On Tue, Apr 29, 2025 at 08:55:47PM +0000, Pranjal Shrivastava wrote: > On Tue, Apr 29, 2025 at 01:39:09PM -0700, Nicolin Chen wrote: > > On Tue, Apr 29, 2025 at 08:34:56PM +0000, Pranjal Shrivastava wrote: > > > On Tue, Apr 29, 2025 at 08:24:33PM +0000, Pranjal Shrivastava wrote: > > > > On Fri, Apr 25, 2025 at 10:58:08PM -0700, Nicolin Chen wrote: > > > > > + struct iommufd_mmap *immap; > > > > > + int rc; > > > > > + > > > > > + if (WARN_ON_ONCE(!immap_id)) > > > > > + return -EINVAL; > > > > > + if (base & ~PAGE_MASK) > > > > > + return -EINVAL; > > > > > + if (!size || size & ~PAGE_MASK) > > > > > + return -EINVAL; > > > > > + > > > > > + immap = kzalloc(sizeof(*immap), GFP_KERNEL); > > > > > + if (!immap) > > > > > + return -ENOMEM; > > > > > + immap->pfn_start = base >> PAGE_SHIFT; > > > > > + immap->pfn_end = immap->pfn_start + (size >> PAGE_SHIFT) - 1; > > > > > + > > > > > + rc = mtree_alloc_range(&ictx->mt_mmap, immap_id, immap, > > > > > sizeof(immap), > > > > > > > > I believe this should be sizeof(*immap) ? > > > > > > Ugh, Sorry, shouldn't this be size >> PAGE_SHIFT (num_indices to alloc) ? > > > > mtree_load() returns a "struct iommufd_map *" pointer. > > I'm not talking about mtree_load. I meant mtree_alloc_range takes in a > "size" parameter, which is being passed as sizeof(imap) in this patch. > IIUC, the mtree_alloc_range, via mas_empty_area, gets a range that is > sufficient for the given "size". > > Now in this case, "size" would be the no. of pfns which are mmap-able. > By passing sizeof(immap), we're simply reserving sizeof(ptr) i.e. 8 pfns > for a 64-bit machine. Whereas we really, just want to reserve a range > for size >> PAGE_SHIFT pfns.
But we are not storing pfns but the immap pointer.. Nicolin
