On Sun, 15 Apr 2018, Christoph Hellwig wrote: > USB host controllers now must handle highmem, so we can get rid of bounce > buffering highmem pages in the block layer.
Sorry, I don't quite understand what you are saying. Do you mean that all USB host controllers now magically _do_ handle highmem? Or do you mean that if they _don't_ handle highmem, we will not support them any more? Alan Stern > Signed-off-by: Christoph Hellwig <h...@lst.de> > --- > drivers/usb/storage/scsiglue.c | 9 --------- > 1 file changed, 9 deletions(-) > > diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c > index c267f2812a04..4e453d9d45d5 100644 > --- a/drivers/usb/storage/scsiglue.c > +++ b/drivers/usb/storage/scsiglue.c > @@ -130,15 +130,6 @@ static int slave_configure(struct scsi_device *sdev) > blk_queue_max_hw_sectors(sdev->request_queue, 2048); > } > > - /* > - * Some USB host controllers can't do DMA; they have to use PIO. > - * They indicate this by setting their dma_mask to NULL. For > - * such controllers we need to make sure the block layer sets > - * up bounce buffers in addressable memory. > - */ > - if (!us->pusb_dev->bus->controller->dma_mask) > - blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_HIGH); > - > /* > * We can't put these settings in slave_alloc() because that gets > * called before the device type is known. Consequently these >