mm: avoid unnecessary use of is_swap_pmd()

PMD 'non-swap' swap entries are currently used for PMD-level migration
entries and device private entries.

To add to the confusion in this terminology we use is_swap_pmd() in an
inconsistent way similar to how is_swap_pte() was being used - sometimes
adopting the convention that !pmd_none(), !pmd_present() implies PMD 'swap'
entry, sometimes not.

This patch handles the low-hanging fruit of cases where we can simply
substitute other predicates for is_swap_pmd().

No functional change intended.

Link: https://lkml.kernel.org/r/8a1704b36a009c18032d5bea4cb68e71448fbbe5.1762812360.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 12 insertions, 3 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8c35ea48a93e..1bedf7fa5e79 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1059,10 +1059,12 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 	bool present = false;
 	struct folio *folio;
 
+	if (pmd_none(*pmd))
+		return;
 	if (pmd_present(*pmd)) {
 		page = vm_normal_page_pmd(vma, addr, *pmd);
 		present = true;
-	} else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) {
+	} else if (unlikely(thp_migration_supported())) {
 		swp_entry_t entry = pmd_to_swp_entry(*pmd);
 
 		if (is_pfn_swap_entry(entry))
@@ -2000,6 +2002,9 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr,
 	if (vma->vm_flags & VM_SOFTDIRTY)
 		flags |= PM_SOFT_DIRTY;
 
+	if (pmd_none(pmd))
+		goto populate_pagemap;
+
 	if (pmd_present(pmd)) {
 		page = pmd_page(pmd);
 
@@ -2010,7 +2015,7 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr,
 			flags |= PM_UFFD_WP;
 		if (pm->show_pfn)
 			frame = pmd_pfn(pmd) + idx;
-	} else if (thp_migration_supported() && is_swap_pmd(pmd)) {
+	} else if (thp_migration_supported()) {
 		swp_entry_t entry = pmd_to_swp_entry(pmd);
 		unsigned long offset;
 
@@ -2037,6 +2042,7 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr,
 			flags |= PM_FILE;
 	}
 
+populate_pagemap:
 	for (; addr != end; addr += PAGE_SIZE, idx++) {
 		u64 cur_flags = flags;
 		pagemap_entry_t pme;
@@ -2399,6 +2405,9 @@ static unsigned long pagemap_thp_category(struct pagemap_scan_private *p,
 {
 	unsigned long categories = PAGE_IS_HUGE;
 
+	if (pmd_none(pmd))
+		return categories;
+
 	if (pmd_present(pmd)) {
 		struct page *page;
 
@@ -2416,7 +2425,7 @@ static unsigned long pagemap_thp_category(struct pagemap_scan_private *p,
 			categories |= PAGE_IS_PFNZERO;
 		if (pmd_soft_dirty(pmd))
 			categories |= PAGE_IS_SOFT_DIRTY;
-	} else if (is_swap_pmd(pmd)) {
+	} else {
 		swp_entry_t swp;
 
 		categories |= PAGE_IS_SWAPPED;