diff options
| author | Lee Schermerhorn <lee.schermerhorn@hp.com> | 2008-04-28 02:13:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-28 08:58:24 -0700 |
| commit | 2291990ab36b4b2d8a81b1f92e7a046e51632a60 (patch) | |
| tree | b5b6b8ca9c92bc3c84cd7e7aefb5010d3793db4d /mm | |
| parent | fc36b8d3d819047eb4d23ca079fb4d3af20ff076 (diff) | |
mempolicy: clean-up mpol-to-str() mempolicy formatting
mpol-to-str() formats memory policies into printable strings. Currently this
is only used to display "numa_maps". A subsequent patch will use
mpol_to_str() for formatting tmpfs [shmem] mpol mount options, allowing us to
remove essentially duplicate code in mm/shmem.c. This patch cleans up
mpol_to_str() generally and in preparation for that patch.
1) show_numa_maps() is not checking the return code from mpol_to_str().
There's not a lot we can do in this context if mpol_to_str() did return the
error [insufficient space in buffer]. Proposed "solution": just check,
under DEBUG_VM, that callers are providing sufficient buffer space for the
policy, flags, and a few nodes. This way, we'll get some display.
show_numa_maps() is providing a 50-byte buffer, so it won't trip this
check. 50-bytes should be sufficient unless one has a large number of
nodes in a very sparse nodemask.
2) The display of the new mode flags ["static" & "relative"] was set up to
display multiple flags, separated by a "bar" '|'. However, this support is
incomplete--e.g., need_bar was never incremented; and currently, these two
flags are mutually exclusive. So remove the "bar" support, for now, and
only display one flag.
3) Use snprint() to format flags, so as not to overflow the buffer. Not
that it's ever happed, AFAIK.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/mempolicy.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 143b019e9834..3c8ee31572ec 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1965,6 +1965,11 @@ static inline int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) 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); + if (!pol || pol == &default_policy) mode = MPOL_DEFAULT; else @@ -1991,7 +1996,6 @@ static inline int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) default: BUG(); - return -EFAULT; } l = strlen(policy_types[mode]); @@ -2002,16 +2006,17 @@ static inline int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) p += l; if (flags & MPOL_MODE_FLAGS) { - int need_bar = 0; - if (buffer + maxlen < p + 2) return -ENOSPC; *p++ = '='; + /* + * Currently, the only defined flags are mutually exclusive + */ if (flags & MPOL_F_STATIC_NODES) - p += sprintf(p, "%sstatic", need_bar++ ? "|" : ""); - if (flags & MPOL_F_RELATIVE_NODES) - p += sprintf(p, "%srelative", need_bar++ ? "|" : ""); + p += snprintf(p, buffer + maxlen - p, "static"); + else if (flags & MPOL_F_RELATIVE_NODES) + p += snprintf(p, buffer + maxlen - p, "relative"); } if (!nodes_empty(nodes)) { |