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

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Message-Id: <20190521045242.24378-11-dave@stgolabs.net>
Date:   Mon, 20 May 2019 21:52:38 -0700
From:   Davidlohr Bueso <dave@...olabs.net>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     akpm@...ux-foundation.org, willy@...radead.org, mhocko@...nel.org,
        mgorman@...hsingularity.net, jglisse@...hat.com,
        ldufour@...ux.vnet.ibm.com, dave@...olabs.net,
        Davidlohr Bueso <dbueso@...e.de>
Subject: [PATCH 10/14] net: teach the mm about range locking

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 <dbueso@...e.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