[v6,2/5] mm/sparse-vmemmap: refactor core of vmemmap_populate_basepages() to helper

Commit Message

Joao Martins Feb. 23, 2022, 7:48 p.m. UTC

In preparation for describing a memmap with compound pages, move the
actual pte population logic into a separate function
vmemmap_populate_address() and have vmemmap_populate_basepages() walk
through all base pages it needs to populate.

While doing that, change the helper to use a pte_t* as return value,
rather than an hardcoded errno of 0 or -ENOMEM.

Signed-off-by: Joao Martins <[e-mail]>
---
 mm/sparse-vmemmap.c | 46 ++++++++++++++++++++++++++++-----------------
 1 file changed, 29 insertions(+), 17 deletions(-)

Comments

Muchun Song Feb. 24, 2022, 3:10 a.m. UTC | #1

On Thu, Feb 24, 2022 at 3:48 AM Joao Martins <[e-mail]> wrote:
>
> In preparation for describing a memmap with compound pages, move the
> actual pte population logic into a separate function
> vmemmap_populate_address() and have vmemmap_populate_basepages() walk
> through all base pages it needs to populate.
>
> While doing that, change the helper to use a pte_t* as return value,
> rather than an hardcoded errno of 0 or -ENOMEM.
>
> Signed-off-by: Joao Martins <[e-mail]>

Reviewed-by: Muchun Song <[e-mail]>

Thanks.

Joao Martins Feb. 24, 2022, 10:39 a.m. UTC | #2

On 2/24/22 03:10, Muchun Song wrote:
> On Thu, Feb 24, 2022 at 3:48 AM Joao Martins <[e-mail]> wrote:
>>
>> In preparation for describing a memmap with compound pages, move the
>> actual pte population logic into a separate function
>> vmemmap_populate_address() and have vmemmap_populate_basepages() walk
>> through all base pages it needs to populate.
>>
>> While doing that, change the helper to use a pte_t* as return value,
>> rather than an hardcoded errno of 0 or -ENOMEM.
>>
>> Signed-off-by: Joao Martins <[e-mail]>
> 
> Reviewed-by: Muchun Song <[e-mail]>

I've added this one too, thanks for the thorough review!

Patch

diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index c506f77cff23..44cb77523003 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -608,33 +608,45 @@  pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
 	return pgd;
 }
 
-int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
-					 int node, struct vmem_altmap *altmap)
+static pte_t * __meminit vmemmap_populate_address(unsigned long addr, int node,
+					      struct vmem_altmap *altmap)
 {
-	unsigned long addr = start;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 
+	pgd = vmemmap_pgd_populate(addr, node);
+	if (!pgd)
+		return NULL;
+	p4d = vmemmap_p4d_populate(pgd, addr, node);
+	if (!p4d)
+		return NULL;
+	pud = vmemmap_pud_populate(p4d, addr, node);
+	if (!pud)
+		return NULL;
+	pmd = vmemmap_pmd_populate(pud, addr, node);
+	if (!pmd)
+		return NULL;
+	pte = vmemmap_pte_populate(pmd, addr, node, altmap);
+	if (!pte)
+		return NULL;
+	vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
+
+	return pte;
+}
+
+int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
+					 int node, struct vmem_altmap *altmap)
+{
+	unsigned long addr = start;
+	pte_t *pte;
+
 	for (; addr < end; addr += PAGE_SIZE) {
-		pgd = vmemmap_pgd_populate(addr, node);
-		if (!pgd)
-			return -ENOMEM;
-		p4d = vmemmap_p4d_populate(pgd, addr, node);
-		if (!p4d)
-			return -ENOMEM;
-		pud = vmemmap_pud_populate(p4d, addr, node);
-		if (!pud)
-			return -ENOMEM;
-		pmd = vmemmap_pmd_populate(pud, addr, node);
-		if (!pmd)
-			return -ENOMEM;
-		pte = vmemmap_pte_populate(pmd, addr, node, altmap);
+		pte = vmemmap_populate_address(addr, node, altmap);
 		if (!pte)
 			return -ENOMEM;
-		vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
 	}
 
 	return 0;