On Mon, Jul 8, 2024 at 11:58 PM Yunsheng Lin <linyunsheng@xxxxxxxxxx> wrote: > > On 2024/7/8 22:30, Alexander Duyck wrote: > > On Mon, Jul 8, 2024 at 3:58 AM Yunsheng Lin <linyunsheng@xxxxxxxxxx> wrote: > >> > >> On 2024/7/8 1:12, Alexander Duyck wrote: > >> > >> ... > >> > >>> The issue is the dependency mess that has been created with patch 11 > >>> in the set. Again you are conflating patches which makes this really > >>> hard to debug or discuss as I make suggestions on one patch and you > >>> claim it breaks things that are really due to issues in another patch. > >>> So the issue is you included this header into include/linux/sched.h > >>> which is included in linux/mm_types.h. So what happens then is that > >>> you have to include page_frag_cache.h *before* you can include the > >>> bits from mm_types.h > >>> > >>> What might make more sense to solve this is to look at just moving the > >>> page_frag_cache into mm_types_task.h and then having it replace the > >>> page_frag struct there since mm_types.h will pull that in anyway. That > >>> way sched.h can avoid having to pull in page_frag_cache.h. > >> > >> It seems the above didn't work either, as asm-offsets.c does depend on > >> mm_types_task.h too. > >> > >> In file included from ./include/linux/mm.h:16, > >> from ./include/linux/page_frag_cache.h:10, > >> from ./include/linux/mm_types_task.h:11, > >> from ./include/linux/mm_types.h:5, > >> from ./include/linux/mmzone.h:22, > >> from ./include/linux/gfp.h:7, > >> from ./include/linux/slab.h:16, > >> from ./include/linux/resource_ext.h:11, > >> from ./include/linux/acpi.h:13, > >> from ./include/acpi/apei.h:9, > >> from ./include/acpi/ghes.h:5, > >> from ./include/linux/arm_sdei.h:8, > >> from arch/arm64/kernel/asm-offsets.c:10: > >> ./include/linux/mmap_lock.h: In function ‘mmap_assert_locked’: > >> ./include/linux/mmap_lock.h:65:23: error: invalid use of undefined type ‘const struct mm_struct’ > >> 65 | rwsem_assert_held(&mm->mmap_lock); > > > > Do not include page_frag_cache.h in mm_types_task.h. Just move the > > struct page_frag_cache there to replace struct page_frag. > > The above does seem a clever idea, but doesn't doing above also seem to > defeat some purpose of patch 1? Anyway, it seems workable for trying > to avoid adding a new header for a single struct. > > About the 'replace' part, as mentioned in [1], the 'struct page_frag' > is still needed as this patchset is large enough that replacing is only > done for sk_page_frag(), there are still other places using page_frag > that can be replaced by page_frag_cache in the following patchset. > > 1. https://lore.kernel.org/all/b200a609-2f30-ec37-39b6-f37ed8092f41@xxxxxxxxxx/ The point is you need to avoid pulling mm.h into sched.h. To do that you have to pull the data structure out and place it in a different header file. So maybe instead of creating yet another header file you can just place the structure in mm_types_task.h and once you have dealt with all of the other users you can finally drop the page_frag structure.
