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Subject: Re: [PATCH] rtw88/pci: Rearrange the memory usage for skb in RX ISR
To:     Jian-Hong Pan <jian-hong@endlessm.com>,
        Yan-Hsuan Chuang <yhchuang@realtek.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S . Miller" <davem@davemloft.net>
Cc:     linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux@endlessm.com,
        Daniel Drake <drake@endlessm.com>, stable@vger.kernel.org
References: <20190708063252.4756-1-jian-hong@endlessm.com>
From:   Larry Finger <Larry.Finger@lwfinger.net>
Message-ID: <212a37b0-583b-1062-64fd-f0fb0d4f982f@lwfinger.net>
Date:   Mon, 8 Jul 2019 13:01:06 -0500
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On 7/8/19 1:32 AM, Jian-Hong Pan wrote:
> diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
> index cfe05ba7280d..1bfc99ae6b84 100644
> --- a/drivers/net/wireless/realtek/rtw88/pci.c
> +++ b/drivers/net/wireless/realtek/rtw88/pci.c
> @@ -786,6 +786,15 @@ static void rtw_pci_rx_isr(struct rtw_dev *rtwdev, struct rtw_pci *rtwpci,
>   		rx_desc = skb->data;
>   		chip->ops->query_rx_desc(rtwdev, rx_desc, &pkt_stat, &rx_status);
>   
> +		/* discard current skb if the new skb cannot be allocated as a
> +		 * new one in rx ring later
> +		 * */
> +		new = dev_alloc_skb(RTK_PCI_RX_BUF_SIZE);
> +		if (WARN(!new, "rx routine starvation\n")) {
> +			new = skb;
> +			goto next_rp;

This should probably be a WARN_ONCE() rather than WARN(), otherwise the logs 
will be flooded once this condition triggers.

Larry