Messages in this thread Patch in this message | | | Subject | Re: Hit BUG_ON in dma-mapping.c:425 (RFC) | From | Artem Bityutskiy <> | Date | Thu, 24 Mar 2011 10:36:18 +0200 |
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On Thu, 2011-03-24 at 08:25 +0000, Russell King - ARM Linux wrote: > 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.
This topics pops up often. So what is the right fix? And sorry for my ignorance.
-- Best Regards, Artem Bityutskiy (Артём Битюцкий)
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