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Date: Tue, 22 Oct 2024 10:44:43 -0500
From: Bjorn Helgaas <helgaas@kernel.org>
To: Guixin Liu <kanie@linux.alibaba.com>
Cc: bhelgaas@google.com, linux-pci@vger.kernel.org,
	Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] PCI: optimize proc sequential file read
Message-ID: <20241022154443.GA880326@bhelgaas>
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In-Reply-To: <20241018054728.116519-1-kanie@linux.alibaba.com>

[+cc Greg]

On Fri, Oct 18, 2024 at 01:47:28PM +0800, Guixin Liu wrote:
> PCI driver will traverse pci device list in pci_seq_start in every
> sequential file reading, use xarry to store all pci devices to
> accelerate finding the start.

>  /* iterator */
>  static void *pci_seq_start(struct seq_file *m, loff_t *pos)
>  {
> -	struct pci_dev *dev = NULL;
> +	struct pci_dev *dev;
>  	loff_t n = *pos;
>  
> -	for_each_pci_dev(dev) {
> -		if (!n--)
> -			break;
> -	}

Maybe another approach would be to use pci_get_device() directly
instead of for_each_pci_dev().

pci_get_device() takes a "from" starting point, so instead of keeping
track of the index "n", you could keep track of the current pci_dev.