From: Sekhar Nori <nsekhar@ti.com> To: Grygorii Strashko <grygorii.strashko@ti.com> Cc: "David S . Miller" <davem@davemloft.net>, <linux-omap@vger.kernel.org>, <netdev@vger.kernel.org> Subject: [PATCH net-next] drivers: net: davinci_mdio: prevent sprious timeout Date: Tue, 8 May 2018 13:56:38 +0530 [thread overview] Message-ID: <20180508082638.5707-1-nsekhar@ti.com> (raw) A well timed kernel preemption in the time_after() loop in wait_for_idle() can result in a spurious timeout error to be returned. Fix it by checking for status of hardware before returning timeout error. Signed-off-by: Sekhar Nori <nsekhar@ti.com> --- The issue has not been personally observed by me, but has been reported by users. Sending for next-next given the non-critical nature. There is seems to be no easy way to reproduce this. drivers/net/ethernet/ti/davinci_mdio.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/ti/davinci_mdio.c b/drivers/net/ethernet/ti/davinci_mdio.c index 3c33f4504d8e..4fbd04fd38cf 100644 --- a/drivers/net/ethernet/ti/davinci_mdio.c +++ b/drivers/net/ethernet/ti/davinci_mdio.c @@ -231,10 +231,16 @@ static inline int wait_for_idle(struct davinci_mdio_data *data) while (time_after(timeout, jiffies)) { if (__raw_readl(®s->control) & CONTROL_IDLE) - return 0; + goto out; } - dev_err(data->dev, "timed out waiting for idle\n"); - return -ETIMEDOUT; + + if (!(__raw_readl(®s->control) & CONTROL_IDLE)) { + dev_err(data->dev, "timed out waiting for idle\n"); + return -ETIMEDOUT; + } + +out: + return 0; } static int davinci_mdio_read(struct mii_bus *bus, int phy_id, int phy_reg) -- 2.16.2
WARNING: multiple messages have this Message-ID (diff)
From: Sekhar Nori <nsekhar@ti.com> To: Grygorii Strashko <grygorii.strashko@ti.com> Cc: "David S . Miller" <davem@davemloft.net>, linux-omap@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH net-next] drivers: net: davinci_mdio: prevent sprious timeout Date: Tue, 8 May 2018 13:56:38 +0530 [thread overview] Message-ID: <20180508082638.5707-1-nsekhar@ti.com> (raw) A well timed kernel preemption in the time_after() loop in wait_for_idle() can result in a spurious timeout error to be returned. Fix it by checking for status of hardware before returning timeout error. Signed-off-by: Sekhar Nori <nsekhar@ti.com> --- The issue has not been personally observed by me, but has been reported by users. Sending for next-next given the non-critical nature. There is seems to be no easy way to reproduce this. drivers/net/ethernet/ti/davinci_mdio.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/ti/davinci_mdio.c b/drivers/net/ethernet/ti/davinci_mdio.c index 3c33f4504d8e..4fbd04fd38cf 100644 --- a/drivers/net/ethernet/ti/davinci_mdio.c +++ b/drivers/net/ethernet/ti/davinci_mdio.c @@ -231,10 +231,16 @@ static inline int wait_for_idle(struct davinci_mdio_data *data) while (time_after(timeout, jiffies)) { if (__raw_readl(®s->control) & CONTROL_IDLE) - return 0; + goto out; } - dev_err(data->dev, "timed out waiting for idle\n"); - return -ETIMEDOUT; + + if (!(__raw_readl(®s->control) & CONTROL_IDLE)) { + dev_err(data->dev, "timed out waiting for idle\n"); + return -ETIMEDOUT; + } + +out: + return 0; } static int davinci_mdio_read(struct mii_bus *bus, int phy_id, int phy_reg) -- 2.16.2
next reply other threads:[~2018-05-08 8:26 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-05-08 8:26 Sekhar Nori [this message] 2018-05-08 8:26 ` [PATCH net-next] drivers: net: davinci_mdio: prevent sprious timeout Sekhar Nori 2018-05-08 12:48 ` Andrew Lunn 2018-05-09 10:44 ` Sekhar Nori 2018-05-09 10:44 ` Sekhar Nori
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