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Commit b9039a2a authored by Gerrit Renker's avatar Gerrit Renker Committed by David S. Miller
Browse files

[DCCP] ccid3: Replace scaled division operations 



This replaces the remaining uses of usecs_div with scaled_div32, which
internally uses 64bit division and produces a warning on overflow.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: default avatarIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@mandriva.com>
parent 1a21e49a

net/dccp/ccids/ccid3.c

+3 −24
Original line number Diff line number Diff line
@@ -41,27 +41,6 @@ 
#include "lib/tfrc.h"

#include "ccid3.h"



/*

 * Reason for maths here is to avoid 32 bit overflow when a is big.

 * With this we get close to the limit.

 */

static u32 usecs_div(const u32 a, const u32 b)

{

	const u32 div = a < (UINT_MAX / (USEC_PER_SEC /    10)) ?    10 :

			a < (UINT_MAX / (USEC_PER_SEC /    50)) ?    50 :

			a < (UINT_MAX / (USEC_PER_SEC /   100)) ?   100 :

			a < (UINT_MAX / (USEC_PER_SEC /   500)) ?   500 :

			a < (UINT_MAX / (USEC_PER_SEC /  1000)) ?  1000 :

			a < (UINT_MAX / (USEC_PER_SEC /  5000)) ?  5000 :

			a < (UINT_MAX / (USEC_PER_SEC / 10000)) ? 10000 :

			a < (UINT_MAX / (USEC_PER_SEC / 50000)) ? 50000 :

								 100000;

	const u32 tmp = a * (USEC_PER_SEC / div);

	return (b >= 2 * div) ? tmp / (b / div) : tmp;

}







#ifdef CONFIG_IP_DCCP_CCID3_DEBUG

static int ccid3_debug;

#define ccid3_pr_debug(format, a...)	DCCP_PR_DEBUG(ccid3_debug, format, ##a)
@@ -731,8 +710,8 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk) 
	case TFRC_RSTATE_DATA: {

		const u32 delta = timeval_delta(&now,

					&hcrx->ccid3hcrx_tstamp_last_feedback);

		hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,

						   delta);

		hcrx->ccid3hcrx_x_recv =

			scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);

	}

		break;

	case TFRC_RSTATE_TERM:
@@ -862,7 +841,7 @@ static u32 ccid3_hc_rx_calc_first_li(struct sock *sk) 


	dccp_timestamp(sk, &tstamp);

	delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);

	x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta);

	x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);



	if (x_recv == 0)

		x_recv = hcrx->ccid3hcrx_x_recv;