2023-06-17 12:15:48

by David Howells

[permalink] [raw]
Subject: [PATCH net-next v2 17/17] net: Kill MSG_SENDPAGE_NOTLAST

Now that ->sendpage() has been removed, MSG_SENDPAGE_NOTLAST can be cleaned
up. Things were converted to use MSG_MORE instead, but the protocol
sendpage stubs still convert MSG_SENDPAGE_NOTLAST to MSG_MORE, which is now
unnecessary.

Signed-off-by: David Howells <[email protected]>
cc: "David S. Miller" <[email protected]>
cc: Eric Dumazet <[email protected]>
cc: Jakub Kicinski <[email protected]>
cc: Paolo Abeni <[email protected]>
cc: Jens Axboe <[email protected]>
cc: Matthew Wilcox <[email protected]>
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
---
include/linux/socket.h | 4 +---
net/ipv4/tcp_bpf.c | 4 +++-
net/tls/tls_device.c | 3 +--
net/tls/tls_main.c | 2 +-
net/tls/tls_sw.c | 2 +-
tools/perf/trace/beauty/include/linux/socket.h | 1 -
tools/perf/trace/beauty/msg_flags.c | 3 ---
7 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/include/linux/socket.h b/include/linux/socket.h
index 58204700018a..39b74d83c7c4 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -319,7 +319,6 @@ struct ucred {
#define MSG_MORE 0x8000 /* Sender will send more */
#define MSG_WAITFORONE 0x10000 /* recvmmsg(): block until 1+ packets avail */
#define MSG_SENDPAGE_NOPOLICY 0x10000 /* sendpage() internal : do no apply policy */
-#define MSG_SENDPAGE_NOTLAST 0x20000 /* sendpage() internal : not the last page */
#define MSG_BATCH 0x40000 /* sendmmsg(): more messages coming */
#define MSG_EOF MSG_FIN
#define MSG_NO_SHARED_FRAGS 0x80000 /* sendpage() internal : page frags are not shared */
@@ -341,8 +340,7 @@ struct ucred {

/* Flags to be cleared on entry by sendmsg and sendmmsg syscalls */
#define MSG_INTERNAL_SENDMSG_FLAGS \
- (MSG_SPLICE_PAGES | MSG_SENDPAGE_NOPOLICY | MSG_SENDPAGE_NOTLAST | \
- MSG_SENDPAGE_DECRYPTED)
+ (MSG_SPLICE_PAGES | MSG_SENDPAGE_NOPOLICY | MSG_SENDPAGE_DECRYPTED)

/* Setsockoptions(2) level. Thanks to BSD these must match IPPROTO_xxx */
#define SOL_IP 0
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 870c1cde4010..8f535e436ea3 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -90,7 +90,9 @@ static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
{
bool apply = apply_bytes;
struct scatterlist *sge;
- struct msghdr msghdr = { .msg_flags = flags | MSG_SPLICE_PAGES, };
+ struct msghdr msghdr = {
+ .msg_flags = flags | MSG_SPLICE_PAGES | MSG_MORE,
+ };
struct page *page;
int size, ret = 0;
u32 off;
diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index 840ee06f1708..2021fe557e50 100644
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -441,8 +441,7 @@ static int tls_push_data(struct sock *sk,
long timeo;

if (flags &
- ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_SENDPAGE_NOTLAST |
- MSG_SPLICE_PAGES))
+ ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_SPLICE_PAGES))
return -EOPNOTSUPP;

if (unlikely(sk->sk_err))
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index d5ed4d47b16e..b6896126bb92 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -127,7 +127,7 @@ int tls_push_sg(struct sock *sk,
{
struct bio_vec bvec;
struct msghdr msg = {
- .msg_flags = MSG_SENDPAGE_NOTLAST | MSG_SPLICE_PAGES | flags,
+ .msg_flags = MSG_SPLICE_PAGES | flags,
};
int ret = 0;
struct page *p;
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 9b3aa89a4292..53f944e6d8ef 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1194,7 +1194,7 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)

if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL |
MSG_CMSG_COMPAT | MSG_SPLICE_PAGES |
- MSG_SENDPAGE_NOTLAST | MSG_SENDPAGE_NOPOLICY))
+ MSG_SENDPAGE_NOPOLICY))
return -EOPNOTSUPP;

