linux-kernel - [PATCH RFC 04/14] mm/huge_memory: move more common code into insert

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Message-ID: <20250617154345.2494405-5-david@redhat.com>
Date: Tue, 17 Jun 2025 17:43:35 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-fsdevel@...r.kernel.org,
	linux-mm@...ck.org,
	nvdimm@...ts.linux.dev,
	David Hildenbrand <david@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Juergen Gross <jgross@...e.com>,
	Stefano Stabellini <sstabellini@...nel.org>,
	Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
	Dan Williams <dan.j.williams@...el.com>,
	Alistair Popple <apopple@...dia.com>,
	Matthew Wilcox <willy@...radead.org>,
	Jan Kara <jack@...e.cz>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Christian Brauner <brauner@...nel.org>,
	Zi Yan <ziy@...dia.com>,
	Baolin Wang <baolin.wang@...ux.alibaba.com>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>,
	Nico Pache <npache@...hat.com>,
	Ryan Roberts <ryan.roberts@....com>,
	Dev Jain <dev.jain@....com>,
	Barry Song <baohua@...nel.org>,
	Vlastimil Babka <vbabka@...e.cz>,
	Mike Rapoport <rppt@...nel.org>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Michal Hocko <mhocko@...e.com>,
	Jann Horn <jannh@...gle.com>,
	Pedro Falcato <pfalcato@...e.de>
Subject: [PATCH RFC 04/14] mm/huge_memory: move more common code into insert_pmd()

Let's clean it all further up.

Signed-off-by: David Hildenbrand <david@...hat.com>
---
 mm/huge_memory.c | 72 ++++++++++++++++--------------------------------
 1 file changed, 24 insertions(+), 48 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e52360df87d15..a85e0cd455109 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1379,15 +1379,25 @@ struct folio_or_pfn {
 	bool is_folio;
 };
 
-static int insert_pmd(struct vm_area_struct *vma, unsigned long addr,
+static vm_fault_t insert_pmd(struct vm_area_struct *vma, unsigned long addr,
 		pmd_t *pmd, struct folio_or_pfn fop, pgprot_t prot,
-		bool write, pgtable_t pgtable)
+		bool write)
 {
 	struct mm_struct *mm = vma->vm_mm;
+	pgtable_t pgtable = NULL;
+	spinlock_t *ptl;
 	pmd_t entry;
 
-	lockdep_assert_held(pmd_lockptr(mm, pmd));
+	if (addr < vma->vm_start || addr >= vma->vm_end)
+		return VM_FAULT_SIGBUS;
 
+	if (arch_needs_pgtable_deposit()) {
+		pgtable = pte_alloc_one(vma->vm_mm);
+		if (!pgtable)
+			return VM_FAULT_OOM;
+	}
+
+	ptl = pmd_lock(mm, pmd);
 	if (!pmd_none(*pmd)) {
 		const unsigned long pfn = fop.is_folio ? folio_pfn(fop.folio) :
 					  fop.pfn;
@@ -1395,15 +1405,14 @@ static int insert_pmd(struct vm_area_struct *vma, unsigned long addr,
 		if (write && pmd_present(*pmd)) {
 			if (pmd_pfn(*pmd) != pfn) {
 				WARN_ON_ONCE(!is_huge_zero_pmd(*pmd));
-				return -EEXIST;
+				goto out_unlock;
 			}
 			entry = pmd_mkyoung(*pmd);
 			entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
 			if (pmdp_set_access_flags(vma, addr, pmd, entry, 1))
 				update_mmu_cache_pmd(vma, addr, pmd);
 		}
-
-		return -EEXIST;
+		goto out_unlock;
 	}
 
 	if (fop.is_folio) {
@@ -1424,11 +1433,17 @@ static int insert_pmd(struct vm_area_struct *vma, unsigned long addr,
 	if (pgtable) {
 		pgtable_trans_huge_deposit(mm, pmd, pgtable);
 		mm_inc_nr_ptes(mm);
+		pgtable = NULL;
 	}
 
 	set_pmd_at(mm, addr, pmd, entry);
 	update_mmu_cache_pmd(vma, addr, pmd);
-	return 0;
+
+out_unlock:
+	spin_unlock(ptl);
+	if (pgtable)
+		pte_free(mm, pgtable);
+	return VM_FAULT_NOPAGE;
 }
 
 /**
@@ -1450,9 +1465,6 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, unsigned long pfn,
 	struct folio_or_pfn fop = {
 		.pfn = pfn,
 	};
-	pgtable_t pgtable = NULL;
-	spinlock_t *ptl;
-	int error;
 
 	/*
 	 * If we had pmd_special, we could avoid all these restrictions,
@@ -1464,25 +1476,9 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, unsigned long pfn,
 						(VM_PFNMAP|VM_MIXEDMAP));
 	BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
 
-	if (addr < vma->vm_start || addr >= vma->vm_end)
-		return VM_FAULT_SIGBUS;
-
-	if (arch_needs_pgtable_deposit()) {
-		pgtable = pte_alloc_one(vma->vm_mm);
-		if (!pgtable)
-			return VM_FAULT_OOM;
-	}
-
 	pfnmap_setup_cachemode_pfn(pfn, &pgprot);
 
-	ptl = pmd_lock(vma->vm_mm, vmf->pmd);
-	error = insert_pmd(vma, addr, vmf->pmd, fop, pgprot, write,
-			   pgtable);
-	spin_unlock(ptl);
-	if (error && pgtable)
-		pte_free(vma->vm_mm, pgtable);
-
-	return VM_FAULT_NOPAGE;
+	return insert_pmd(vma, addr, vmf->pmd, fop, pgprot, write);
 }
 EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd);
 
@@ -1491,35 +1487,15 @@ vm_fault_t vmf_insert_folio_pmd(struct vm_fault *vmf, struct folio *folio,
 {
 	struct vm_area_struct *vma = vmf->vma;
 	unsigned long addr = vmf->address & PMD_MASK;
-	struct mm_struct *mm = vma->vm_mm;
 	struct folio_or_pfn fop = {
 		.folio = folio,
 		.is_folio = true,
 	};
-	spinlock_t *ptl;
-	pgtable_t pgtable = NULL;
-	int error;
-
-	if (addr < vma->vm_start || addr >= vma->vm_end)
-		return VM_FAULT_SIGBUS;
 
 	if (WARN_ON_ONCE(folio_order(folio) != PMD_ORDER))
 		return VM_FAULT_SIGBUS;
 
-	if (arch_needs_pgtable_deposit()) {
-		pgtable = pte_alloc_one(vma->vm_mm);
-		if (!pgtable)
-			return VM_FAULT_OOM;
-	}
-
-	ptl = pmd_lock(mm, vmf->pmd);
-	error = insert_pmd(vma, addr, vmf->pmd, fop, vma->vm_page_prot,
-			   write, pgtable);
-	spin_unlock(ptl);
-	if (error && pgtable)
-		pte_free(mm, pgtable);
-
-	return VM_FAULT_NOPAGE;
+	return insert_pmd(vma, addr, vmf->pmd, fop, vma->vm_page_prot, write);
 }
 EXPORT_SYMBOL_GPL(vmf_insert_folio_pmd);
 
-- 
2.49.0