[PATCH v2 0/3] mm: Coccinelle-driven cleanups across memory management code

[PATCH v2 0/3] mm: Coccinelle-driven cleanups across memory management code

[Sahil Chandna]

This patch series contains three minor cleanups identified by
Coccinelle scripts under scripts/coccinelle/misc/:

  * Replace manual ternary expression with the min() macro in pagewalk.c
    and change return expression for clarity.
  * Use the %pe printk format specifier for PTR_ERR() reporting
    in vmscan.c and zswap.c
Found using:
  make coccicheck MODE=report M=mm/

changes in v2:
- Patch 1/3: update return value as per review comments.
- patch 2/3 and 3/3: Add Acked-by and Reviewed-by tags.

link to v1: https://lore.kernel.org/all/cover.1763227530.git.chandna.sahil@gmail.com/

Sahil Chandna (3):
  mm: pagewalk: simplify hugepage boundary calculation using min()
  mm/vmscan: use %pe to print error pointers
  mm/zswap: use %pe to print error pointers

 mm/pagewalk.c | 3 +--
 mm/vmscan.c   | 4 ++--
 mm/zswap.c    | 4 ++--
 3 files changed, 5 insertions(+), 6 deletions(-)

-- 
2.50.1

[PATCH v2 1/3] mm: pagewalk: simplify hugepage boundary calculation using min()

[Sahil Chandna]

Use the kernel-provided min() macro to compute the minimum value instead
of an explicit ternary expression. This improves readability and matches
common kernel style. Also change the return hugepage boundary expression
by using bitmask for better clarity.

This was flagged by Coccinelle
(misc/minmax.cocci) as an opportunity to use min().

Found by: make coccicheck MODE=report M=mm/
No functional change intended.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Suggested-by: David Laight <david.laight.linux@gmail.com>
Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
---
changes since v1:
- Updated boundary calculation of huge page range for better clarity.
- No Functional changes intended.
link to v1: https://lore.kernel.org/all/ff24b3c573b766b187b55a38497fbad0a319b9f8.1763227530.git.chandna.sahil@gmail.com/
---
 mm/pagewalk.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 9f91cf85a5be..1d38763a502a 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -312,8 +312,7 @@ static int walk_pgd_range(unsigned long addr, unsigned long end,
 static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
 				       unsigned long end)
 {
-	unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
-	return boundary < end ? boundary : end;
+	return min((addr | ~huge_page_mask(h)) + 1, end);
 }
 
 static int walk_hugetlb_range(unsigned long addr, unsigned long end,
-- 
2.50.1

Re: [PATCH v2 1/3] mm: pagewalk: simplify hugepage boundary calculation using min()

[David Hildenbrand (Red Hat)]

On 11/23/25 04:04, Sahil Chandna wrote:
> Use the kernel-provided min() macro to compute the minimum value instead
> of an explicit ternary expression. This improves readability and matches
> common kernel style. Also change the return hugepage boundary expression
> by using bitmask for better clarity.
> 
> This was flagged by Coccinelle
> (misc/minmax.cocci) as an opportunity to use min().
> 
> Found by: make coccicheck MODE=report M=mm/
> No functional change intended.
> 
> Suggested-by: Matthew Wilcox <willy@infradead.org>
> Suggested-by: David Laight <david.laight.linux@gmail.com>
> Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
> ---
> changes since v1:
> - Updated boundary calculation of huge page range for better clarity.
> - No Functional changes intended.
> link to v1: https://lore.kernel.org/all/ff24b3c573b766b187b55a38497fbad0a319b9f8.1763227530.git.chandna.sahil@gmail.com/
> ---
>   mm/pagewalk.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/mm/pagewalk.c b/mm/pagewalk.c
> index 9f91cf85a5be..1d38763a502a 100644
> --- a/mm/pagewalk.c
> +++ b/mm/pagewalk.c
> @@ -312,8 +312,7 @@ static int walk_pgd_range(unsigned long addr, unsigned long end,
>   static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
>   				       unsigned long end)
>   {
> -	unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
> -	return boundary < end ? boundary : end;
> +	return min((addr | ~huge_page_mask(h)) + 1, end);

I know Willy suggested that, but I wonder if we could simplify that to 
something a bit easier to digest:

	return min(ALIGN(addr, huge_page_size(h)), end);

At least I can make sense of that a bit faster.

