From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
Since MPOL_F_NUMA_BALANCING was added some time ago, lets also recognise
it as a valid tmpfs mount option.
As an extension to the exiting format:
mpol=<mode>[=<flag>][:nodelist]
Multiple flags are added in a list separated by vertical bars, such as:
mpol=<mode>[=<flag>[|<flag>]...][:nodelist]
For example:
$ mount none -t tmpfs mnt -o mpol=bind=balancing:2,0
$ mount | grep mpol
none on ... type tmpfs (rw,relatime,mpol=bind=balancing:0,2)
Or:
$ mount none mnt -t tmpfs -o "mpol=bind=balancing|static:1,0"
$ mount | grep mpol
none on ... type tmpfs (rw,relatime,mpol=bind=balancing|static:0-1)
I am not sure to be honest if this is useful for tmpfs, but is just an
asymmetry I noticed while doing stuff in this area.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 55 +++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 43 insertions(+), 12 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 77488878d8ca..c69bf5438731 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -3162,6 +3162,47 @@ static const char * const policy_flags[] = {
};
#ifdef CONFIG_TMPFS
+static int mpol_lookup_flag(char *str)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(policy_flags); i++) {
+ if (policy_flags[i] && !strcmp(str, policy_flags[i]))
+ return BIT(i + __ffs(MPOL_MODE_FLAGS));
+ }
+
+ return -1;
+}
+
+static bool mpol_parse_flags(char *str, int *mode, unsigned short *flags)
+{
+ char buf[128], *opt;
+ int flag;
+
+ /* Make a local copy since caller wants the original untouched. */
+ if (WARN_ON_ONCE(strscpy(buf, str, sizeof(buf)) < 0))
+ return false;
+
+ str = buf;
+ for (;;) {
+ opt = strsep(&str, "|");
+
+ if (!opt)
+ break;
+ else if (*opt == '\0')
+ continue;
+
+ flag = mpol_lookup_flag(opt);
+ if (flag < 0)
+ return false;
+ *flags |= flag;
+ }
+
+ *mode |= *flags;
+
+ return sanitize_mpol_flags(mode, flags) == 0;
+}
+
/**
* mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option.
* @str: string containing mempolicy to parse
@@ -3247,18 +3288,8 @@ int mpol_parse_str(char *str, struct mempolicy **mpol)
}
mode_flags = 0;
- if (flags) {
- /*
- * Currently, we only support two mutually exclusive
- * mode flags.
- */
- if (!strcmp(flags, "static"))
- mode_flags |= MPOL_F_STATIC_NODES;
- else if (!strcmp(flags, "relative"))
- mode_flags |= MPOL_F_RELATIVE_NODES;
- else
- goto out;
- }
+ if (flags && !mpol_parse_flags(flags, &mode, &mode_flags))
+ goto out;
new = mpol_new(mode, mode_flags, &nodes);
if (IS_ERR(new))
--
2.44.0
