In usbfs mmap, usb_alloc_coherent is used to allocate memory.
This Memory is then remapped to user space memory using remap_pfn_range.
remap_pfn_range needs phy address of memory, for which virt_to_phy API
is used. This API works only if memory is allocated using kmalloc. But
usb_alloc_coherent can allocate memory in vmalloc range and this causes
wrong remap of user memory.
Check if address returned by usb_alloc_coherent failed in vmalloc range
and if yes, use remap_vmalloc_range API, else use remap_pfn_range to remap
address to user space.
Signed-off-by: Nagarjuna Kristam <nkristam@xxxxxxxxxx>
---
drivers/usb/core/devio.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index a945ad7..20999de 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -250,7 +250,12 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
usbm->vma_use_count = 1;
INIT_LIST_HEAD(&usbm->memlist);
- if (remap_pfn_range(vma, vma->vm_start,
+ if (is_vmalloc_addr(usbm->mem)) {
+ if (remap_vmalloc_range(vma, usbm->mem, 0) < 0) {
+ dec_usb_memory_use_count(usbm, &usbm->vma_use_count);
+ return -EAGAIN;
+ }
+ } else if (remap_pfn_range(vma, vma->vm_start,
virt_to_phys(usbm->mem) >> PAGE_SHIFT,
size, vma->vm_page_prot) < 0) {
dec_usb_memory_use_count(usbm, &usbm->vma_use_count);
--
2.7.4
