2020-06-09 23:34:57

by Stephen Rothwell

[permalink] [raw]

Subject: linux-next: manual merge of the net tree with Linus' tree

---

Hi all,

Today's linux-next merge of the net tree got a conflict in:

net/ipv4/tcp.c

between commit:

d8ed45c5dcd4 ("mmap locking API: use coccinelle to convert mmap_sem rwsem call sites")

from Linus' tree and commit:

3763a24c727e ("net-zerocopy: use vm_insert_pages() for tcp rcv zerocopy")

from the net tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging. You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

--
Cheers,
Stephen Rothwell

diff --cc net/ipv4/tcp.c
index 27716e4932bc,ecbba0abd3e5..000000000000
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@@ -1762,7 -1796,9 +1796,9 @@@ static int tcp_zerocopy_receive(struct

sock_rps_record_flow(sk);

+ tp = tcp_sk(sk);
+
- down_read(&current->mm->mmap_sem);
+ mmap_read_lock(current->mm);

vma = find_vma(current->mm, address);
if (!vma || vma->vm_start > address || vma->vm_ops != &tcp_vm_ops) {
@@@ -1817,17 -1863,27 +1863,27 @@@
zc->recv_skip_hint -= remaining;
break;
}
- ret = vm_insert_page(vma, address + length,
- skb_frag_page(frags));
- if (ret)
- break;
+ pages[pg_idx] = skb_frag_page(frags);
+ pg_idx++;
length += PAGE_SIZE;
- seq += PAGE_SIZE;
zc->recv_skip_hint -= PAGE_SIZE;
frags++;
+ if (pg_idx == PAGE_BATCH_SIZE) {
+ ret = tcp_zerocopy_vm_insert_batch(vma, pages, pg_idx,
+ &curr_addr, &length,
+ &seq, zc);
+ if (ret)
+ goto out;
+ pg_idx = 0;
+ }
+ }
+ if (pg_idx) {
+ ret = tcp_zerocopy_vm_insert_batch(vma, pages, pg_idx,
+ &curr_addr, &length, &seq,
+ zc);
}
out:
- up_read(&current->mm->mmap_sem);
+ mmap_read_unlock(current->mm);
if (length) {
WRITE_ONCE(tp->copied_seq, seq);
tcp_rcv_space_adjust(sk);

---

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2020-06-10 00:00:57

by Arjun Roy

[permalink] [raw]

Subject: Re: linux-next: manual merge of the net tree with Linus' tree

---

Ack, and thank you very much for the fix.

-Arjun


On Tue, Jun 9, 2020 at 4:30 PM Stephen Rothwell <[email protected]> wrote:
>
> Hi all,
>
> Today's linux-next merge of the net tree got a conflict in:
>
> net/ipv4/tcp.c
>
> between commit:
>
> d8ed45c5dcd4 ("mmap locking API: use coccinelle to convert mmap_sem rwsem call sites")
>
> from Linus' tree and commit:
>
> 3763a24c727e ("net-zerocopy: use vm_insert_pages() for tcp rcv zerocopy")
>
> from the net tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
> --
> Cheers,
> Stephen Rothwell
>
> diff --cc net/ipv4/tcp.c
> index 27716e4932bc,ecbba0abd3e5..000000000000
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@@ -1762,7 -1796,9 +1796,9 @@@ static int tcp_zerocopy_receive(struct
>
> sock_rps_record_flow(sk);
>
> + tp = tcp_sk(sk);
> +
> - down_read(&current->mm->mmap_sem);
> + mmap_read_lock(current->mm);
>
> vma = find_vma(current->mm, address);
> if (!vma || vma->vm_start > address || vma->vm_ops != &tcp_vm_ops) {
> @@@ -1817,17 -1863,27 +1863,27 @@@
> zc->recv_skip_hint -= remaining;
> break;
> }
> - ret = vm_insert_page(vma, address + length,
> - skb_frag_page(frags));
> - if (ret)
> - break;
> + pages[pg_idx] = skb_frag_page(frags);
> + pg_idx++;
> length += PAGE_SIZE;
> - seq += PAGE_SIZE;
> zc->recv_skip_hint -= PAGE_SIZE;
> frags++;
> + if (pg_idx == PAGE_BATCH_SIZE) {
> + ret = tcp_zerocopy_vm_insert_batch(vma, pages, pg_idx,
> + &curr_addr, &length,
> + &seq, zc);
> + if (ret)
> + goto out;
> + pg_idx = 0;
> + }
> + }
> + if (pg_idx) {
> + ret = tcp_zerocopy_vm_insert_batch(vma, pages, pg_idx,
> + &curr_addr, &length, &seq,
> + zc);
> }
> out:
> - up_read(&current->mm->mmap_sem);
> + mmap_read_unlock(current->mm);
> if (length) {
> WRITE_ONCE(tp->copied_seq, seq);
> tcp_rcv_space_adjust(sk);