net/tls: Inform user space about send buffer availability

nxa22042 · davem330 · commit 4504ab0e6eb8 · 2019-03-13T14:16:44.000-07:00
A previous fix ("tls: Fix write space handling") assumed that user space application gets informed about the socket send buffer availability when tls_push_sg() gets called. Inside tls_push_sg(), in case do_tcp_sendpages() returns 0, the function returns without calling ctx->sk_write_space. Further, the new function tls_sw_write_space() did not invoke ctx->sk_write_space. This leads to situation that user space application encounters a lockup always waiting for socket send buffer to become available. Rather than call ctx->sk_write_space from tls_push_sg(), it should be called from tls_write_space. So whenever tcp stack invokes sk->sk_write_space after freeing socket send buffer, we always declare the same to user space by the way of invoking ctx->sk_write_space. Fixes: 7463d3a ("tls: Fix write space handling") Signed-off-by: Vakul Garg <vakul.garg@nxp.com> Reviewed-by: Boris Pismenny <borisp@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
@@ -558,9 +558,6 @@ void tls_device_write_space(struct sock *sk, struct tls_context *ctx)
 					     MSG_DONTWAIT | MSG_NOSIGNAL);
 		sk->sk_allocation = sk_allocation;
 	}
-
-	if (!rc)
-		ctx->sk_write_space(sk);
 }
 
 void handle_device_resync(struct sock *sk, u32 seq, u64 rcd_sn)
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
@@ -146,7 +146,6 @@ int tls_push_sg(struct sock *sk,
 	}
 
 	ctx->in_tcp_sendpages = false;
-	ctx->sk_write_space(sk);
 
 	return 0;
 }
@@ -228,6 +227,8 @@ static void tls_write_space(struct sock *sk)
 	else
 #endif
 		tls_sw_write_space(sk, ctx);
+
+	ctx->sk_write_space(sk);
 }
 
 static void tls_ctx_free(struct tls_context *ctx)

Original file line number	Diff line number	Diff line change
`@@ -558,9 +558,6 @@ void tls_device_write_space(struct sock sk, struct tls_context ctx)`
`558`	`558`	`MSG_DONTWAIT \| MSG_NOSIGNAL);`
`559`	`559`	`sk->sk_allocation = sk_allocation;`
`560`	`560`	`}`
`561`		`-`
`562`		`- if (!rc)`
`563`		`- ctx->sk_write_space(sk);`
`564`	`561`	`}`
`565`	`562`
`566`	`563`	`void handle_device_resync(struct sock *sk, u32 seq, u64 rcd_sn)`
Original file line number	Diff line number	Diff line change
`@@ -146,7 +146,6 @@ int tls_push_sg(struct sock *sk,`
`146`	`146`	`}`
`147`	`147`
`148`	`148`	`ctx->in_tcp_sendpages = false;`
`149`		`- ctx->sk_write_space(sk);`
`150`	`149`
`151`	`150`	`return 0;`
`152`	`151`	`}`
`@@ -228,6 +227,8 @@ static void tls_write_space(struct sock *sk)`
`228`	`227`	`else`
`229`	`228`	`#endif`
`230`	`229`	`tls_sw_write_space(sk, ctx);`
	`230`	`+`
	`231`	`+ ctx->sk_write_space(sk);`
`231`	`232`	`}`
`232`	`233`
`233`	`234`	`static void tls_ctx_free(struct tls_context *ctx)`