ret = mutex_lock_interruptible(&tls_ctx->tx_lock);
diff --git a/tools/perf/trace/beauty/include/linux/socket.h b/tools/perf/trace/beauty/include/linux/socket.h
index 13c3a237b9c9..3bef212a24d7 100644
--- a/tools/perf/trace/beauty/include/linux/socket.h
+++ b/tools/perf/trace/beauty/include/linux/socket.h
@@ -318,7 +318,6 @@ struct ucred {
#define MSG_MORE 0x8000 /* Sender will send more */
#define MSG_WAITFORONE 0x10000 /* recvmmsg(): block until 1+ packets avail */
#define MSG_SENDPAGE_NOPOLICY 0x10000 /* sendpage() internal : do no apply policy */
-#define MSG_SENDPAGE_NOTLAST 0x20000 /* sendpage() internal : not the last page */
#define MSG_BATCH 0x40000 /* sendmmsg(): more messages coming */
#define MSG_EOF MSG_FIN
#define MSG_NO_SHARED_FRAGS 0x80000 /* sendpage() internal : page frags are not shared */
diff --git a/tools/perf/trace/beauty/msg_flags.c b/tools/perf/trace/beauty/msg_flags.c
index ea68db08b8e7..b5b580e5a77e 100644
--- a/tools/perf/trace/beauty/msg_flags.c
+++ b/tools/perf/trace/beauty/msg_flags.c
@@ -8,9 +8,6 @@
#ifndef MSG_WAITFORONE
#define MSG_WAITFORONE 0x10000
#endif
-#ifndef MSG_SENDPAGE_NOTLAST
-#define MSG_SENDPAGE_NOTLAST 0x20000
-#endif
#ifndef MSG_FASTOPEN
#define MSG_FASTOPEN 0x20000000
#endif



2023-06-18 17:01:57

by Willem de Bruijn

[permalink] [raw]
Subject: RE: [PATCH net-next v2 17/17] net: Kill MSG_SENDPAGE_NOTLAST

David Howells wrote:
> Now that ->sendpage() has been removed, MSG_SENDPAGE_NOTLAST can be cleaned
> up. Things were converted to use MSG_MORE instead, but the protocol
> sendpage stubs still convert MSG_SENDPAGE_NOTLAST to MSG_MORE, which is now
> unnecessary.
>
> Signed-off-by: David Howells <[email protected]>
> cc: "David S. Miller" <[email protected]>
> cc: Eric Dumazet <[email protected]>
> cc: Jakub Kicinski <[email protected]>
> cc: Paolo Abeni <[email protected]>
> cc: Jens Axboe <[email protected]>
> cc: Matthew Wilcox <[email protected]>
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> ---
> include/linux/socket.h | 4 +---
> net/ipv4/tcp_bpf.c | 4 +++-
> net/tls/tls_device.c | 3 +--
> net/tls/tls_main.c | 2 +-
> net/tls/tls_sw.c | 2 +-
> tools/perf/trace/beauty/include/linux/socket.h | 1 -
> tools/perf/trace/beauty/msg_flags.c | 3 ---
> 7 files changed, 7 insertions(+), 12 deletions(-)
>

> @@ -90,7 +90,9 @@ static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
> {
> bool apply = apply_bytes;
> struct scatterlist *sge;
> - struct msghdr msghdr = { .msg_flags = flags | MSG_SPLICE_PAGES, };
> + struct msghdr msghdr = {
> + .msg_flags = flags | MSG_SPLICE_PAGES | MSG_MORE,
> + };
> struct page *page;
> int size, ret = 0;
> u32 off;

Is it intentional to add MSG_MORE here in this patch?

I do see that patch 3 removes this branch:

@@ -111,9 +111,6 @@ static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
if (has_tx_ulp)
msghdr.msg_flags |= MSG_SENDPAGE_NOPOLICY;

- if (flags & MSG_SENDPAGE_NOTLAST)
- msghdr.msg_flags |= MSG_MORE;
-

2023-06-19 12:11:05

by David Howells

[permalink] [raw]
Subject: Re: [PATCH net-next v2 17/17] net: Kill MSG_SENDPAGE_NOTLAST

Willem de Bruijn <[email protected]> wrote:

> Is it intentional to add MSG_MORE here in this patch?
>
> I do see that patch 3 removes this branch:

Yeah. I think I may have tcp_bpf a bit wrong with regard to handling
MSG_MORE.

