On Fri. 10 juin 2022 à 06:11, Rhett Aultman <rhett.aultman@xxxxxxxxxxx> wrote: The From tag goes at the beginning of the patch. From: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx> > When allocating URB memory with kmalloc(), drivers can simply set the > URB_FREE_BUFFER flag in urb::transfer_flags and that way, the memory > will be freed in the background when killing the URB (for example with > usb_kill_anchored_urbs()). > > However, there are no equivalent mechanism when allocating DMA memory > (with usb_alloc_coherent()). > > This patch adds a new flag: URB_FREE_COHERENT. Setting this flag will > cause the kernel to automatically call usb_free_coherent() on the > transfer buffer when the URB is killed, similarly to how > URB_FREE_BUFFER triggers a call to kfree(). > > In order to have all the flags in numerical order, URB_DIR_IN is > renumbered from 0x0200 to 0x0400 so that URB_FREE_COHERENT can reuse > value 0x0200. > > From: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx> Move the From tag from here to the first line. > Signed-off-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx> > --- > drivers/usb/core/urb.c | 3 +++ > include/linux/usb.h | 3 ++- > 2 files changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c > index 33d62d7e3929..1460fdac0b18 100644 > --- a/drivers/usb/core/urb.c > +++ b/drivers/usb/core/urb.c > @@ -22,6 +22,9 @@ static void urb_destroy(struct kref *kref) > > if (urb->transfer_flags & URB_FREE_BUFFER) > kfree(urb->transfer_buffer); > + else if (urb->transfer_flags & URB_FREE_COHERENT) > + usb_free_coherent(urb->dev, urb->transfer_buffer_length, > + urb->transfer_buffer, urb->transfer_dma); > > kfree(urb); > } > diff --git a/include/linux/usb.h b/include/linux/usb.h > index 60bee864d897..945d68ea1d76 100644 > --- a/include/linux/usb.h > +++ b/include/linux/usb.h > @@ -1328,9 +1328,10 @@ extern int usb_disabled(void); > #define URB_NO_INTERRUPT 0x0080 /* HINT: no non-error interrupt > * needed */ > #define URB_FREE_BUFFER 0x0100 /* Free transfer buffer with the URB */ > +#define URB_FREE_COHERENT 0x0200 /* Free DMA memory of transfer buffer */ > > /* The following flags are used internally by usbcore and HCDs */ > -#define URB_DIR_IN 0x0200 /* Transfer from device to host */ > +#define URB_DIR_IN 0x0400 /* Transfer from device to host */ > #define URB_DIR_OUT 0 > #define URB_DIR_MASK URB_DIR_IN
