linux-kernel - [PATCH 4.4 176/210] mmc: sdhci: fix data timeout (part 2)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20160410183532.888360212@linuxfoundation.org>
Date:	Sun, 10 Apr 2016 11:36:37 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Russell King <rmk+kernel@....linux.org.uk>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Gregory CLEMENT <gregory.clement@...e-electrons.com>,
	Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH 4.4 176/210] mmc: sdhci: fix data timeout (part 2)

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Russell King <rmk+kernel@....linux.org.uk>

commit 7f05538af71c7d30b5fc821cbe9f318edc645961 upstream.

The calculation for the timeout based on the number of card clocks is
incorrect.  The calculation assumed:

	timeout in microseconds = clock cycles / clock in Hz

which is clearly a several orders of magnitude wrong.  Fix this by
multiplying the clock cycles by 1000000 prior to dividing by the Hz
based clock.  Also, as per part 1, ensure that the division rounds
up.

As this needs 64-bit math via do_div(), avoid it if the clock cycles
is zero.

Signed-off-by: Russell King <rmk+kernel@....linux.org.uk>
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Tested-by: Gregory CLEMENT <gregory.clement@...e-electrons.com>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/mmc/host/sdhci.c |   15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -667,8 +667,19 @@ static u8 sdhci_calc_timeout(struct sdhc
 		target_timeout = cmd->busy_timeout * 1000;
 	else {
 		target_timeout = DIV_ROUND_UP(data->timeout_ns, 1000);
-		if (host->clock)
-			target_timeout += data->timeout_clks / host->clock;
+		if (host->clock && data->timeout_clks) {
+			unsigned long long val;
+
+			/*
+			 * data->timeout_clks is in units of clock cycles.
+			 * host->clock is in Hz.  target_timeout is in us.
+			 * Hence, us = 1000000 * cycles / Hz.  Round up.
+			 */
+			val = 1000000 * data->timeout_clks;
+			if (do_div(val, host->clock))
+				target_timeout++;
+			target_timeout += val;
+		}
 	}
 
 	/*