Re: [PATCH 2/3] tools/testing: add PROCMAP_QUERY helper functions in mm self tests

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Mon, Mar 17, 2025 at 09:15:04PM +0000, Lorenzo Stoakes wrote:
> The PROCMAP_QUERY ioctl() is very useful - it allows for binary access to
> /proc/$pid/[s]maps data and thus convenient lookup of data contained there.
>
> This patch exposes this for convenient use by mm self tests so the state of
> VMAs can easily be queried.
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Quick fix on this:

----8<----
From 02d674de3736e3726a97a27625d4598c3d49d08a Mon Sep 17 00:00:00 2001
From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Date: Tue, 18 Mar 2025 15:16:29 +0000
Subject: [PATCH] correctly return errno

---
 tools/testing/selftests/mm/vm_util.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
index 891ce17453cd..1357e2d6a7b6 100644
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -440,7 +440,7 @@ int open_procmap(pid_t pid, struct procmap_fd *procmap_out)
 	procmap_out->query.size = sizeof(procmap_out->query);
 	procmap_out->fd = open(path, O_RDONLY);
 	if (procmap_out < 0)
-		ret = errno;
+		ret = -errno;

 	return ret;
 }
@@ -451,7 +451,7 @@ int query_procmap(struct procmap_fd *procmap)
 	int ret = 0;

 	if (ioctl(procmap->fd, PROCMAP_QUERY, &procmap->query) == -1)
-		ret = errno;
+		ret = -errno;

 	return ret;
 }
--
2.48.1