> Romanovsky <leon@kernel.org>; Tom Talpey <tom@talpey.com>; linux-
> rdma@vger.kernel.org
> Subject: [EXTERNAL] [PATCH net-next v5 11/19] siw: Inline
> do_tcp_sendpages()
> 
> do_tcp_sendpages() is now just a small wrapper around tcp_sendmsg_locked(),
> so inline it, allowing do_tcp_sendpages() to be removed.  This is part of
> replacing ->sendpage() with a call to sendmsg() with MSG_SPLICE_PAGES set.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Bernard Metzler <bmt@zurich.ibm.com>
> cc: Jason Gunthorpe <jgg@ziepe.ca>
> cc: Leon Romanovsky <leon@kernel.org>
> cc: Tom Talpey <tom@talpey.com>
> cc: "David S. Miller" <davem@davemloft.net>
> cc: Eric Dumazet <edumazet@google.com>
> cc: Jakub Kicinski <kuba@kernel.org>
> cc: Paolo Abeni <pabeni@redhat.com>
> cc: Jens Axboe <axboe@kernel.dk>
> cc: Matthew Wilcox <willy@infradead.org>
> cc: linux-rdma@vger.kernel.org
> cc: netdev@vger.kernel.org
> ---
>  drivers/infiniband/sw/siw/siw_qp_tx.c | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/siw/siw_qp_tx.c
> b/drivers/infiniband/sw/siw/siw_qp_tx.c
> index 05052b49107f..fa5de40d85d5 100644
> --- a/drivers/infiniband/sw/siw/siw_qp_tx.c
> +++ b/drivers/infiniband/sw/siw/siw_qp_tx.c
> @@ -313,7 +313,7 @@ static int siw_tx_ctrl(struct siw_iwarp_tx *c_tx,
> struct socket *s,
>  }
> 
>  /*
> - * 0copy TCP transmit interface: Use do_tcp_sendpages.
> + * 0copy TCP transmit interface: Use MSG_SPLICE_PAGES.
>   *
>   * Using sendpage to push page by page appears to be less efficient
>   * than using sendmsg, even if data are copied.
> @@ -324,20 +324,27 @@ static int siw_tx_ctrl(struct siw_iwarp_tx *c_tx,
> struct socket *s,
>  static int siw_tcp_sendpages(struct socket *s, struct page **page, int
> offset,
>  			     size_t size)
>  {
> +	struct bio_vec bvec;
> +	struct msghdr msg = {
> +		.msg_flags = (MSG_MORE | MSG_DONTWAIT | MSG_SENDPAGE_NOTLAST |
> +			      MSG_SPLICE_PAGES),
> +	};
>  	struct sock *sk = s->sk;
> -	int i = 0, rv = 0, sent = 0,
> -	    flags = MSG_MORE | MSG_DONTWAIT | MSG_SENDPAGE_NOTLAST;
> +	int i = 0, rv = 0, sent = 0;
> 
>  	while (size) {
>  		size_t bytes = min_t(size_t, PAGE_SIZE - offset, size);
> 
>  		if (size + offset <= PAGE_SIZE)
> -			flags = MSG_MORE | MSG_DONTWAIT;
> +			msg.msg_flags = MSG_MORE | MSG_DONTWAIT;
> 
>  		tcp_rate_check_app_limited(sk);
> +		bvec_set_page(&bvec, page[i], bytes, offset);
> +		iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size);
> +
>  try_page_again:
>  		lock_sock(sk);
> -		rv = do_tcp_sendpages(sk, page[i], offset, bytes, flags);
> +		rv = tcp_sendmsg_locked(sk, &msg, size);
>  		release_sock(sk);
> 
>  		if (rv > 0) {

lgtm.

Reviewd-by: Bernard Metzler <bmt@zurich.ibm.com>