On Wed, Oct 07, 2020 at 06:48:49AM +0100, Christoph Hellwig wrote: > > - .range_start = vma->vm_pgoff * PAGE_SIZE, > > + .range_start = (loff_t)vma->vm_pgoff * PAGE_SIZE, > > Given the may places where this issue shows up I think we really need > a vma_offset or similar helper for it. Much better than chasing missing > casts everywhere. Good point. I think these patches need to go in to fix the bugs in the various stable releases, but we should definitely have a helper for the future. Also, several of these patches are for non-VMA pgoff_t. vma_offset() is a bit weird for me -- vmas have all kinds of offsets. vma_file_offset() would work or vma_fpos(). I tend to prefer the shorter function name ;-) A quick grep shows we probably want a vmf_fpos() too: arch/powerpc/platforms/cell/spufs/file.c: unsigned long area, offset = vmf->pgoff << PAGE_SHIFT; arch/x86/entry/vdso/vma.c: sym_offset = (long)(vmf->pgoff << PAGE_SHIFT) + drivers/gpu/drm/gma500/framebuffer.c: address = vmf->address - (vmf->pgoff << PAGE_SHIFT); drivers/scsi/cxlflash/ocxl_hw.c: offset = vmf->pgoff << PAGE_SHIFT; I'm sure a lot of this will never run on a 32-bit kernel or with a 4GB file, but it's not good to have bad code around for people to copy from.