(I don't think we're interested in micro-optimizations in this code here 
in particular :) )

-- 
Cheers

David

[PATCH v2 2/3] mm/vmscan: use %pe to print error pointers

[Sahil Chandna]

Use the %pe printk format specifier to report error pointers directly
instead of printing PTR_ERR() as a long value. This improves clarity,
produces more readable error messages.

This instance was flagged by the Coccinelle script
(misc/ptr_err_to_pe.cocci) as an opportunity to adopt %pe.

Found by: make coccicheck MODE=report M=mm/
No functional change intended

Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
---
 mm/vmscan.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index b2fc8b626d3d..7d5b41696cc3 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -7500,8 +7500,8 @@ void __meminit kswapd_run(int nid)
 		pgdat->kswapd = kthread_create_on_node(kswapd, pgdat, nid, "kswapd%d", nid);
 		if (IS_ERR(pgdat->kswapd)) {
 			/* failure at boot is fatal */
-			pr_err("Failed to start kswapd on node %d,ret=%ld\n",
-				   nid, PTR_ERR(pgdat->kswapd));
+			pr_err("Failed to start kswapd on node %d,ret=%pe\n",
+				   nid, pgdat->kswapd);
 			BUG_ON(system_state < SYSTEM_RUNNING);
 			pgdat->kswapd = NULL;
 		} else {
-- 
2.50.1

Re: [PATCH v2 2/3] mm/vmscan: use %pe to print error pointers

[David Hildenbrand (Red Hat)]

On 11/23/25 04:04, Sahil Chandna wrote:
> Use the %pe printk format specifier to report error pointers directly
> instead of printing PTR_ERR() as a long value. This improves clarity,
> produces more readable error messages.
> 
> This instance was flagged by the Coccinelle script
> (misc/ptr_err_to_pe.cocci) as an opportunity to adopt %pe.
> 
> Found by: make coccicheck MODE=report M=mm/
> No functional change intended
> 
> Reviewed-by: SeongJae Park <sj@kernel.org>
> Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
> ---

Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>

-- 
Cheers

David

[PATCH v2 3/3] mm/zswap: use %pe to print error pointers

[Sahil Chandna]

Use the %pe printk format specifier to report error pointers directly
instead of printing PTR_ERR() as a long value. This improves clarity,
produces more readable error messages.

This instance was flagged by the Coccinelle script
(misc/ptr_err_to_pe.cocci) as an opportunity to adopt %pe.

Found by: make coccicheck MODE=report M=mm/
No functional change intended.

Acked-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
---
 mm/zswap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/zswap.c b/mm/zswap.c
index c1af782e54ec..c35604db32ad 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -749,8 +749,8 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
 
 	acomp = crypto_alloc_acomp_node(pool->tfm_name, 0, 0, cpu_to_node(cpu));
 	if (IS_ERR(acomp)) {
-		pr_err("could not alloc crypto acomp %s : %ld\n",
-				pool->tfm_name, PTR_ERR(acomp));
+		pr_err("could not alloc crypto acomp %s : %pe\n",
+				pool->tfm_name, acomp);
 		ret = PTR_ERR(acomp);
 		goto fail;
 	}
-- 
2.50.1

Re: [PATCH v2 3/3] mm/zswap: use %pe to print error pointers

[David Hildenbrand (Red Hat)]

On 11/23/25 04:04, Sahil Chandna wrote:
> Use the %pe printk format specifier to report error pointers directly
> instead of printing PTR_ERR() as a long value. This improves clarity,
> produces more readable error messages.
> 
> This instance was flagged by the Coccinelle script
> (misc/ptr_err_to_pe.cocci) as an opportunity to adopt %pe.
> 
> Found by: make coccicheck MODE=report M=mm/
> No functional change intended.
> 
> Acked-by: Yosry Ahmed <yosry.ahmed@linux.dev>
> Acked-by: Nhat Pham <nphamcs@gmail.com>
> Reviewed-by: SeongJae Park <sj@kernel.org>
> Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
> ---

Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>

-- 
Cheers

David