Fix the mishandling of MSG_DONTWAIT and also reinstates the per-page checking of the source pages (which might have come from a DIO write by userspace) by partially reverting the changes to support MSG_SPLICE_PAGES and doing things a little differently. In messenger_v1: (1) The ceph_tcp_sendpage() is resurrected and the callers reverted to use that. (2) The callers now pass MSG_MORE unconditionally. Previously, they were passing in MSG_MORE|MSG_SENDPAGE_NOTLAST and then degrading that to just MSG_MORE on the last call to ->sendpage(). (3) Make ceph_tcp_sendpage() a wrapper around sendmsg() rather than sendpage(), setting MSG_SPLICE_PAGES if sendpage_ok() returns true on the page. In messenger_v2: (4) Bring back do_try_sendpage() and make the callers use that. (5) Make do_try_sendpage() use sendmsg() for both cases and set MSG_SPLICE_PAGES if sendpage_ok() is set. Fixes: 40a8c17aa770 ("ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage") Fixes: fa094ccae1e7 ("ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage()") Reported-by: Ilya Dryomov <idryomov@gmail.com> Link: https://lore.kernel.org/r/CAOi1vP9vjLfk3W+AJFeexC93jqPaPUn2dD_4NrzxwoZTbYfOnw@mail.gmail.com/ Link: https://lore.kernel.org/r/CAOi1vP_Bn918j24S94MuGyn+Gxk212btw7yWeDrRcW1U8pc_BA@mail.gmail.com/ Signed-off-by: David Howells <dhowells@redhat.com> cc: Xiubo Li <xiubli@redhat.com> cc: Jeff Layton <jlayton@kernel.org> cc: Jens Axboe <axboe@kernel.dk> cc: Matthew Wilcox <willy@infradead.org> Link: https://lore.kernel.org/r/3101881.1687801973@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/3111635.1687813501@warthog.procyon.org.uk/ # v2 Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Link: https://lore.kernel.org/r/3199652.1687873788@warthog.procyon.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>