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USB: Add URB_FREE_BUFFER flag and the logic behind it

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USB: Add URB_FREE_BUFFER flag for freeing the transfer buffer

In some cases it is not needed that the driver keeps track of the
transfer buffer of an URB. It can be simply freed along with the
URB itself when the reference count goes down to zero. The new
flag URB_FREE_BUFFER enables this behavior.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Marcel Holtmann 2007-06-13 08:02:11 +02:00 committed by Greg Kroah-Hartman
parent 300871cd96
commit 8b3b01c898
2 changed files with 4 additions and 0 deletions
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3
drivers/usb/core/urb.c
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@ -13,6 +13,9 @@ static void urb_destroy(struct kref *kref)
{
struct urb *urb = to_urb(kref);
if (urb->transfer_flags & URB_FREE_BUFFER)
kfree(urb->transfer_buffer);
kfree(urb);
}

1
include/linux/usb.h
View File

@ -994,6 +994,7 @@ extern int usb_disabled(void);
#define URB_ZERO_PACKET 0x0040 /* Finish bulk OUT with short packet */
#define URB_NO_INTERRUPT 0x0080 /* HINT: no non-error interrupt
* needed */
#define URB_FREE_BUFFER 0x0100 /* Free transfer buffer with the URB */
struct usb_iso_packet_descriptor {
unsigned int offset;