On Thu, Oct 18, 2012 at 10:59:56AM +0100, Alan Cox wrote: > > > + skb_headlen(skb), > > > + DMA_TO_DEVICE); > > > + desc[frag].addr_lo = dma_addr & 0xFFFFFFFF; > > > + desc[frag].addr_hi = dma_addr >> 32; > > > > Maybe use macros defined in kernel.h instead: > > > > desc[frag].addr_lo = lower_32_bits(dma_addr); > > desc[frag].addr_hi = upper_32_bits(dma_addr); > > > > A few more instances below. > > This is actually important because >> 32 of a 32bit value is undefined in > C. The compiler is free to do what it likes with this. While the results > are usually sane some architectures do generate the equivalent of > > x >> (n % wordsize); > > Alan Thanks for the comments both. I'll send an updated patch this evening. The intention is to eventually store this value as a dma_addr_t anyway, but some more work needs to be done to copy the address correctly to the desc ring. Cheers, Mark _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
