usb: core: config.c: usb_get_configuration() simplified
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From: Alan Stern on 17 Apr 2010 12:20 On Sat, 17 Apr 2010, Michal Nazarewicz wrote: > usb_gat_configuratio() used two pointers to point to the same > memory. Code simplified, by removing one of them. > > Signed-off-by: Michal Nazarewicz <mina86(a)mina86.com> > --- > drivers/usb/core/config.c | 10 ++++------ > 1 files changed, 4 insertions(+), 6 deletions(-) > > > On Sat, 17 Apr 2010, Michal Nazarewicz wrote: > >> usb_get_configuration() uses a temporary buffer allocated on heap > >> to read USB configuration descriptor. The buffer is just nine > >> bytes an so it is a waste to allocate it on heap where it can be > >> allocated on stack with the rest of local variables. This > >> simplifies the code and minimises memory usage. > > Alan Stern <stern(a)rowland.harvard.edu> writes: > > This is completely wrong. You are not allowed to do DMA to buffers on > > the stack; some architectures are not capable of handling it. > > That makes sense; I haven't considered this thinking that copying nine > bytes by CPU, rather then using DMA, is not a big issue. > > Still, the change proposed by attached commit does not suffer from DMA > issue and still simplify the code. Yes, this is fine. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |