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SubjectRE: [PATCH] usb: gadget: mv_udc: use GFP_ATOMIC in build_dtd()
Hi Alexey,
> -----Original Message-----
> From: Alexey Khoroshilov [mailto:khoroshilov@ispras.ru]
> Sent: 2012年7月6日 7:10
> To: Neil Zhang; Felipe Balbi
> Cc: Alexey Khoroshilov; Greg Kroah-Hartman; linux-usb@vger.kernel.org;
> linux-kernel@vger.kernel.org; ldv-project@ispras.ru
> Subject: [PATCH] usb: gadget: mv_udc: use GFP_ATOMIC in build_dtd()
>
> build_dtd() is called either from interrupt handler mv_udc_irq()
> or with spinlock held (from mv_ep_queue()). So we should
> alloc memory with GFP_ATOMIC, not GFP_KERNEL.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
> ---
> drivers/usb/gadget/mv_udc_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/gadget/mv_udc_core.c
> b/drivers/usb/gadget/mv_udc_core.c
> index 117a4bb..693e1e4 100644
> --- a/drivers/usb/gadget/mv_udc_core.c
> +++ b/drivers/usb/gadget/mv_udc_core.c
> @@ -374,7 +374,7 @@ static struct mv_dtd *build_dtd(struct mv_req *req,
> unsigned *length,
> * Be careful that no _GFP_HIGHMEM is set,
> * or we can not use dma_to_virt
> */
> - dtd = dma_pool_alloc(udc->dtd_pool, GFP_KERNEL, dma);
> + dtd = dma_pool_alloc(udc->dtd_pool, GFP_ATOMIC, dma);
> if (dtd == NULL)
> return dtd;
>
> --
> 1.7.9.5

Thanks for your finding.
Actually we have found the issue some months ago and I would like to add some error handler if it failed to alloc memory.
I will sent out the patches soon.
Thanks.

Best Regards,
Neil Zhang
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