Hi Frank, Le vendredi 19 janvier 2024 à 16:49 -0500, Frank Li a écrit : > On Wed, Jan 17, 2024 at 01:26:43PM +0100, Paul Cercueil wrote: > > Add a new 'sg_was_mapped' field to the struct usb_request. This > > field > > can be used to indicate that the scatterlist associated to the USB > > transfer has already been mapped into the DMA space, and it does > > not > > have to be done internally. > > > > Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx> > > --- > > drivers/usb/gadget/udc/core.c | 7 ++++++- > > include/linux/usb/gadget.h | 2 ++ > > 2 files changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/usb/gadget/udc/core.c > > b/drivers/usb/gadget/udc/core.c > > index d59f94464b87..9d4150124fdb 100644 > > --- a/drivers/usb/gadget/udc/core.c > > +++ b/drivers/usb/gadget/udc/core.c > > @@ -903,6 +903,11 @@ int usb_gadget_map_request_by_dev(struct > > device *dev, > > if (req->length == 0) > > return 0; > > > > + if (req->sg_was_mapped) { > > + req->num_mapped_sgs = req->num_sgs; > > + return 0; > > + } > > + > > if (req->num_sgs) { > > int mapped; > > > > @@ -948,7 +953,7 @@ EXPORT_SYMBOL_GPL(usb_gadget_map_request); > > void usb_gadget_unmap_request_by_dev(struct device *dev, > > struct usb_request *req, int is_in) > > { > > - if (req->length == 0) > > + if (req->length == 0 || req->sg_was_mapped) > > return; > > > > if (req->num_mapped_sgs) { > > diff --git a/include/linux/usb/gadget.h > > b/include/linux/usb/gadget.h > > index a771ccc038ac..c529e4e06997 100644 > > --- a/include/linux/usb/gadget.h > > +++ b/include/linux/usb/gadget.h > > @@ -52,6 +52,7 @@ struct usb_ep; > > * @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) > > + * @sg_was_mapped: Set if the scatterlist has been mapped before > > the request > > * @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. > > @@ -111,6 +112,7 @@ struct usb_request { > > unsigned zero:1; > > unsigned short_not_ok:1; > > unsigned dma_mapped:1; > > + unsigned sg_was_mapped:1; > > why not use dma_mapped direclty? Because of the unmap case. We want to know whether we should unmap or not. > > Frank Cheers, -Paul > > > > > void (*complete)(struct usb_ep *ep, > > struct usb_request *req); > > -- > > 2.43.0 > >