linux-kernel - Re: [PATCH v2] mm/vmalloc: Extend find_vmap_lowest_match

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Date:   Tue, 6 Sep 2022 16:25:04 +0000
From:   Song Liu <songliubraving@...com>
To:     Song Liu <song@...nel.org>
CC:     Linux-MM <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Uladzislau Rezki <urezki@...il.com>,
        Baoquan He <bhe@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2] mm/vmalloc: Extend find_vmap_lowest_match_check with
 extra arguments



> On Sep 5, 2022, at 11:05 PM, Song Liu <song@...nel.org> wrote:
> 
> find_vmap_lowest_match() is now able to handle different roots. With
> DEBUG_AUGMENT_LOWEST_MATCH_CHECK enabled as:
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index e68c0081e861..7552f1f8350e 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -713,7 +713,7 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
> /*** Global kva allocator ***/
> 
> -#define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0
> +#define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 1
> 
> compilation failed as:
> 
> mm/vmalloc.c: In function 'find_vmap_lowest_match_check':
> mm/vmalloc.c:1328:32: warning: passing argument 1 of 'find_vmap_lowest_match' makes pointer from integer without a cast [-Wint-conversion]
> 1328 |  va_1 = find_vmap_lowest_match(size, align, vstart, false);
>     |                                ^~~~
>     |                                |
>     |                                long unsigned int
> mm/vmalloc.c:1236:40: note: expected 'struct rb_root *' but argument is of type 'long unsigned int'
> 1236 | find_vmap_lowest_match(struct rb_root *root, unsigned long size,
>     |                        ~~~~~~~~~~~~~~~~^~~~
> mm/vmalloc.c:1328:9: error: too few arguments to function 'find_vmap_lowest_match'
> 1328 |  va_1 = find_vmap_lowest_match(size, align, vstart, false);
>     |         ^~~~~~~~~~~~~~~~~~~~~~
> mm/vmalloc.c:1236:1: note: declared here
> 1236 | find_vmap_lowest_match(struct rb_root *root, unsigned long size,
>     | ^~~~~~~~~~~~~~~~~~~~~~
> 
> Extend find_vmap_lowest_match_check() and find_vmap_lowest_linear_match()
> with extra arguments to fix this.
> 
> Fixes: f9863be49312 ("mm/vmalloc: extend __alloc_vmap_area() with extra arguments")
> Cc: Uladzislau Rezki (Sony) <urezki@...il.com>
> Cc: Baoquan He <bhe@...hat.com>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Signed-off-by: Song Liu <song@...nel.org>

Forgot to add the following from v1:

Reviewed-by: Baoquan He <bhe@...hat.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@...il.com>

> 
> ---
> Changes v1 => v2:
> 1. Update commit log to show the error with
>   DEBUG_AUGMENT_LOWEST_MATCH_CHECK. (Uladzislau Rezki, Baoquan He)
> ---
> mm/vmalloc.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index dd6cdb201195..088b421601c4 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1300,12 +1300,12 @@ find_vmap_lowest_match(struct rb_root *root, unsigned long size,
> #include <linux/random.h>
> 
> static struct vmap_area *
> -find_vmap_lowest_linear_match(unsigned long size,
> +find_vmap_lowest_linear_match(struct list_head *head, unsigned long size,
> 	unsigned long align, unsigned long vstart)
> {
> 	struct vmap_area *va;
> 
> -	list_for_each_entry(va, &free_vmap_area_list, list) {
> +	list_for_each_entry(va, head, list) {
> 		if (!is_within_this_va(va, size, align, vstart))
> 			continue;
> 
> @@ -1316,7 +1316,8 @@ find_vmap_lowest_linear_match(unsigned long size,
> }
> 
> static void
> -find_vmap_lowest_match_check(unsigned long size, unsigned long align)
> +find_vmap_lowest_match_check(struct rb_root *root, struct list_head *head,
> +			     unsigned long size, unsigned long align)
> {
> 	struct vmap_area *va_1, *va_2;
> 	unsigned long vstart;
> @@ -1325,8 +1326,8 @@ find_vmap_lowest_match_check(unsigned long size, unsigned long align)
> 	get_random_bytes(&rnd, sizeof(rnd));
> 	vstart = VMALLOC_START + rnd;
> 
> -	va_1 = find_vmap_lowest_match(size, align, vstart, false);
> -	va_2 = find_vmap_lowest_linear_match(size, align, vstart);
> +	va_1 = find_vmap_lowest_match(root, size, align, vstart, false);
> +	va_2 = find_vmap_lowest_linear_match(head, size, align, vstart);
> 
> 	if (va_1 != va_2)
> 		pr_emerg("not lowest: t: 0x%p, l: 0x%p, v: 0x%lx\n",
> @@ -1513,7 +1514,7 @@ __alloc_vmap_area(struct rb_root *root, struct list_head *head,
> 		return vend;
> 
> #if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
> -	find_vmap_lowest_match_check(size, align);
> +	find_vmap_lowest_match_check(root, head, size, align);
> #endif
> 
> 	return nva_start_addr;
> -- 
> 2.30.2
>