From 31fe084ffaaf8abece14f8ca28e5e3b4e2bf97b6 Mon Sep 17 00:00:00 2001 From: Jack Pham Date: Tue, 1 Aug 2017 02:00:56 -0700 Subject: [PATCH] usb: gadget: core: unmap request from DMA only if previously mapped In the SG case this is already handled since a non-zero request->num_mapped_sgs is a clear indicator that dma_map_sg() had been called. While it would be nice to do the same for the singly mapped case by simply checking for non-zero request->dma, it's conceivable that 0 is a valid dma_addr_t handle. Hence add a flag 'dma_mapped' to struct usb_request and use this to determine the need to call dma_unmap_single(). Otherwise, if a request is not DMA mapped then the result of calling usb_request_unmap_request() would safely be a no-op. Signed-off-by: Jack Pham Signed-off-by: Felipe Balbi --- drivers/usb/gadget/udc/core.c | 5 ++++- include/linux/usb/gadget.h | 2 ++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index e6f04eee95c4..c1cef6a11ecb 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -812,6 +812,8 @@ int usb_gadget_map_request_by_dev(struct device *dev, dev_err(dev, "failed to map buffer\n"); return -EFAULT; } + + req->dma_mapped = 1; } return 0; @@ -836,9 +838,10 @@ void usb_gadget_unmap_request_by_dev(struct device *dev, is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE); req->num_mapped_sgs = 0; - } else { + } else if (req->dma_mapped) { dma_unmap_single(dev, req->dma, req->length, is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE); + req->dma_mapped = 0; } } EXPORT_SYMBOL_GPL(usb_gadget_unmap_request_by_dev); diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index 1a4a4bacfae6..21468a722c4a 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -48,6 +48,7 @@ struct usb_ep; * by adding a zero length packet as needed; * @short_not_ok: When reading data, makes short packets be * treated as errors (queue stops advancing till cleanup). + * @dma_mapped: Indicates if request has been mapped to DMA (internal) * @complete: Function called when request completes, so this request and * its buffer may be re-used. The function will always be called with * interrupts disabled, and it must not sleep. @@ -103,6 +104,7 @@ struct usb_request { unsigned no_interrupt:1; unsigned zero:1; unsigned short_not_ok:1; + unsigned dma_mapped:1; void (*complete)(struct usb_ep *ep, struct usb_request *req); -- 2.45.2