How about the attached version of tcp_bpf_push()?

I wonder if it's save to move the setting of MSG_SENDPAGE_NOPOLICY out of the
loop as I've done here. The caller holds the socket lock.

Also, I'm not sure whether to take account of apply/apply_bytes when setting
MSG_MORE mid-message, or whether to just go on whether we've reached
sge->length yet. (I'm not sure exactly how tcp_bpf works).

David
---

static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
int flags, bool uncharge)
{
bool apply = apply_bytes;
struct scatterlist *sge;
struct page *page;
int size, ret = 0;
u32 off;

flags |= MSG_SPLICE_PAGES;
if (tls_sw_has_ctx_tx(sk))
msghdr.msg_flags |= MSG_SENDPAGE_NOPOLICY;

while (1) {
struct msghdr msghdr = {};
struct bio_vec bvec;

sge = sk_msg_elem(msg, msg->sg.start);
size = (apply && apply_bytes < sge->length) ?
apply_bytes : sge->length;
off = sge->offset;
page = sg_page(sge);

tcp_rate_check_app_limited(sk);
retry:
msghdr.msg_flags = flags;

/* Determine if we need to set MSG_MORE. */
if (!(msghdr.msg_flags & MSG_MORE)) {
if (apply && size < apply_bytes)
msghdr.msg_flags |= MSG_MORE;
else if (!apply && size < sge->length &&
msg->sg.start != msg->sg.end)
msghdr.msg_flags |= MSG_MORE;
}

bvec_set_page(&bvec, page, size, off);
iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, size);
ret = tcp_sendmsg_locked(sk, &msghdr, size);
if (ret <= 0)
return ret;

if (apply)
apply_bytes -= ret;
msg->sg.size -= ret;
sge->offset += ret;
sge->length -= ret;
if (uncharge)
sk_mem_uncharge(sk, ret);
if (ret != size) {
size -= ret;
off += ret;
goto retry;
}
if (!sge->length) {
put_page(page);
sk_msg_iter_next(msg, start);
sg_init_table(sge, 1);
if (msg->sg.start == msg->sg.end)
break;
}
if (apply && !apply_bytes)
break;
}

return 0;
}


2023-06-20 13:00:16

by Willem de Bruijn

[permalink] [raw]
Subject: Re: [PATCH net-next v2 17/17] net: Kill MSG_SENDPAGE_NOTLAST

David Howells wrote:
> Willem de Bruijn <[email protected]> wrote:
>
> > Is it intentional to add MSG_MORE here in this patch?
> >
> > I do see that patch 3 removes this branch:
>
> Yeah. I think I may have tcp_bpf a bit wrong with regard to handling
> MSG_MORE.
>
> How about the attached version of tcp_bpf_push()?
>
> I wonder if it's save to move the setting of MSG_SENDPAGE_NOPOLICY out of the
> loop as I've done here. The caller holds the socket lock.
>
> Also, I'm not sure whether to take account of apply/apply_bytes when setting
> MSG_MORE mid-message, or whether to just go on whether we've reached
> sge->length yet. (I'm not sure exactly how tcp_bpf works).

I'm not very familiar with it either.

Instead of inferring whether MSG_MORE is safe to set, as below, sufficient to
rely on the caller to pass it when appropriate?

size = min(apply_bytes, sge->length). I doubt that size < apply_bytes is
ever intended.

And instead of this former branch

if (flags & MSG_SENDPAGE_NOTLAST)
msghdr.msg_flags |= MSG_MORE;

update any caller to pass MSG_MORE instead of MSG_SENDPAGE_NOTLAST, if not yet
done so.

> msghdr.msg_flags = flags;
>
> /* Determine if we need to set MSG_MORE. */
> if (!(msghdr.msg_flags & MSG_MORE)) {
> if (apply && size < apply_bytes)
> msghdr.msg_flags |= MSG_MORE;
> else if (!apply && size < sge->length &&
> msg->sg.start != msg->sg.end)
> msghdr.msg_flags |= MSG_MORE;
> }