On 7/17/24 23:26, Ilya Dryomov wrote: > On Tue, Jul 16, 2024 at 2:46 PM Ofir Gal <ofir.gal@xxxxxxxxxxx> wrote: >> >> Xiubo/Ilya please take a look >> >> On 6/11/24 09:36, Ofir Gal wrote: >>> Currently ceph_tcp_sendpage() and do_try_sendpage() 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 ceph_tcp_sendpage() or do_try_sendpage() send 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@xxxxxxxxxxx> >>> --- >>> net/ceph/messenger_v1.c | 2 +- >>> net/ceph/messenger_v2.c | 2 +- >>> 2 files changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/net/ceph/messenger_v1.c b/net/ceph/messenger_v1.c >>> index 0cb61c76b9b8..a6788f284cd7 100644 >>> --- a/net/ceph/messenger_v1.c >>> +++ b/net/ceph/messenger_v1.c >>> @@ -94,7 +94,7 @@ static int ceph_tcp_sendpage(struct socket *sock, struct page *page, >>> * coalescing neighboring slab objects into a single frag which >>> * triggers one of hardened usercopy checks. >>> */ >>> - if (sendpage_ok(page)) >>> + if (sendpages_ok(page, size, offset)) >>> msg.msg_flags |= MSG_SPLICE_PAGES; >>> >>> bvec_set_page(&bvec, page, size, offset); >>> diff --git a/net/ceph/messenger_v2.c b/net/ceph/messenger_v2.c >>> index bd608ffa0627..27f8f6c8eb60 100644 >>> --- a/net/ceph/messenger_v2.c >>> +++ b/net/ceph/messenger_v2.c >>> @@ -165,7 +165,7 @@ static int do_try_sendpage(struct socket *sock, struct iov_iter *it) >>> * coalescing neighboring slab objects into a single frag >>> * which triggers one of hardened usercopy checks. >>> */ >>> - if (sendpage_ok(bv.bv_page)) >>> + if (sendpages_ok(bv.bv_page, bv.bv_len, bv.bv_offset)) >>> msg.msg_flags |= MSG_SPLICE_PAGES; >>> else >>> msg.msg_flags &= ~MSG_SPLICE_PAGES; >> > > Hi Ofir, > > Ceph should be fine as is -- there is an internal "cursor" abstraction > that that is limited to PAGE_SIZE chunks, using bvec_iter_bvec() instead > of mp_bvec_iter_bvec(), etc. This means that both do_try_sendpage() and > ceph_tcp_sendpage() should be called only with > > page_off + len <= PAGE_SIZE > > being true even if the page is contiguous (and that we lose out on the > potential performance benefit, of course...). > > That said, if the plan is to remove sendpage_ok() so that it doesn't > accidentally grow new users who are unaware of this pitfall, consider > this > > Acked-by: Ilya Dryomov <idryomov@xxxxxxxxx> > > Thanks, > > Ilya I dont think the plan is to remove sendpage_ok() (unless someone says otherwise). Im sending v5 without the libceph patch. Thanks
