At Wed, 7 Apr 2010 19:59:35 +0200, Daniel Mack wrote: > > On Wed, Apr 07, 2010 at 07:55:20PM +0200, Takashi Iwai wrote: > > At Wed, 7 Apr 2010 18:16:03 +0200, > > Daniel Mack wrote: > > > > > > On Wed, Apr 07, 2010 at 11:55:19AM -0400, Alan Stern wrote: > > > > On Wed, 7 Apr 2010, Greg KH wrote: > > > > > > > > > Alan, any objection to just using usb_buffer_alloc() for every driver? > > > > > Or is that too much overhead? > > > > > > > > I don't know what the overhead is. But usb_buffer_alloc() requires the > > > > caller to keep track of the buffer's DMA address, so it's not a simple > > > > plug-in replacement. In addition, the consistent memory that > > > > usb_buffer_alloc() provides is a scarce resource on some platforms. > > > > > > > > Writing new functions is the way to go. > > > > > > Ok, I'll write some dummies for usb_malloc() and usb_zalloc() which > > > will just call kmalloc() with GFP_DMA32 for now. > > > > Can't we provide only zalloc() variant? Zero'ing doesn't cost much, > > and the buffer allocation shouldn't be called too often. > > > > > And while at it, > > > usb_alloc_buffer() will be renamed to usb_alloc_consistent(). > > > > Most of recent functions are named with "coherent". > > I agree to both points, will do so unless anyone has a harsh opinion > about that. > > Another thing: I guess we don't need a corresponding free() function > that just calls kfree(), right? Or should we introduce it now to be > flexible for future extensions? Well, I would implement the corresponding free. It could be simply a macro calling kfree(), but it's saner to provide it for API uniformity, IMO. thanks, Takashi -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
