linux-kernel - Re: [PATCH v10 6/7] PCI: Unify wait for link active into generic pci

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Date:   Fri, 23 Feb 2018 12:23:30 +0530
From:   poza@...eaurora.org
To:     Christoph Hellwig <hch@...radead.org>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        Dongdong Liu <liudongdong3@...wei.com>,
        Keith Busch <keith.busch@...el.com>, Wei Zhang <wzhang@...com>,
        Sinan Kaya <okaya@...eaurora.org>,
        Timur Tabi <timur@...eaurora.org>
Subject: Re: [PATCH v10 6/7] PCI: Unify wait for link active into generic pci

On 2018-02-23 00:13, Christoph Hellwig wrote:
>> 
>> +/**
>> + * pci__wait_for_link - Wait for link till its active/inactive
> 
> typo - just wants a single underscore.
> 
>> +	pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
>> +	ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
> 
> no need for the !! when assigning to a boolean.

bool is 8 bit, while
#define  PCI_EXP_LNKSTA_DLLLA	0x2000	/* Data Link Layer Link Active */
so I think we need it. otherwise it will treat lnk_status & 
PCI_EXP_LNKSTA_DLLLA as 0 even if 13th bit is set.

> 
>> +
>> +	while ((ret != active) && (timeout > 0)) {
> 
> No need for either pair of inner braces.
> 
>> +		msleep(10);
>> +		timeout -= 10;
>> +		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
>> +		ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
> 
> Same as above.
> 
>> +	}
>> +
>> +	if (ret == active)
>> +		return true;
> 
> Seems like the structure is a bit odd.  Why not:
> 
> 	for (;;) {
> 		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
> 		if ((lnk_status & PCI_EXP_LNKSTA_DLLLA) == active)
> 			return true;
> 		if (timeout <= 0)
> 			break;
> 		timeout -= 10;
> 	}

Thanks for suggestion, will do this way. thanks.
Regards,
Oza.