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Commit e92b17c3 authored by Chandana Kishori Chiluveru's avatar Chandana Kishori Chiluveru Committed by Gerrit - the friendly Code Review server
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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.

Change-Id: Ibb00d6df31f21522da9ebbcda3ae288cb7b189fa
Signed-off-by: default avatarJack Pham <jackp@codeaurora.org>
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
Git-commit: 31fe084ffaaf8abece14f8ca28e5e3b4e2bf97b6
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[cchiluve@codeaurora.org: resolve trivial merge conflicts]
Signed-off-by: default avatarChandana Kishori Chiluveru <cchiluve@codeaurora.org>
parent 7d2cf5a4

drivers/usb/gadget/udc/core.c

+4 −1
Original line number Diff line number Diff line
@@ -857,6 +857,8 @@ 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;
@@ -881,9 +883,10 @@ void usb_gadget_unmap_request_by_dev(struct device *dev, 
				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);



		req->num_mapped_sgs = 0;

	} else if (req->dma != DMA_ERROR_CODE) {

	} 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);

include/linux/usb/gadget.h

+2 −0
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ struct gsi_channel_info { 
 *     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.
@@ -204,6 +205,7 @@ 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);