From: Sam Day Date: Wed, 7 Jan 2026 22:30:21 +0000 (+1000) Subject: usb: gadget: f_fs: fix DMA-BUF OUT queues X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0145e7acd29855dfba4a2f387d455b5d9a520f0e;p=thirdparty%2Flinux.git usb: gadget: f_fs: fix DMA-BUF OUT queues Currently, DMA_FROM_DEVICE is used when attaching DMABUFs to IN endpoints and DMA_TO_DEVICE for OUT endpoints. This is inverted from how it should be. The result is IOMMU read-only mappings placed on OUT queues, triggering arm-smmu write faults. Put differently, OUT endpoints flow data from host -> gadget, meaning the UDC peripheral needs to have write access to the buffer to fill it with the incoming data. This commit flips the directions and updates the implicit-sync helpers so IN endpoints act as readers and OUT endpoints as writers. Signed-off-by: Sam Day Tested-by: David Heidelberg # OnePlus 6T on sdm845-next-20251119 Link: https://patch.msgid.link/20260108-ffs-dmabuf-ioctl-fix-v1-2-e51633891a81@samcday.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index c479d0204afb..c1826aa2f0f8 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1513,7 +1513,7 @@ static int ffs_dmabuf_attach(struct file *file, int fd) goto err_dmabuf_detach; } - dir = epfile->in ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + dir = epfile->in ? DMA_TO_DEVICE : DMA_FROM_DEVICE; err = ffs_dma_resv_lock(dmabuf, nonblock); if (err) @@ -1643,7 +1643,7 @@ static int ffs_dmabuf_transfer(struct file *file, /* Make sure we don't have writers */ timeout = nonblock ? 0 : msecs_to_jiffies(DMABUF_ENQUEUE_TIMEOUT_MS); retl = dma_resv_wait_timeout(dmabuf->resv, - dma_resv_usage_rw(epfile->in), + dma_resv_usage_rw(!epfile->in), true, timeout); if (retl == 0) retl = -EBUSY; @@ -1688,7 +1688,7 @@ static int ffs_dmabuf_transfer(struct file *file, dma_fence_init(&fence->base, &ffs_dmabuf_fence_ops, &priv->lock, priv->context, seqno); - resv_dir = epfile->in ? DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ; + resv_dir = epfile->in ? DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE; dma_resv_add_fence(dmabuf->resv, &fence->base, resv_dir); dma_resv_unlock(dmabuf->resv);