netdev - Re: [PATCH net-next] bnxt: Detach page from page pool before sending up the stack

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Message-ID: <20200110021915.GA13304@C02YVCJELVCG>
Date:   Thu, 9 Jan 2020 21:19:15 -0500
From:   Andy Gospodarek <andrew.gospodarek@...adcom.com>
To:     Jonathan Lemon <jonathan.lemon@...il.com>
Cc:     netdev@...r.kernel.org, michael.chan@...adcom.com,
        davem@...emloft.net, kernel-team@...com
Subject: Re: [PATCH net-next] bnxt: Detach page from page pool before sending
 up the stack

On Thu, Jan 09, 2020 at 11:35:42AM -0800, Jonathan Lemon wrote:
> When running in XDP mode, pages come from the page pool, and should
> be freed back to the same pool or specifically detached.  Currently,
> when the driver re-initializes, the page pool destruction is delayed
> forever since it thinks there are oustanding pages.

If you can please share a reproduction script/steps that would be
helpful for me.

Since this is an XDP_PASS case I can easily create a program that does
that, so no need to share that program -- just the sequence to remove
the program, shutdown the driver, whatever is done and the error you
see.

Thanks!

> 
> Fixes: 322b87ca55f2 ("bnxt_en: add page_pool support")
> Signed-off-by: Jonathan Lemon <jonathan.lemon@...il.com>
> ---
>  drivers/net/ethernet/broadcom/bnxt/bnxt.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> index 39d4309b17fb..33eb8cd6551e 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> @@ -944,6 +944,7 @@ static struct sk_buff *bnxt_rx_page_skb(struct bnxt *bp,
>  	dma_addr -= bp->rx_dma_offset;
>  	dma_unmap_page_attrs(&bp->pdev->dev, dma_addr, PAGE_SIZE, bp->rx_dir,
>  			     DMA_ATTR_WEAK_ORDERING);
> +	page_pool_release_page(rxr->page_pool, page);
>  
>  	if (unlikely(!payload))
>  		payload = eth_get_headlen(bp->dev, data_ptr, len);
> -- 
> 2.17.1
>