Messages in this thread | | | Date | Thu, 24 Mar 2011 08:25:21 +0000 | From | Russell King - ARM Linux <> | Subject | Re: Hit BUG_ON in dma-mapping.c:425 (RFC) |
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On Thu, Mar 24, 2011 at 04:18:13PM +0800, Nicolas Ferre wrote: > diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c > --- a/drivers/spi/atmel_spi.c > +++ b/drivers/spi/atmel_spi.c > @@ -647,6 +647,22 @@ static void atmel_spi_next_message(struct spi_master *master) > atmel_spi_next_xfer(master, msg); > } > > +static void *adjust_buffer_location(struct device *dev, void *buf) > +{ > + if (likely(buf < high_memory)) { > + return buf; > + } else { > + struct page *pg; > + > + pg = vmalloc_to_page(buf); > + if (pg == 0) { > + dev_err(dev, "failed to vmalloc_to_page\n"); > + return NULL; > + } > + return page_address(pg) + ((size_t)buf & ~PAGE_MASK); > + } > +} > +
This really doesn't fix the problem. If the page is read or written via the vmalloc mapping, you'll have stale data.
DMA to vmalloc areas is dodgy at best.
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