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Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20230622191134.54d5cb0b@kernel.org> References: <20230622191134.54d5cb0b@kernel.org> <20230622132835.3c4e38ea@kernel.org> <20230622111234.23aadd87@kernel.org> <20230620145338.1300897-1-dhowells@redhat.com> <20230620145338.1300897-2-dhowells@redhat.com> <1952674.1687462843@warthog.procyon.org.uk> <1958077.1687474471@warthog.procyon.org.uk> To: Jakub Kicinski Cc: dhowells@redhat.com, Eric Dumazet , netdev@vger.kernel.org, Alexander Duyck , "David S. Miller" , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Jens Axboe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Menglong Dong Subject: Re: [PATCH net-next v3 01/18] net: Copy slab data for sendmsg(MSG_SPLICE_PAGES) MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1969747.1687511298.1@warthog.procyon.org.uk> Date: Fri, 23 Jun 2023 10:08:18 +0100 Message-ID: <1969749.1687511298@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 60112C0002 X-Stat-Signature: ube6b6fin5zy946uexu8zewjaeyig3id X-Rspam-User: X-HE-Tag: 1687511308-384455 X-HE-Meta: U2FsdGVkX1//12vA9nKMORYnO73Dxu2YpNOCwRAMSbKwdxdr8E48yy9gVm8UoPpJeGY/Ryzswb7xVktME84iG3WMNSrIu5i3XijcudhkDBUeZcZ9Gh72yQqAg7TQ6d2GokSCDTIqCAjz+ez3KrsQQB2e1wB3Yr78sHLBffPZWD4c59eUPERAdrvqCvZwdUHL23yVZ8i1x9QjSDC8gBIinWLDo8xoEFe02CnRxvVZS3yw4o1w8ZzPVuHqOwsq9jVFXBQKulX8TbFUwVfxi/LaIi6RdATDkwDZgdsBsjW5R8mX44DVHo7TNQdS/MdipENooVORqSKKtYi0N+b0CUMreTjqT9/lVdsPMa3O6aZI5+WdYXoEUZ/6BcVTFErpIMisYOtFSigGY0lNSkPoEzkAObeZuihmi+6NzOH0/HyIWVLomfGZkUXPZSQctypNhr7Lwpy74bo1S5zWCqBkokYhCE6RN1TkAIP9C89NUt+Xg5Izua/KENLO5Tzo31ub47g6/uhKyerOxuc1llpz92RDkFE+PLRUP4CWsfgMZbln7uOP+1vLg3Wd8LwtoZquLcE9zIv4elmDtDu6y2XjZfdPmglO7KaX4+r3ApAsD9XmAJciMDuYp1vkxcNI7wRX5XC/SiahE6zD9RithuQcHgBHnuQ4G6iLNVX9oal68hZ1FOed1gMkhgX6v9Fhg/rf9/AU5g0IISY1X6EDsIriY1w9taFVaQjrVjNkLpSRgI10pB8Fgbp6MjUqRBBJGyVBL1woA94Mme4koRJoIqqddXt2i+YhNEMnbyCOe3CukmCgEB1jYmBnLlrZ12F0NWeYJcKT+3SsYsmDkUfsZFFCzqFVw0TX78LEgDoRWauMplblUD9bPBBbiIEY+JBgo5HvfwFW6TxFamV/2zfjh1Ht3XSRzC4JhnfjiqjmfqdpChwxn8Lp6YPhCTP0L9mTrkX4nUqdERt615p8A6l3tLqN3mw oKfFbvxt wBxS8tPacuDVAi/bpeYgfqk7T5U+Y5hxRxFrdxuO8yknUjaiieK8SFB37PZMonTPf4Y8I8RuKcm9E5koXsnSwCk8Y7N5Z2beYKq4Sfz8iatJKSEFai9gNmjYhwz2YAOQ4PYtqEh6aVzr+TWzVc8zO64X8X6M0+jDTv3OAEREfQpyzKZAC/Z/yyWB48qqJ+sqjFKUawW7YS5uerUPS+BHKfqYFG/ThMHd92FsIAxaNNMFZlNZCnWYmmLhVXNaIVEXKm3u0YGZonmdhPLUe+rbnaXZDfr9e7fu3/4+Zjx34/OFskcBXSyBtLlb2bqpN6Hgjt/KRIxzh2Jj4oWCF3H8ZkF1DNlkdfhRANPOq X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Jakub Kicinski wrote: > If we can't reach instant agreement -- > can you strategically separate out the minimal set of changes required > to just kill MSG_SENDPAGE_NOTLAST. IMHO it's worth getting that into > 6.5. Paolo Abeni wrote: > Given all the above, and the late stage of the current devel cycle, > would you consider slicing down this series to just kill > MSG_SENDPAGE_NOTLAST, as Jakub suggested? I could do that. There is also another alternative. I could just push the sendpage wrappers up the stack into the higher-level callers. Basically this: int udp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, int flags) { struct bio_vec bvec; struct msghdr msg = { .msg_flags = flags | MSG_SPLICE_PAGES }; if (flags & MSG_SENDPAGE_NOTLAST) msg.msg_flags |= MSG_MORE; bvec_set_page(&bvec, page, size, offset); iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size); return udp_sendmsg(sk, &msg, size); } and kill off sendpage and MSG_SENDPAGE_NOTLAST. David