[PATCH net] net: tls: set MSG_SPLICE_PAGES consistently

[PATCH net] net: tls: set MSG_SPLICE_PAGES consistently

[Jakub Kicinski]

We used to change the flags for the last segment, because
non-last segments had the MSG_SENDPAGE_NOTLAST flag set.
That flag is no longer a thing so remove the setting.

Since flags most likely don't have MSG_SPLICE_PAGES set
this avoids passing parts of the sg as splice and parts
as non-splice. Before commit under Fixes we'd have called
tcp_sendpage() which would add the MSG_SPLICE_PAGES.

Why this leads to trouble remains unclear but Tariq
reports hitting the WARN_ON(!sendpage_ok()) due to
page refcount of 0.

Fixes: e117dcfd646e ("tls: Inline do_tcp_sendpages()")
Reported-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/all/4c49176f-147a-4283-f1b1-32aac7b4b996@gmail.com/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: borisp@nvidia.com
CC: john.fastabend@gmail.com
CC: dhowells@redhat.com
---
 net/tls/tls_main.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 7dbb8cd8f809..f550c84f3408 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -139,9 +139,6 @@ int tls_push_sg(struct sock *sk,
 
 	ctx->splicing_pages = true;
 	while (1) {
-		if (sg_is_last(sg))
-			msg.msg_flags = flags;
-
 		/* is sending application-limited? */
 		tcp_rate_check_app_limited(sk);
 		p = sg_page(sg);
-- 
2.41.0

Re: [PATCH net] net: tls: set MSG_SPLICE_PAGES consistently

[Tariq Toukan]

On 08/08/2023 21:09, Jakub Kicinski wrote:
> We used to change the flags for the last segment, because
> non-last segments had the MSG_SENDPAGE_NOTLAST flag set.
> That flag is no longer a thing so remove the setting.
> 
> Since flags most likely don't have MSG_SPLICE_PAGES set
> this avoids passing parts of the sg as splice and parts
> as non-splice. Before commit under Fixes we'd have called
> tcp_sendpage() which would add the MSG_SPLICE_PAGES.
> 
> Why this leads to trouble remains unclear but Tariq
> reports hitting the WARN_ON(!sendpage_ok()) due to
> page refcount of 0.
> 
> Fixes: e117dcfd646e ("tls: Inline do_tcp_sendpages()")
> Reported-by: Tariq Toukan <tariqt@nvidia.com>
> Link: https://lore.kernel.org/all/4c49176f-147a-4283-f1b1-32aac7b4b996@gmail.com/
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> CC: borisp@nvidia.com
> CC: john.fastabend@gmail.com
> CC: dhowells@redhat.com
> ---
>   net/tls/tls_main.c | 3 ---
>   1 file changed, 3 deletions(-)
> 
> diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
> index 7dbb8cd8f809..f550c84f3408 100644
> --- a/net/tls/tls_main.c
> +++ b/net/tls/tls_main.c
> @@ -139,9 +139,6 @@ int tls_push_sg(struct sock *sk,
>   
>   	ctx->splicing_pages = true;
>   	while (1) {
> -		if (sg_is_last(sg))
> -			msg.msg_flags = flags;
> -
>   		/* is sending application-limited? */
>   		tcp_rate_check_app_limited(sk);
>   		p = sg_page(sg);


Thanks for your patch.
Tested-by: Tariq Toukan <tariqt@nvidia.com>

Re: [PATCH net] net: tls: set MSG_SPLICE_PAGES consistently

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue,  8 Aug 2023 11:09:17 -0700 you wrote:
> We used to change the flags for the last segment, because
> non-last segments had the MSG_SENDPAGE_NOTLAST flag set.
> That flag is no longer a thing so remove the setting.
> 
> Since flags most likely don't have MSG_SPLICE_PAGES set
> this avoids passing parts of the sg as splice and parts
> as non-splice. Before commit under Fixes we'd have called
> tcp_sendpage() which would add the MSG_SPLICE_PAGES.
> 
> [...]

Here is the summary with links:
  - [net] net: tls: set MSG_SPLICE_PAGES consistently
    https://git.kernel.org/netdev/net/c/6b486676b41c

You are awesome, thank you!
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