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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.

Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Jack Pham 2017-08-01 02:00:56 -07:00 committed by Felipe Balbi
parent f8faa3bf5f
commit 31fe084ffa
2 changed files with 6 additions and 1 deletions
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5
drivers/usb/gadget/udc/core.c
View File

@ -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);

2
include/linux/usb/gadget.h
View File

@ -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);