From 948927ee9e4f35f287e61a79c9f0e85ca2202c7d Mon Sep 17 00:00:00 2001
From: David Rientjes <rientjes@google.com>
Date: Tue, 12 Nov 2013 15:07:28 -0800
Subject: mm, mempolicy: make mpol_to_str robust and always succeed
mpol_to_str() should not fail. Currently, it either fails because the
string buffer is too small or because a string hasn't been defined for a
mempolicy mode.
If a new mempolicy mode is introduced and no string is defined for it,
just warn and return "unknown".
If the buffer is too small, just truncate the string and return, the
same behavior as snprintf().
This also fixes a bug where there was no NULL-byte termination when doing
*p++ = '=' and *p++ ':' and maxlen has been reached.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Chen Gang <gang.chen@asianux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/mempolicy.c | 52 ++++++++++++++++------------------------------------
1 file changed, 16 insertions(+), 36 deletions(-)
(limited to 'mm/mempolicy.c')
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 71cb253368c..260b8213a87 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2914,62 +2914,45 @@ out:
* @maxlen: length of @buffer
* @pol: pointer to mempolicy to be formatted
*
- * Convert a mempolicy into a string.
- * Returns the number of characters in buffer (if positive)
- * or an error (negative)
+ * Convert @pol into a string. If @buffer is too short, truncate the string.
+ * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
+ * longest flag, "relative", and to display at least a few node ids.
*/
-int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
+void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
{
char *p = buffer;
- int l;
- nodemask_t nodes;
- unsigned short mode;
- unsigned short flags = pol ? pol->flags : 0;
-
- /*
- * Sanity check: room for longest mode, flag and some nodes
- */
- VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
+ nodemask_t nodes = NODE_MASK_NONE;
+ unsigned short mode = MPOL_DEFAULT;
+ unsigned short flags = 0;
- if (!pol || pol == &default_policy)
- mode = MPOL_DEFAULT;
- else
+ if (pol && pol != &default_policy) {
mode = pol->mode;
+ flags = pol->flags;
+ }
switch (mode) {
case MPOL_DEFAULT:
- nodes_clear(nodes);
break;
-
case MPOL_PREFERRED:
- nodes_clear(nodes);
if (flags & MPOL_F_LOCAL)
mode = MPOL_LOCAL;
else
node_set(pol->v.preferred_node, nodes);
break;
-
case MPOL_BIND:
- /* Fall through */
case MPOL_INTERLEAVE:
nodes = pol->v.nodes;
break;
-
default:
- return -EINVAL;
+ WARN_ON_ONCE(1);
+ snprintf(p, maxlen, "unknown");
+ return;
}
- l = strlen(policy_modes[mode]);
- if (buffer + maxlen < p + l + 1)
- return -ENOSPC;
-
- strcpy(p, policy_modes[mode]);
- p += l;
+ p += snprintf(p, maxlen, policy_modes[mode]);
if (flags & MPOL_MODE_FLAGS) {
- if (buffer + maxlen < p + 2)
- return -ENOSPC;
- *p++ = '=';
+ p += snprintf(p, buffer + maxlen - p, "=");
/*
* Currently, the only defined flags are mutually exclusive
@@ -2981,10 +2964,7 @@ int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
}
if (!nodes_empty(nodes)) {
- if (buffer + maxlen < p + 2)
- return -ENOSPC;
- *p++ = ':';
+ p += snprintf(p, buffer + maxlen - p, ":");
p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);
}
- return p - buffer;
}
--
cgit v1.2.3-70-g09d2
From b76ac7e734608d706bf225be062a7a46d165dda6 Mon Sep 17 00:00:00 2001
From: Jianguo Wu <wujianguo@huawei.com>
Date: Tue, 12 Nov 2013 15:07:39 -0800
Subject: mm/mempolicy: use NUMA_NO_NODE
Use more appropriate NUMA_NO_NODE instead of -1
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/mempolicy.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
(limited to 'mm/mempolicy.c')
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 260b8213a87..4cc19f6ab6c 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1125,7 +1125,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
tmp = *from;
while (!nodes_empty(tmp)) {
int s,d;
- int source = -1;
+ int source = NUMA_NO_NODE;
int dest = 0;
for_each_node_mask(s, tmp) {
@@ -1160,7 +1160,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
if (!node_isset(dest, tmp))
break;
}
- if (source == -1)
+ if (source == NUMA_NO_NODE)
break;
node_clear(source, tmp);
@@ -1835,7 +1835,7 @@ static unsigned offset_il_node(struct mempolicy *pol,
unsigned nnodes = nodes_weight(pol->v.nodes);
unsigned target;
int c;
- int nid = -1;
+ int nid = NUMA_NO_NODE;
if (!nnodes)
return numa_node_id();
@@ -1872,11 +1872,11 @@ static inline unsigned interleave_nid(struct mempolicy *pol,
/*
* Return the bit number of a random bit set in the nodemask.
- * (returns -1 if nodemask is empty)
+ * (returns NUMA_NO_NODE if nodemask is empty)
*/
int node_random(const nodemask_t *maskp)
{
- int w, bit = -1;
+ int w, bit = NUMA_NO_NODE;
w = nodes_weight(*maskp);
if (w)
--
cgit v1.2.3-70-g09d2