On Tue, Aug 4, 2026 at 4:42 PM Boris Brezillon <[email protected]> wrote: > Okay, I thought I'd ask to be sure, because of all the implementations > of pfn_mkwrite listed here [1], only drm_gem_shmem_helper.c and > kernel/events/core.c do that.
Also the vmwgfx one in patch 3; and for the !DAX case ext4 and XFS too (e.g. xfs_filemap_pfn_mkwrite gets to iomap_page_mkwrite, not to filemap_fault). > The rest have their "generic" fault > handler (by generic I mean a fault handler helper that covers all the > order/WRITE_FLAG combinations) called from pfn_mkwrite(), and return a > non-zero vm_fault_t. I see; I think you can do that, it is handled at https://elixir.bootlin.com/linux/v7.2-rc5/source/mm/memory.c#L2681 and indeed it returns VM_FAULT_NOPAGE. But it's more or work for no real reason. Your .pfn_mkwrite is a single line of code and it is clearer IMO if you can see that try_insert_pfn() is calling the same helper as .pfn_mkwrite(). Paolo
