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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH net-next v8 00/16] splice, net: Replace sendpage with sendmsg(MSG_SPLICE_PAGES), part 1 Date: Thu, 18 May 2023 12:34:37 +0100 Message-Id: <20230518113453.1350757-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 X-Rspamd-Queue-Id: E5AED20012 X-Stat-Signature: 568brx1dwpwqkwqywpxgfacdn6utgqfa X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1684409702-345741 X-HE-Meta: U2FsdGVkX1+wXhLrwasZg0Ein4kM4plF1panJe8Wnv06ppNH69efPZ72lITm5tmNxiNcnSXr+jX29oFN1NQkDPfew5QhaQyD7PLJwpznxzw3gGo1/wAR7Ilj83S+R2bBegDuBXFqMYtWypWTggT/Lq0fjYqxmQiQ4pTFg1AfWWbszCny9i2K/dkgu6Wb6/qCLYnhAMhvXIgA2BIZLjnueEelCy4UFs95CT8puOusWJL4ArtFDzbThdK3KFTbN1z8ugyaicWj9ODrx+m0wcT23P1eGu4OH/hrbE6ddAraA0w6ZH9PsdBuMN1JGyeCi6sIZzGU7oKY98MoAhHc1isT+DV2+glI9Gh6N44y/pDgymJPU61NBdsPGYEPGBJibCP3csi8bMvSLHc+pwumr5kdqezURF+UTsnsvrYAvc6V8tOZPDhvpCjAix+G5kvMRVS0tBWlusUjLhj3WnmnRPi3TRrTwO3RuxuRh0h5eKLI3R16iODa42oMoCaokveAJOEPtmrQh2h07uchUjgMLkkeqscEIufwdfARrO47wjObLEXa6p3OXFBOZqQMEFNFSU5eXOI5Gc8l3xZf70gLTEjLMtMmTlq+30dt0EoPu+T21le3ZK9wmQM0jn4OuuJy66ADRroxAd479jpe1ikfCukINEjkeYWvpnFKtBOrPouL18cZuFtWWJLz4nQQ6xQGSsdhFelKYoyRWHlRnk/VI1a8A6YVPOlXPvQ0uLrxY8MEbH9P7Z5SdR51QpZXbRH1+QhCwBk3MyM2MAo4VPveMai3UAI0nPnGcrDMKAeGqpn1T2wC/g5Y24yZ/TTm//WLDsAsAygxoMpmzT0J1w6PJaflfC2Gb1t0+IdipHQg+1rIXqn5KXC4IoosWsGjkyux6jz4UQIrJ7WtmrizhKOwUQjGftiOpdxYXC+Wtk35pGJkcq8U6bWZse8R7tpr3Ew13bHN4hB2/R6UmHjIb10pRma TOtnK8lS zuoKFB+50J6PHHnL2y28q6UiQtj9gQydvL3DlJGDK1uqUlX83QdJbx/wzf+GWRYn6ged0yt3Aou86RCNOCTrQsYtOR5aKySEY/yA7cKpADNtVw6WyRR9J1sJ3ugBo5Ft2tgpHiu+wJtkqUsyaRFoysLdJdvPn5FT0bPWvOP8dj+wqHg00HQWkI+3HeOupjxK3JVY79TokACPxzfb1+xEx8O3Vm2U3PLNsD5gQbKp5FZBoGYCxfCRTudiBjsUOHAYkpl3UtRiWrjAkgpz6r8HdGxdR0d+akdyi1dUKcm70r1vjEXf0nABBWhSIq3Km95+I670lX2djOF0r/6bJnqfeLTIpbWIOQHEGtTG1 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: Here's the first tranche of patches towards providing a MSG_SPLICE_PAGES internal sendmsg flag that is intended to replace the ->sendpage() op with calls to sendmsg(). MSG_SPLICE_PAGES is a hint that tells the protocol that it should splice the pages supplied if it can and copy them if not. This will allow splice to pass multiple pages in a single call and allow certain parts of higher protocols (e.g. sunrpc, iwarp) to pass an entire message in one go rather than having to send them piecemeal. This should also make it easier to handle the splicing of multipage folios. A helper, skb_splice_from_iter() is provided to do the work of splicing or copying data from an iterator. If a page is determined to be unspliceable (such as being in the slab), then the helper will give an error. Note that this facility is not made available to userspace and does not provide any sort of callback. This set consists of the following parts: (1) Define the MSG_SPLICE_PAGES flag and prevent sys_sendmsg() from being able to set it. (2) Add an extra argument to skb_append_pagefrags() so that something other than MAX_SKB_FRAGS can be used (sysctl_max_skb_frags for example). (3) Add the skb_splice_from_iter() helper to handle splicing pages into skbuffs for MSG_SPLICE_PAGES that can be shared by TCP, IP/UDP and AF_UNIX. (4) Implement MSG_SPLICE_PAGES support in TCP. (5) Make do_tcp_sendpages() just wrap sendmsg() and then fold it in to its various callers. (6) Implement MSG_SPLICE_PAGES support in IP and make udp_sendpage() just a wrapper around sendmsg(). (7) Implement MSG_SPLICE_PAGES support in IP6/UDP6. (8) Implement MSG_SPLICE_PAGES support in AF_UNIX. (9) Make AF_UNIX copy unspliceable pages. I've pushed the patches here also: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=sendpage-1 The follow-on patches are on branch iov-sendpage on the same tree. David Changes ======= ver #8) - Order local variables in reverse xmas tree order. - Remove duplicate coalescence check. - Warn if sendpage_ok() fails. ver #7) - Rebase after merge window. - In ____sys_sendmsg(), clear internal flags before setting msg_flags. - Clear internal flags in uring io_send{,_zc}(). - Export skb_splice_from_iter(). - Missed changing a "zc = 1" in tcp_sendmsg_locked(). - Remove now-unused csum_page() from