The quilt patch titled
Subject: mm: document pXd_leaf() API
has been removed from the -mm tree. Its filename was
mm-document-pxd_leaf-api.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm: document pXd_leaf() API
Date: Mon, 18 Mar 2024 16:04:04 -0400
There's one small section already, but since we're going to remove
pXd_huge(), that comment may start to obsolete.
Rewrite that section with more information, hopefully with that the API is
crystal clear on what it implies.
Link: https://lkml.kernel.org/r/20240318200404.448346-15-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Andreas Larsson <andreas@xxxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Bjorn Andersson <andersson@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Fabio Estevam <festevam@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: Mark Salter <msalter@xxxxxxxxxx>
Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Naoya Horiguchi <nao.horiguchi@xxxxxxxxx>
Cc: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pgtable.h | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)
--- a/include/linux/pgtable.h~mm-document-pxd_leaf-api
+++ a/include/linux/pgtable.h
@@ -1768,11 +1768,25 @@ typedef unsigned int pgtbl_mod_mask;
#endif
/*
- * p?d_leaf() - true if this entry is a final mapping to a physical address.
- * This differs from p?d_huge() by the fact that they are always available (if
- * the architecture supports large pages at the appropriate level) even
- * if CONFIG_HUGETLB_PAGE is not defined.
- * Only meaningful when called on a valid entry.
+ * pXd_leaf() is the API to check whether a pgtable entry is a huge page
+ * mapping. It should work globally across all archs, without any
+ * dependency on CONFIG_* options. For architectures that do not support
+ * huge mappings on specific levels, below fallbacks will be used.
+ *
+ * A leaf pgtable entry should always imply the following:
+ *
+ * - It is a "present" entry. IOW, before using this API, please check it
+ * with pXd_present() first. NOTE: it may not always mean the "present
+ * bit" is set. For example, PROT_NONE entries are always "present".
+ *
+ * - It should _never_ be a swap entry of any type. Above "present" check
+ * should have guarded this, but let's be crystal clear on this.
+ *
+ * - It should contain a huge PFN, which points to a huge page larger than
+ * PAGE_SIZE of the platform. The PFN format isn't important here.
+ *
+ * - It should cover all kinds of huge mappings (e.g., pXd_trans_huge(),
+ * pXd_devmap(), or hugetlb mappings).
*/
#ifndef pgd_leaf
#define pgd_leaf(x) false
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-userfaultfd-reset-ptes-when-close-for-wr-protected-ones.patch
mm-hugetlb-assert-hugetlb_lock-in-__hugetlb_cgroup_commit_charge.patch
mm-page_table_check-support-userfault-wr-protect-entries.patch
