mm: introduce pure page table freeing function

The pages used for ptdescs are currently freed back to the allocator in a
single location.  They will shortly be freed from a second location.

Create a simple helper that just frees them back to the allocator.

Link: https://lkml.kernel.org/r/20251022082635.2462433-6-baolu.lu@linux.intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasant Hegde <vasant.hegde@amd.com>
Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yi Lai <yi1.lai@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8f46048875a729163405cc3a1654d5da1e2617ee..88c0a0fae43af058f63252a9be1b9b35f8d67c03 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3046,6 +3046,13 @@ static inline struct ptdesc *pagetable_alloc_noprof(gfp_t gfp, unsigned int orde
 }
 #define pagetable_alloc(...)   alloc_hooks(pagetable_alloc_noprof(__VA_ARGS__))
 
+static inline void __pagetable_free(struct ptdesc *pt)
+{
+       struct page *page = ptdesc_page(pt);
+
+       __free_pages(page, compound_order(page));
+}
+
 /**
  * pagetable_free - Free pagetables
  * @pt:        The page table descriptor
@@ -3055,12 +3062,10 @@ static inline struct ptdesc *pagetable_alloc_noprof(gfp_t gfp, unsigned int orde
  */
 static inline void pagetable_free(struct ptdesc *pt)
 {
-       struct page *page = ptdesc_page(pt);
-
        if (ptdesc_test_kernel(pt))
                ptdesc_clear_kernel(pt);
 
-       __free_pages(page, compound_order(page));
+       __pagetable_free(pt);
 }
 
 #if defined(CONFIG_SPLIT_PTE_PTLOCKS)