misc: mic: scif bug fix for vmalloc_to_page crash
v4.2-rc1 enabled huge page support for ioremap(..).
Calling vmalloc_to_page after v4.2-rc1 results in the
crash shown below on the host upon booting X100 coprocessors:
BUG: unable to handle kernel paging request at ffffc47c00000000
IP: [<ffffffff811a2c0c>] vmalloc_to_page+0x6c/0xb0
This patch fixes this crash by obtaining the fake struct page
pointer which is required to be passed into dma_map_sg(..)
by calling pfn_to_page(..) instead of vmalloc_to_page(..).
Link: https://lkml.org/lkml/2015/7/18/110
Reviewed-by: Nikhil Rao <nikhil.rao@intel.com>
Suggested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/mic/scif/scif_nodeqp.c b/drivers/misc/mic/scif/scif_nodeqp.c
index 41e3bdb..6dfdae3 100644
--- a/drivers/misc/mic/scif/scif_nodeqp.c
+++ b/drivers/misc/mic/scif/scif_nodeqp.c
@@ -357,7 +357,7 @@
}
static struct scatterlist *
-scif_p2p_setsg(void __iomem *va, int page_size, int page_cnt)
+scif_p2p_setsg(phys_addr_t pa, int page_size, int page_cnt)
{
struct scatterlist *sg;
struct page *page;
@@ -368,16 +368,11 @@
return NULL;
sg_init_table(sg, page_cnt);
for (i = 0; i < page_cnt; i++) {
- page = vmalloc_to_page((void __force *)va);
- if (!page)
- goto p2p_sg_err;
+ page = pfn_to_page(pa >> PAGE_SHIFT);
sg_set_page(&sg[i], page, page_size, 0);
- va += page_size;
+ pa += page_size;
}
return sg;
-p2p_sg_err:
- kfree(sg);
- return NULL;
}
/* Init p2p mappings required to access peerdev from scifdev */
@@ -395,14 +390,14 @@
p2p = kzalloc(sizeof(*p2p), GFP_KERNEL);
if (!p2p)
return NULL;
- p2p->ppi_sg[SCIF_PPI_MMIO] = scif_p2p_setsg(psdev->mmio->va,
+ p2p->ppi_sg[SCIF_PPI_MMIO] = scif_p2p_setsg(psdev->mmio->pa,
PAGE_SIZE, num_mmio_pages);
if (!p2p->ppi_sg[SCIF_PPI_MMIO])
goto free_p2p;
p2p->sg_nentries[SCIF_PPI_MMIO] = num_mmio_pages;
sg_page_shift = get_order(min(psdev->aper->len, (u64)(1 << 30)));
num_aper_chunks = num_aper_pages >> (sg_page_shift - PAGE_SHIFT);
- p2p->ppi_sg[SCIF_PPI_APER] = scif_p2p_setsg(psdev->aper->va,
+ p2p->ppi_sg[SCIF_PPI_APER] = scif_p2p_setsg(psdev->aper->pa,
1 << sg_page_shift,
num_aper_chunks);
p2p->sg_nentries[SCIF_PPI_APER] = num_aper_chunks;