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From: Neal Liu <neal_liu@aspeedtech.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Felipe Balbi <balbi@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Joel Stanley <joel@jms.id.au>, Andrew Jeffery <andrew@aj.id.au>,
	"linux-aspeed@lists.ozlabs.org" <linux-aspeed@lists.ozlabs.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"kernel-janitors@vger.kernel.org"
	<kernel-janitors@vger.kernel.org>
Subject: RE: [PATCH] usb: gadget: aspeed_udc: fix handling of tx_len == 0
Date: Thu, 23 Jun 2022 01:41:49 +0000	[thread overview]
Message-ID: <HK0PR06MB32023259EBD6B4C649C62E8280B59@HK0PR06MB3202.apcprd06.prod.outlook.com> (raw)
In-Reply-To: <YrMsU9HvdBm5YrRH@kili>

> The bug is that we should still enter this loop if "tx_len" is zero.
> 
> After adding the "last" variable, then the "chunk >= 0" condition is no longer
> required but I left it for readability.
> 

Use either "chunk >=0" or "last".
I think the former is more simpler.

> Reported-by: Neal Liu <neal_liu@aspeedtech.com>
> Fixes: c09b1f372e74 ("usb: gadget: aspeed_udc: cleanup loop in
> ast_dma_descriptor_setup()")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>  drivers/usb/gadget/udc/aspeed_udc.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/aspeed_udc.c
> b/drivers/usb/gadget/udc/aspeed_udc.c
> index d75a4e070bf7..01968e2167f9 100644
> --- a/drivers/usb/gadget/udc/aspeed_udc.c
> +++ b/drivers/usb/gadget/udc/aspeed_udc.c
> @@ -476,6 +476,7 @@ static int ast_dma_descriptor_setup(struct ast_udc_ep
> *ep, u32 dma_buf,  {
>  	struct ast_udc_dev *udc = ep->udc;
>  	struct device *dev = &udc->pdev->dev;
> +	bool last = false;
>  	int chunk, count;
>  	u32 offset;
> 
> @@ -493,14 +494,16 @@ static int ast_dma_descriptor_setup(struct
> ast_udc_ep *ep, u32 dma_buf,
>  	       "tx_len", tx_len);
> 
>  	/* Create Descriptor Lists */
> -	while (chunk > 0 && count < AST_UDC_DESCS_COUNT) {
> +	while (chunk >= 0 && !last && count < AST_UDC_DESCS_COUNT) {
> 
>  		ep->descs[ep->descs_wptr].des_0 = dma_buf + offset;
> 
> -		if (chunk > ep->chunk_max)
> +		if (chunk > ep->chunk_max) {
>  			ep->descs[ep->descs_wptr].des_1 = ep->chunk_max;
> -		else
> +		} else {
>  			ep->descs[ep->descs_wptr].des_1 = chunk;
> +			last = true;
> +		}
> 
>  		chunk -= ep->chunk_max;
> 
> --
> 2.35.1


  reply	other threads:[~2022-06-23  1:42 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-22 14:50 [PATCH] usb: gadget: aspeed_udc: fix handling of tx_len == 0 Dan Carpenter
2022-06-23  1:41 ` Neal Liu [this message]
2022-06-23  6:43   ` Dan Carpenter
2022-06-23  7:22     ` Dan Carpenter
2022-06-23  7:52       ` Neal Liu
2022-06-23  7:55         ` Dan Carpenter
2022-06-23  8:37           ` Neal Liu
2022-06-24  6:17     ` Herrenschmidt, Benjamin
2022-06-24  6:34       ` Dan Carpenter
2022-06-24  6:39         ` Benjamin Herrenschmidt
2022-06-24  7:46           ` Neal Liu
2022-06-27  1:30             ` Benjamin Herrenschmidt
2022-06-28  7:17               ` Neal Liu

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