> -----Original Message----- > From: Gabbasov, Andrew > Sent: Monday, June 15, 2015 9:59 AM > To: [email protected] > Subject: [PATCH] spi: Fix per-page mapping of unaligned vmalloc-ed buffer > > spi_map_buf() processes mapping of vmalloc-ed buffers in a special way, making > mapping of every page separately. However, if the buffer is not aligned to page > boundary (e.g. sub-array in a vmalloc-ed array), it fills the scatter table with > page-size unaligned pieces, that cross page boundaries. This is incorrect and > can, for example, cause memory corruption and various crashes when working > with ubifs on spi-nor chips. > > Fix this by using proper scatter table size and intra-page buffer lengths, so that > the whole buffer splits into separate scatter table entries on page boundaries. > > Signed-off-by: Andrew Gabbasov <[email protected]> > --- > drivers/spi/spi.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 50910d8..14016dc 100644 > --- a/drivers/spi/spi.c > +++ b/drivers/spi/spi.c > @@ -477,7 +477,9 @@ static int spi_map_buf(struct spi_master *master, struct > device *dev, { > const bool vmalloced_buf = is_vmalloc_addr(buf); > const int desc_len = vmalloced_buf ? PAGE_SIZE : master- > >max_dma_len; > - const int sgs = DIV_ROUND_UP(len, desc_len); > + const int sgs = DIV_ROUND_UP(vmalloced_buf ? > + len + offset_in_page(buf) : len, > + desc_len); > struct page *vm_page; > void *sg_buf; > size_t min; > @@ -488,9 +490,10 @@ static int spi_map_buf(struct spi_master *master, > struct device *dev, > return ret; > > for (i = 0; i < sgs; i++) { > - min = min_t(size_t, len, desc_len); > > if (vmalloced_buf) { > + min = min_t(size_t, > + len, desc_len - offset_in_page(buf)); > vm_page = vmalloc_to_page(buf); > if (!vm_page) { > sg_free_table(sgt); > @@ -499,6 +502,7 @@ static int spi_map_buf(struct spi_master *master, struct > device *dev, > sg_set_page(&sgt->sgl[i], vm_page, > min, offset_in_page(buf)); > } else { > + min = min_t(size_t, len, desc_len); > sg_buf = buf; > sg_set_buf(&sgt->sgl[i], sg_buf, min); > } > -- > 2.1.0
Any opinion on this fix? Thanks. Best regards, Andrew -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
