linux-kernel - RE: [PATCH] PCI: dwc: designware: don't sleep in atomic context

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Date:   Thu, 12 Oct 2017 10:39:39 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Pankaj Dubey' <pankaj.dubey@...sung.com>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Kishon Vijay Abraham I <kishon@...com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Joao Pinto <Joao.Pinto@...opsys.com>
Subject: RE: [PATCH] PCI: dwc: designware: don't sleep in atomic context

From: Pankaj Dubey
> Sent: 12 October 2017 08:55
> In pcie-designware.c many places we are calling "usleep_range" which
> are in atomic context. This patch fixes these potential BUGs and
> replaces "usleep_range" with mdelay calls.
> 
> Signed-off-by: Pankaj Dubey <pankaj.dubey@...sung.com>
> ---
>  drivers/pci/dwc/pcie-designware.c | 8 ++++----
>  drivers/pci/dwc/pcie-designware.h | 3 +--
>  2 files changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/dwc/pcie-designware.c b/drivers/pci/dwc/pcie-designware.c
> index 88abddd..35d19b9 100644
> --- a/drivers/pci/dwc/pcie-designware.c
> +++ b/drivers/pci/dwc/pcie-designware.c
> @@ -138,7 +138,7 @@ static void dw_pcie_prog_outbound_atu_unroll(struct dw_pcie *pci, int index,
>  		if (val & PCIE_ATU_ENABLE)
>  			return;
> 
> -		usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
> +		mdelay(LINK_WAIT_IATU_MIN);
>  	}

Spinning for 9ms (possibly 10 times) isn't really a good idea.

	David