The patch titled
Subject: selftests: cgroup: return -errno from cg_read()/cg_write() on failure
has been added to the -mm tree. Its filename is
selftests-cgroup-return-errno-from-cg_read-cg_write-on-failure.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/selftests-cgroup-return-errno-from-cg_read-cg_write-on-failure.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/selftests-cgroup-return-errno-from-cg_read-cg_write-on-failure.patch
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------------------------------------------------------
From: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Subject: selftests: cgroup: return -errno from cg_read()/cg_write() on failure
Currently, cg_read()/cg_write() returns 0 on success and -1 on failure.
Modify them to return the -errno on failure.
Link: https://lkml.kernel.org/r/20220425190040.2475377-3-yosryahmed@xxxxxxxxxx
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Chen Wandun <chenwandun@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: "Michal Koutn" <mkoutny@xxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Cc: Vaibhav Jain <vaibhav@xxxxxxxxxxxxx>
Cc: Wei Xu <weixugc@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Zefan Li <lizefan.x@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/cgroup/cgroup_util.c | 44 +++++++----------
1 file changed, 19 insertions(+), 25 deletions(-)
--- a/tools/testing/selftests/cgroup/cgroup_util.c~selftests-cgroup-return-errno-from-cg_read-cg_write-on-failure
+++ a/tools/testing/selftests/cgroup/cgroup_util.c
@@ -19,6 +19,7 @@
#include "cgroup_util.h"
#include "../clone3/clone3_selftests.h"
+/* Returns read len on success, or -errno on failure. */
static ssize_t read_text(const char *path, char *buf, size_t max_len)
{
ssize_t len;
@@ -26,35 +27,29 @@ static ssize_t read_text(const char *pat
fd = open(path, O_RDONLY);
if (fd < 0)
- return fd;
+ return -errno;
len = read(fd, buf, max_len - 1);
- if (len < 0)
- goto out;
- buf[len] = 0;
-out:
+ if (len >= 0)
+ buf[len] = 0;
+
close(fd);
- return len;
+ return len < 0 ? -errno : len;
}
+/* Returns written len on success, or -errno on failure. */
static ssize_t write_text(const char *path, char *buf, ssize_t len)
{
int fd;
fd = open(path, O_WRONLY | O_APPEND);
if (fd < 0)
- return fd;
+ return -errno;
len = write(fd, buf, len);
- if (len < 0) {
- close(fd);
- return len;
- }
-
close(fd);
-
- return len;
+ return len < 0 ? -errno : len;
}
char *cg_name(const char *root, const char *name)
@@ -87,16 +82,16 @@ char *cg_control(const char *cgroup, con
return ret;
}
+/* Returns 0 on success, or -errno on failure. */
int cg_read(const char *cgroup, const char *control, char *buf, size_t len)
{
char path[PATH_MAX];
+ ssize_t ret;
snprintf(path, sizeof(path), "%s/%s", cgroup, control);
- if (read_text(path, buf, len) >= 0)
- return 0;
-
- return -1;
+ ret = read_text(path, buf, len);
+ return ret >= 0 ? 0 : ret;
}
int cg_read_strcmp(const char *cgroup, const char *control,
@@ -177,17 +172,15 @@ long cg_read_lc(const char *cgroup, cons
return cnt;
}
+/* Returns 0 on success, or -errno on failure. */
int cg_write(const char *cgroup, const char *control, char *buf)
{
char path[PATH_MAX];
- ssize_t len = strlen(buf);
+ ssize_t len = strlen(buf), ret;
snprintf(path, sizeof(path), "%s/%s", cgroup, control);
-
- if (write_text(path, buf, len) == len)
- return 0;
-
- return -1;
+ ret = write_text(path, buf, len);
+ return ret == len ? 0 : ret;
}
int cg_find_unified_root(char *root, size_t len)
@@ -557,7 +550,8 @@ ssize_t proc_read_text(int pid, bool thr
else
snprintf(path, sizeof(path), "/proc/%d/%s", pid, item);
- return read_text(path, buf, size);
+ size = read_text(path, buf, size);
+ return size < 0 ? -1 : size;
}
int proc_read_strstr(int pid, bool thread, const char *item, const char *needle)
_
Patches currently in -mm which might be from yosryahmed@xxxxxxxxxx are
selftests-cgroup-return-errno-from-cg_read-cg_write-on-failure.patch
selftests-cgroup-fix-alloc_anon_noexit-instantly-freeing-memory.patch
selftests-cgroup-add-a-selftest-for-memoryreclaim.patch
