Commit 48610ec2 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

usb-storage: reject probe of device one non-DMA HCDs when using highmem 



usb-storage is the last user of the block layer bounce buffering now,
and only uses it for HCDs that do not support DMA on highmem configs.

Remove this support and fail the probe so that the block layer bounce
buffering can go away.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250505081138.3435992-5-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 27a0918d

drivers/usb/storage/usb.c

+14 −6
Original line number Diff line number Diff line
@@ -1056,13 +1056,20 @@ int usb_stor_probe1(struct us_data **pus, 
		goto BadDevice;



	/*

	 * Some USB host controllers can't do DMA; they have to use PIO.

	 * For such controllers we need to make sure the block layer sets

	 * up bounce buffers in addressable memory.

	 * Some USB host controllers can't do DMA: They have to use PIO, or they

	 * have to use a small dedicated local memory area, or they have other

	 * restrictions on addressable memory.

	 *

	 * We can't support these controllers on highmem systems as we don't

	 * kmap or bounce buffer.

	 */

	if (!hcd_uses_dma(bus_to_hcd(us->pusb_dev->bus)) ||

	    bus_to_hcd(us->pusb_dev->bus)->localmem_pool)

		host->no_highmem = true;

	if (IS_ENABLED(CONFIG_HIGHMEM) &&

	    (!hcd_uses_dma(bus_to_hcd(us->pusb_dev->bus)) ||

	     bus_to_hcd(us->pusb_dev->bus)->localmem_pool)) {

		dev_warn(&intf->dev, "USB Mass Storage not supported on this host controller\n");

		result = -EINVAL;

		goto release;

	}



	/* Get the unusual_devs entries and the descriptors */

	result = get_device_info(us, id, unusual_dev);
@@ -1081,6 +1088,7 @@ int usb_stor_probe1(struct us_data **pus, 


BadDevice:

	usb_stor_dbg(us, "storage_probe() failed\n");

release:

	release_everything(us);

	return result;

}