[PATCH net-next] net/tls: Do not call msg_data_left() twice

[PATCH net-next] net/tls: Do not call msg_data_left() twice

[Vakul Garg]

In function tls_sw_sendmsg(), msg_data_left() needs to be called only
once. The second invocation of msg_data_left() for assigning variable
try_to_copy can be removed and merged with the first one.

Signed-off-by: Vakul Garg <vakul.garg@nxp.com>
---
 net/tls/tls_sw.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 0c2d029c9d4c..fd51ce65b99c 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -377,7 +377,7 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 			goto send_end;
 	}
 
-	while (msg_data_left(msg)) {
+	while ((try_to_copy = msg_data_left(msg))) {
 		if (sk->sk_err) {
 			ret = -sk->sk_err;
 			goto send_end;
@@ -385,7 +385,6 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 
 		orig_size = ctx->sg_plaintext_size;
 		full_record = false;
-		try_to_copy = msg_data_left(msg);
 		record_room = TLS_MAX_PAYLOAD_SIZE - ctx->sg_plaintext_size;
 		if (try_to_copy >= record_room) {
 			try_to_copy = record_room;
-- 
2.13.6

Re: [PATCH net-next] net/tls: Do not call msg_data_left() twice

[Al Viro]

On Tue, Jul 24, 2018 at 04:41:18PM +0530, Vakul Garg wrote:
> In function tls_sw_sendmsg(), msg_data_left() needs to be called only
> once. The second invocation of msg_data_left() for assigning variable
> try_to_copy can be removed and merged with the first one.

You do realize that msg_data_left(msg) is simply msg->msg_iter.count?
So I'm not at all sure that your change will be an overall win...

Re: [PATCH net-next] net/tls: Do not call msg_data_left() twice

[Vakul Garg]

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From: Al Viro
Sent: Wednesday, 25 July, 7:19 AM
Subject: Re: [PATCH net-next] net/tls: Do not call msg_data_left() twice
To: Vakul Garg
Cc: netdev@vger.kernel.org, borisp@mellanox.com, aviadye@mellanox.com, davejwatson@fb.com, davem@davemloft.net


On Tue, Jul 24, 2018 at 04:41:18PM +0530, Vakul Garg wrote: > In function tls_sw_sendmsg(), msg_data_left() needs to be called only > once. The second invocation of msg_data_left() for assigning variable > try_to_copy can be removed and merged with the first one. You do realize that msg_data_left(msg) is simply msg->msg_iter.count? So I'm not at all sure that your change will be an overall win...

Agreed, msg_data_left is inexpensive. It's just that is pointless to call it again.


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