Re: [PATCH] USB: Fix incorrect DMA allocations for local memory pool drivers

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sat, Nov 30, 2019 at 05:50:55PM +0100, Fredrik Noring wrote:
> Fix commit 7b81cb6bddd2 ("usb: add a HCD_DMA flag instead of
> guestimating DMA capabilities") where local memory USB drivers
> erroneously allocate DMA memory instead of pool memory, causing
> 
> 	OHCI Unrecoverable Error, disabled
> 	HC died; cleaning up
> 
> The order between hcd_uses_dma() and hcd->localmem_pool is now
> arranged as in hcd_buffer_alloc() and hcd_buffer_free(), with the
> test for hcd->localmem_pool placed first.
> 
> As an alternative, one might consider adjusting hcd_uses_dma() with
> 
>  static inline bool hcd_uses_dma(struct usb_hcd *hcd)
>  {
> -	return IS_ENABLED(CONFIG_HAS_DMA) && (hcd->driver->flags & HCD_DMA);
> +	return IS_ENABLED(CONFIG_HAS_DMA) &&
> +		(hcd->driver->flags & HCD_DMA) &&
> +		(hcd->localmem_pool == NULL);
>  }
> 
> One can also consider unsetting HCD_DMA for local memory pool drivers.
> 
> Fixes: 7b81cb6bddd2 ("usb: add a HCD_DMA flag instead of guestimating DMA capabilities")
> Cc: stable <stable@vger.kernel.org>
> Signed-off-by: Fredrik Noring <noring@nocrew.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/usb/core/hcd.c         | 42 +++++++++++++++++-----------------
>  drivers/usb/storage/scsiglue.c |  3 ++-
>  2 files changed, 23 insertions(+), 22 deletions(-)

This patch doesn't apply against 5.5-rc1, can you refresh it and resend?

thanks,

greg k-h