]> www.infradead.org Git - users/jedix/linux-maple.git/commit
usb: dwc2: gadget: Don't write invalid mapped sg entries into dma_desc with iommu...
authorPeng Hongchi <hongchi.peng@siengine.com>
Thu, 23 May 2024 10:03:15 +0000 (18:03 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 4 Jun 2024 13:41:26 +0000 (15:41 +0200)
commit1134289b6b93d73721340b66c310fd985385e8fa
treecd1a4793e2f7ab6d200725c984c1792599abdc99
parentb50a2da03bd95784541b3f9058e452cc38f9ba05
usb: dwc2: gadget: Don't write invalid mapped sg entries into dma_desc with iommu enabled

When using dma_map_sg() to map the scatterlist with iommu enabled,
the entries in the scatterlist can be mergerd into less but longer
entries in the function __finalise_sg(). So that the number of
valid mapped entries is actually smaller than ureq->num_reqs,and
there are still some invalid entries in the scatterlist with
dma_addr=0xffffffff and len=0. Writing these invalid sg entries
into the dma_desc can cause a data transmission error.

The function dma_map_sg() returns the number of valid map entries
and the return value is assigned to usb_request::num_mapped_sgs in
function usb_gadget_map_request_by_dev(). So that just write valid
mapped entries into dma_desc according to the usb_request::num_mapped_sgs,
and set the IOC bit if it's the last valid mapped entry.

This patch poses no risk to no-iommu situation, cause
ureq->num_mapped_sgs equals ureq->num_sgs while using dma_direct_map_sg()
to map the scatterlist whith iommu disabled.

Signed-off-by: Peng Hongchi <hongchi.peng@siengine.com>
Link: https://lore.kernel.org/r/20240523100315.7226-1-hongchi.peng@siengine.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/dwc2/gadget.c