[PATCH 10/14] net: teach the mm about range locking

[Davidlohr Bueso]

Conversion is straightforward, mmap_sem is used within the
the same function context most of the time. No change in
semantics.

Signed-off-by: Davidlohr Bueso <dbu...@suse.de>
---
 net/ipv4/tcp.c     | 5 +++--
 net/xdp/xdp_umem.c | 5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 53d61ca3ac4b..2be929dcafa8 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1731,6 +1731,7 @@ static int tcp_zerocopy_receive(struct sock *sk,
        struct tcp_sock *tp;
        int inq;
        int ret;
+       DEFINE_RANGE_LOCK_FULL(mmrange);
 
        if (address & (PAGE_SIZE - 1) || address != zc->address)
                return -EINVAL;
@@ -1740,7 +1741,7 @@ static int tcp_zerocopy_receive(struct sock *sk,
 
        sock_rps_record_flow(sk);
 
-       down_read(&current->mm->mmap_sem);
+       mm_read_lock(current->mm, &mmrange);
 
        ret = -EINVAL;
        vma = find_vma(current->mm, address);
@@ -1802,7 +1803,7 @@ static int tcp_zerocopy_receive(struct sock *sk,
                frags++;
        }
 out:
-       up_read(&current->mm->mmap_sem);
+       mm_read_unlock(current->mm, &mmrange);
        if (length) {
                tp->copied_seq = seq;
                tcp_rcv_space_adjust(sk);
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 2b18223e7eb8..2bf444fb998d 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -246,16 +246,17 @@ static int xdp_umem_pin_pages(struct xdp_umem *umem)
        unsigned int gup_flags = FOLL_WRITE;
        long npgs;
        int err;
+       DEFINE_RANGE_LOCK_FULL(mmrange);
 
        umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs),
                            GFP_KERNEL | __GFP_NOWARN);
        if (!umem->pgs)
                return -ENOMEM;
 
-       down_read(&current->mm->mmap_sem);
+       mm_read_lock(current->mm, &mmrange);
        npgs = get_user_pages(umem->address, umem->npgs,
                              gup_flags | FOLL_LONGTERM, &umem->pgs[0], NULL);
-       up_read(&current->mm->mmap_sem);
+       mm_read_unlock(current->mm, &mmrange);
 
        if (npgs != umem->npgs) {
                if (npgs >= 0) {
-- 
2.16.4