From 02683ffdf655b4ae15245376ba6fea6d9e5829a6 Mon Sep 17 00:00:00 2001 From: "Andrew G. Harvey" Date: Wed, 24 Sep 2008 01:10:02 +0200 Subject: UIO: Fix mapping of logical and virtual memory mmap() doesn't work as expected for UIO_MEM_LOGICAL or UIO_MEM_VIRTUAL mappings. The offset into the memory needs to be added, otherwise uio_vma_fault always returns the first page only. Note that for UIO userspace calls mmap() with offset = N * getpagesize() to access mapping N. This must be compensated when calculating the offset. A comment was added to explain this since it is not obvious. Signed-off-by: Andrew G. Harvey Signed-off-by: Hans J. Koch Signed-off-by: Greg Kroah-Hartman --- drivers/uio/uio.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c index 557e73ef588..5dccf057a7d 100644 --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -490,15 +490,23 @@ static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { struct uio_device *idev = vma->vm_private_data; struct page *page; + unsigned long offset; int mi = uio_find_mem_index(vma); if (mi < 0) return VM_FAULT_SIGBUS; + /* + * We need to subtract mi because userspace uses offset = N*PAGE_SIZE + * to use mem[N]. + */ + offset = (vmf->pgoff - mi) << PAGE_SHIFT; + if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL) - page = virt_to_page(idev->info->mem[mi].addr); + page = virt_to_page(idev->info->mem[mi].addr + offset); else - page = vmalloc_to_page((void*)idev->info->mem[mi].addr); + page = vmalloc_to_page((void *)idev->info->mem[mi].addr + + offset); get_page(page); vmf->page = page; return 0; -- cgit v1.2.3-18-g5258