UDP. - Add a patch to make AF_UNIX sendpage() just a wrapper around sendmsg(). - Return an error if !sendpage_ok() rather than copying for now. - Drop the page frag allocator patches for the moment. ver #6) - Removed a couple of leftover page pointer declarations. - In TCP, set zc to 0/MSG_ZEROCOPY/MSG_SPLICE_PAGES rather than 0/1/2. - Add a max-frags argument to skb_append_pagefrags(). - Extract the AF_UNIX helper out into a common helper and use it for IP/UDP and TCP too. - udp_sendpage() shouldn't lock the socket around udp_sendmsg(). - udp_sendpage() should only set MSG_MORE if MSG_SENDPAGE_NOTLAST is set. - In siw, don't clear MSG_SPLICE_PAGES on the last page. ver #5) - Dropped the samples patch as it causes lots of failures in the patchwork 32-bit builds due to apparent libc userspace header issues. - Made the pagefrag alloc patches alter the Google gve driver too. - Rearranged the patches to put the support in IP before altering UDP. ver #4) - Added some sample socket-I/O programs into samples/net/. - Fix a missing page-get in AF_KCM. - Init the sgtable and mark the end in AF_ALG when calling netfs_extract_iter_to_sg(). - Add a destructor func for page frag caches prior to generalising it and making it per-cpu. ver #3) - Dropped the iterator-of-iterators patch. - Only expunge MSG_SPLICE_PAGES in sys_send[m]msg, not sys_recv[m]msg. - Split MSG_SPLICE_PAGES code in __ip_append_data() out into helper functions. - Implement MSG_SPLICE_PAGES support in __ip6_append_data() using the above helper functions. - Rename 'xlength' to 'initial_length'. - Minimise the changes to sunrpc for the moment. - Don't give -EOPNOTSUPP if NETIF_F_SG not available, just copy instead. - Implemented MSG_SPLICE_PAGES support in the TLS, Chelsio-TLS and AF_KCM code. ver #2) - Overhauled the page_frag_alloc() allocator: large folios and per-cpu. - Got rid of my own zerocopy allocator. - Use iov_iter_extract_pages() rather poking in iter->bvec. - Made page splicing fall back to page copying on a page-by-page basis. - Made splice_to_socket() pass 16 pipe buffers at a time. - Made AF_ALG/hash use finup/digest where possible in sendmsg. - Added an iterator-of-iterators, ITER_ITERLIST. - Made sunrpc use the iterator-of-iterators. - Converted more drivers. Link: https://lore.kernel.org/r/20230316152618.711970-1-dhowells@redhat.com/ # v1 Link: https://lore.kernel.org/r/20230329141354.516864-1-dhowells@redhat.com/ # v2 Link: https://lore.kernel.org/r/20230331160914.1608208-1-dhowells@redhat.com/ # v3 Link: https://lore.kernel.org/r/20230405165339.3468808-1-dhowells@redhat.com/ # v4 Link: https://lore.kernel.org/r/20230406094245.3633290-1-dhowells@redhat.com/ # v5 Link: https://lore.kernel.org/r/20230411160902.4134381-1-dhowells@redhat.com/ # v6 Link: https://lore.kernel.org/r/20230515093345.396978-1-dhowells@redhat.com/ # v7 David Howells (16): net: Declare MSG_SPLICE_PAGES internal sendmsg() flag net: Pass max frags into skb_append_pagefrags() net: Add a function to splice pages into an skbuff for MSG_SPLICE_PAGES tcp: Support MSG_SPLICE_PAGES tcp: Convert do_tcp_sendpages() to use MSG_SPLICE_PAGES tcp_bpf: Inline do_tcp_sendpages as it's now a wrapper around tcp_sendmsg espintcp: Inline do_tcp_sendpages() tls: Inline do_tcp_sendpages() siw: Inline do_tcp_sendpages() tcp: Fold do_tcp_sendpages() into tcp_sendpage_locked() ip, udp: Support MSG_SPLICE_PAGES ip6, udp6: Support MSG_SPLICE_PAGES udp: Convert udp_sendpage() to use MSG_SPLICE_PAGES ip: Remove ip_append_page() af_unix: Support MSG_SPLICE_PAGES unix: Convert udp_sendpage() to use MSG_SPLICE_PAGES drivers/infiniband/sw/siw/siw_qp_tx.c | 17 +- include/linux/skbuff.h | 5 +- include/linux/socket.h | 3 + include/net/ip.h | 2 - include/net/tcp.h | 2 - include/net/tls.h | 2 +- io_uring/net.c | 2 + net/core/skbuff.c | 92 ++++++++++- net/ipv4/ip_output.c | 164 +++----------------- net/ipv4/tcp.c | 214 ++++++-------------------- net/ipv4/tcp_bpf.c | 20 ++- net/ipv4/udp.c | 51 +----- net/ipv6/ip6_output.c | 17 ++ net/socket.c | 2 + net/tls/tls_main.c | 24 +-- net/unix/af_unix.c | 183 +++++----------------- net/xfrm/espintcp.c | 10 +- 17 files changed, 278 insertions(+), 532 deletions(-)