From e6762c8bcf982821935a2b1cb33cf8335d0eefae Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Fri, 8 Feb 2019 14:13:50 +0100 Subject: xsk: add missing smp_rmb() in xsk_mmap All the setup code in AF_XDP is protected by a mutex with the exception of the mmap code that cannot use it. To make sure that a process banging on the mmap call at the same time as another process is setting up the socket, smp_wmb() calls were added in the umem registration code and the queue creation code, so that the published structures that xsk_mmap needs would be consistent. However, the corresponding smp_rmb() calls were not added to the xsk_mmap code. This patch adds these calls. Fixes: 37b076933a8e3 ("xsk: add missing write- and data-dependency barrier") Fixes: c0c77d8fb787c ("xsk: add user memory registration support sockopt") Signed-off-by: Magnus Karlsson Signed-off-by: Alexei Starovoitov --- net/xdp/xsk.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'net/xdp') diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index a03268454a27..45f3b528dc09 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -669,6 +669,8 @@ static int xsk_mmap(struct file *file, struct socket *sock, if (!umem) return -EINVAL; + /* Matches the smp_wmb() in XDP_UMEM_REG */ + smp_rmb(); if (offset == XDP_UMEM_PGOFF_FILL_RING) q = READ_ONCE(umem->fq); else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING) @@ -678,6 +680,8 @@ static int xsk_mmap(struct file *file, struct socket *sock, if (!q) return -EINVAL; + /* Matches the smp_wmb() in xsk_init_queue */ + smp_rmb(); qpg = virt_to_head_page(q->ring); if (size > (PAGE_SIZE << compound_order(qpg))) return -EINVAL; -- cgit v1.2.3-59-g8ed1b From e451eb51068496054d071af10b3530af4002a4f4 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Mon, 11 Feb 2019 08:15:29 -0800 Subject: xsk: share the mmap_sem for page pinning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Holding mmap_sem exclusively for a gup() is an overkill. Lets share the lock and replace the gup call for gup_longterm(), as it is better suited for the lifetime of the pinning. Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt") Signed-off-by: Davidlohr Bueso Cc: David S. Miller Cc: Bjorn Topel Cc: Magnus Karlsson CC: netdev@vger.kernel.org Acked-by: Björn Töpel Signed-off-by: Daniel Borkmann --- net/xdp/xdp_umem.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'net/xdp') diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index d4de871e7d4d..597866e7c441 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -259,10 +259,10 @@ static int xdp_umem_pin_pages(struct xdp_umem *umem) if (!umem->pgs) return -ENOMEM; - down_write(¤t->mm->mmap_sem); - npgs = get_user_pages(umem->address, umem->npgs, - gup_flags, &umem->pgs[0], NULL); - up_write(¤t->mm->mmap_sem); + down_read(¤t->mm->mmap_sem); + npgs = get_user_pages_longterm(umem->address, umem->npgs, + gup_flags, &umem->pgs[0], NULL); + up_read(¤t->mm->mmap_sem); if (npgs != umem->npgs) { if (npgs >= 0) { -- cgit v1.2.3-59-g8ed1b From 1e405c1a3f667bf152905127b94e9c8f454a343e Mon Sep 17 00:00:00 2001 From: Björn Töpel Date: Tue, 12 Feb 2019 08:51:14 +0100 Subject: xsk: do not remove umem from netdevice on fall-back to copy-mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit c9b47cc1fabc ("xsk: fix bug when trying to use both copy and zero-copy on one queue id") stores the umem into the netdev._rx struct. However, the patch incorrectly removed the umem from the netdev._rx struct when user-space passed "best-effort" mode (i.e. select the fastest possible option available), and zero-copy mode was not available. This commit fixes that. Fixes: c9b47cc1fabc ("xsk: fix bug when trying to use both copy and zero-copy on one queue id") Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann --- net/xdp/xdp_umem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/xdp') diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index 597866e7c441..37e1fe180769 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -125,9 +125,10 @@ int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev, return 0; err_unreg_umem: - xdp_clear_umem_at_qid(dev, queue_id); if (!force_zc) err = 0; /* fallback to copy mode */ + if (err) + xdp_clear_umem_at_qid(dev, queue_id); out_rtnl_unlock: rtnl_unlock(); return err; -- cgit v1.2.3-59-g8ed1b