From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932761AbdJKAqg (ORCPT ); Tue, 10 Oct 2017 20:46:36 -0400 Received: from omzsmtpe03.verizonbusiness.com ([199.249.25.208]:43859 "EHLO omzsmtpe03.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756520AbdJKAqc (ORCPT ); Tue, 10 Oct 2017 20:46:32 -0400 From: "Levin, Alexander (Sasha Levin)" X-Host: endeavour.tdc.vzwcorp.com To: "gregkh@linuxfoundation.org" CC: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [GIT PULL for-4.4 06/25] net/mlx4_en: fix overflow in mlx4_en_init_timestamp() Thread-Topic: [GIT PULL for-4.4 06/25] net/mlx4_en: fix overflow in mlx4_en_init_timestamp() Thread-Index: AQHTQipCgKHSCc8GHkqIryXdFKYNBw== Date: Wed, 11 Oct 2017 00:45:40 +0000 Message-ID: <20171011004533.8044-7-alexander.levin@verizon.com> References: <20171011004533.8044-1-alexander.levin@verizon.com> In-Reply-To: <20171011004533.8044-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v9B11SwK030420 From: Eric Dumazet [ Upstream commit 47d3a07528ecbbccf53bc4390d70b4e3d1c04fcf ] The cited commit makes a great job of finding optimal shift/multiplier values assuming a 10 seconds wrap around, but forgot to change the overflow_period computation. It overflows in cyclecounter_cyc2ns(), and the final result is 804 ms, which is silly. Lets simply use 5 seconds, no need to recompute this, given how it is supposed to work. Later, we will use a timer instead of a work queue, since the new RX allocation schem will no longer need mlx4_en_recover_from_oom() and the service_task firing every 250 ms. Fixes: 31c128b66e5b ("net/mlx4_en: Choose time-stamping shift value according to HW frequency") Signed-off-by: Eric Dumazet Cc: Tariq Toukan Cc: Eugenia Emantayev Reviewed-by: Tariq Toukan Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/mellanox/mlx4/en_clock.c | 18 ++++++++---------- drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 - 2 files changed, 8 insertions(+), 11 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c index 1494997c4f7e..4dccf7287f0f 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c @@ -88,10 +88,17 @@ void mlx4_en_remove_timestamp(struct mlx4_en_dev *mdev) } } +#define MLX4_EN_WRAP_AROUND_SEC 10UL +/* By scheduling the overflow check every 5 seconds, we have a reasonably + * good chance we wont miss a wrap around. + * TOTO: Use a timer instead of a work queue to increase the guarantee. + */ +#define MLX4_EN_OVERFLOW_PERIOD (MLX4_EN_WRAP_AROUND_SEC * HZ / 2) + void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev) { bool timeout = time_is_before_jiffies(mdev->last_overflow_check + - mdev->overflow_period); + MLX4_EN_OVERFLOW_PERIOD); unsigned long flags; if (timeout) { @@ -236,7 +243,6 @@ static const struct ptp_clock_info mlx4_en_ptp_clock_info = { .enable = mlx4_en_phc_enable, }; -#define MLX4_EN_WRAP_AROUND_SEC 10ULL /* This function calculates the max shift that enables the user range * of MLX4_EN_WRAP_AROUND_SEC values in the cycles register. @@ -258,7 +264,6 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev) { struct mlx4_dev *dev = mdev->dev; unsigned long flags; - u64 ns, zero = 0; /* mlx4_en_init_timestamp is called for each netdev. * mdev->ptp_clock is common for all ports, skip initialization if @@ -282,13 +287,6 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev) ktime_to_ns(ktime_get_real())); write_unlock_irqrestore(&mdev->clock_lock, flags); - /* Calculate period in seconds to call the overflow watchdog - to make - * sure counter is checked at least once every wrap around. - */ - ns = cyclecounter_cyc2ns(&mdev->cycles, mdev->cycles.mask, zero, &zero); - do_div(ns, NSEC_PER_SEC / 2 / HZ); - mdev->overflow_period = ns; - /* Configure the PHC */ mdev->ptp_clock_info = mlx4_en_ptp_clock_info; snprintf(mdev->ptp_clock_info.name, 16, "mlx4 ptp"); diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h index c41f15102ae0..10aa6544cf4d 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h @@ -409,7 +409,6 @@ struct mlx4_en_dev { struct cyclecounter cycles; struct timecounter clock; unsigned long last_overflow_check; - unsigned long overflow_period; struct ptp_clock *ptp_clock; struct ptp_clock_info ptp_clock_info; struct notifier_block nb; -- 2.11.0