[PATCH v3 4/7] mm/vmalloc: explicitly identify vm_map_ram area when shown in /proc/vmcoreinfo

From: Baoquan He <bhe@redhat.com>
To: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org, urezki@gmail.com,
	lstoakes@gmail.com, stephen.s.brennan@oracle.com,
	willy@infradead.org, akpm@linux-foundation.org,
	hch@infradead.org, Baoquan He <bhe@redhat.com>
Subject: [PATCH v3 4/7] mm/vmalloc: explicitly identify vm_map_ram area when shown in /proc/vmcoreinfo
Date: Fri, 13 Jan 2023 11:19:18 +0800	[thread overview]
Message-ID: <20230113031921.64716-5-bhe@redhat.com> (raw)
In-Reply-To: <20230113031921.64716-1-bhe@redhat.com>

Now, by marking VMAP_RAM in vmap_area->flags for vm_map_ram, we can
clearly differentiate it with other vmalloc areas. So identify
vm_map_area area by checking VMAP_RAM of vmap_area->flags when shown
in /proc/vmcoreinfo.

Meanwhile, the code comment above vm_map_ram area checking in s_show()
is not needed any more, remove it here.

Signed-off-by: Baoquan He <bhe@redhat.com>
---
 mm/vmalloc.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 13875bc41e27..4a10b3b692fa 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4225,11 +4225,7 @@ static int s_show(struct seq_file *m, void *p)
 
 	va = list_entry(p, struct vmap_area, list);
 
-	/*
-	 * s_show can encounter race with remove_vm_area, !vm on behalf
-	 * of vmap area is being tear down or vm_map_ram allocation.
-	 */
-	if (!va->vm) {
+	if (!va->vm && (va->flags & VMAP_RAM)) {
 		seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n",
 			(void *)va->va_start, (void *)va->va_end,
 			va->va_end - va->va_start);
-- 
2.34.1

