[PATCH 0/2] mm/cma: ise for_each_clear_bitrange() where appropriate

[PATCH 0/2] mm/cma: ise for_each_clear_bitrange() where appropriate

[Yury Norov]

From: Yury Norov (NVIDIA) <yury.norov@gmail.com>

Hi Andrew,

Pleas pull a couple of simplifications for mm/cma.

Thanks,
Yury

Yury Norov (NVIDIA) (2):
  mm: cma: simplify cma_debug_show_areas()
  mm: cma: simplify cma_maxchunk_get()

 mm/cma.c       | 19 ++++---------------
 mm/cma_debug.c | 10 +---------
 2 files changed, 5 insertions(+), 24 deletions(-)

-- 
2.43.0

[PATCH 1/2] mm: cma: simplify cma_debug_show_areas()

[Yury Norov]

From: Yury Norov (NVIDIA) <yury.norov@gmail.com>

The function opencodes for_each_clear_bitrange(). Fix that and drop most
of housekeeping code.

Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
---
 mm/cma.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/mm/cma.c b/mm/cma.c
index 397567883a10..adc57bf7c68c 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -739,8 +739,7 @@ static int __init __cma_declare_contiguous_nid(phys_addr_t *basep,
 
 static void cma_debug_show_areas(struct cma *cma)
 {
-	unsigned long next_zero_bit, next_set_bit, nr_zero;
-	unsigned long start;
+	unsigned long start, end;
 	unsigned long nr_part;
 	unsigned long nbits;
 	int r;
@@ -751,22 +750,12 @@ static void cma_debug_show_areas(struct cma *cma)
 	for (r = 0; r < cma->nranges; r++) {
 		cmr = &cma->ranges[r];
 
-		start = 0;
 		nbits = cma_bitmap_maxno(cma, cmr);
 
 		pr_info("range %d: ", r);
-		for (;;) {
-			next_zero_bit = find_next_zero_bit(cmr->bitmap,
-							   nbits, start);
-			if (next_zero_bit >= nbits)
-				break;
-			next_set_bit = find_next_bit(cmr->bitmap, nbits,
-						     next_zero_bit);
-			nr_zero = next_set_bit - next_zero_bit;
-			nr_part = nr_zero << cma->order_per_bit;
-			pr_cont("%s%lu@%lu", start ? "+" : "", nr_part,
-				next_zero_bit);
-			start = next_zero_bit + nr_zero;
+		for_each_clear_bitrange(start, end, cmr->bitmap, nbits) {
+			nr_part = (end - start) << cma->order_per_bit;
+			pr_cont("%s%lu@%lu", start ? "+" : "", nr_part, start);
 		}
 		pr_info("\n");
 	}
-- 
2.43.0

[PATCH 2/2] mm: cma: simplify cma_maxchunk_get()

[Yury Norov]

From: Yury Norov (NVIDIA) <yury.norov@gmail.com>

The function opencodes for_each_clear_bitrange(). Fix that and drop most
of housekeeping code.

Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
---
 mm/cma_debug.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/mm/cma_debug.c b/mm/cma_debug.c
index fdf899532ca0..8c7d7f8e8fbd 100644
--- a/mm/cma_debug.c
+++ b/mm/cma_debug.c
@@ -56,16 +56,8 @@ static int cma_maxchunk_get(void *data, u64 *val)
 	for (r = 0; r < cma->nranges; r++) {
 		cmr = &cma->ranges[r];
 		bitmap_maxno = cma_bitmap_maxno(cma, cmr);
-		end = 0;
-		for (;;) {
-			start = find_next_zero_bit(cmr->bitmap,
-						   bitmap_maxno, end);
-			if (start >= bitmap_maxno)
-				break;
-			end = find_next_bit(cmr->bitmap, bitmap_maxno,
-					    start);
+		for_each_clear_bitrange(start, end, cmr->bitmap, bitmap_maxno)
 			maxchunk = max(end - start, maxchunk);
-		}
 	}
 	spin_unlock_irq(&cma->lock);
 	*val = (u64)maxchunk << cma->order_per_bit;
-- 
2.43.0

Re: [PATCH 2/2] mm: cma: simplify cma_maxchunk_get()

[David Hildenbrand]

On 19.07.25 22:54, Yury Norov wrote:
> From: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> 
> The function opencodes for_each_clear_bitrange(). Fix that and drop most
> of housekeeping code.

Not sure if talking about a "fix" it the right word here.

Acked-by: David Hildenbrand <david@redhat.com>

> 
> Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> ---
>   mm/cma_debug.c | 10 +---------
>   1 file changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/mm/cma_debug.c b/mm/cma_debug.c
> index fdf899532ca0..8c7d7f8e8fbd 100644
> --- a/mm/cma_debug.c
> +++ b/mm/cma_debug.c
> @@ -56,16 +56,8 @@ static int cma_maxchunk_get(void *data, u64 *val)
>   	for (r = 0; r < cma->nranges; r++) {
>   		cmr = &cma->ranges[r];
>   		bitmap_maxno = cma_bitmap_maxno(cma, cmr);
> -		end = 0;
> -		for (;;) {
> -			start = find_next_zero_bit(cmr->bitmap,
> -						   bitmap_maxno, end);
> -			if (start >= bitmap_maxno)
> -				break;
> -			end = find_next_bit(cmr->bitmap, bitmap_maxno,
> -					    start);
> +		for_each_clear_bitrange(start, end, cmr->bitmap, bitmap_maxno)
>   			maxchunk = max(end - start, maxchunk);
> -		}
>   	}
>   	spin_unlock_irq(&cma->lock);
>   	*val = (u64)maxchunk << cma->order_per_bit;


-- 
Cheers,

David / dhildenb

Re: [PATCH 1/2] mm: cma: simplify cma_debug_show_areas()

[David Hildenbrand]

On 19.07.25 22:53, Yury Norov wrote:
> From: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> 
> The function opencodes for_each_clear_bitrange(). Fix that and drop most
> of housekeeping code.

Same comment regarding "fix" as for patch #2

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb