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charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 3/16/26 15:38, Kevin Brodsky wrote: > On 16/03/2026 15:22, Ryan Roberts wrote: >>> static phys_addr_t __pgd_pgtable_alloc(struct mm_struct *mm, gfp_t gfp, >>> - enum pgtable_type pgtable_type) >>> + enum pgtable_level pgtable_level) >>> { >>> /* Page is zeroed by init_clear_pgtable() so don't duplicate effort. */ >>> struct ptdesc *ptdesc = pagetable_alloc(gfp & ~__GFP_ZERO, 0); >>> @@ -539,40 +539,42 @@ static phys_addr_t __pgd_pgtable_alloc(struct mm_struct *mm, gfp_t gfp, >>> >>> pa = page_to_phys(ptdesc_page(ptdesc)); >>> >>> - switch (pgtable_type) { >>> - case TABLE_PTE: >>> + switch (pgtable_level) { >>> + case PGTABLE_LEVEL_PTE: >>> BUG_ON(!pagetable_pte_ctor(mm, ptdesc)); >>> break; >>> - case TABLE_PMD: >>> + case PGTABLE_LEVEL_PMD: >>> BUG_ON(!pagetable_pmd_ctor(mm, ptdesc)); >>> break; >>> - case TABLE_PUD: >>> + case PGTABLE_LEVEL_PUD: >>> pagetable_pud_ctor(ptdesc); >>> break; >>> - case TABLE_P4D: >>> + case PGTABLE_LEVEL_P4D: >>> pagetable_p4d_ctor(ptdesc); >>> break; >>> + default: >>> + break; >> nit: I think we should either explicitly support pgd or explicitly bug/warn. Now >> that the enum has PGTABLE_LEVEL_PGD it looks legit to call __pgd_pgtable_alloc() >> to allocate one. But it will currently silently fail to call pagetable_pgd_ctor(). > > I hesitated there as well, eventually I concluded that we're dealing > with kernel page tables so we'll never allocate a PGD anyway... > >> Probably simplest just to call BUG() in the default path? > > ... but that's certainly fine by me :) If we could force it to be inline, we could turn it into a BUILD_BUG(). VM_WARN_ON() might be good enough I guess. -- Cheers, David