[PATCH] uml: locking documentation
Some locking documentation and a cleanup. uml_exitcode is copied into a local
before sprintf sees it, in case sprintf does anything non-atomic with it.
The rest are comments about why certain globals don't need any kind of
locking.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/kernel/exitcode.c b/arch/um/kernel/exitcode.c
index d21ebad..8b7f2cd 100644
--- a/arch/um/kernel/exitcode.c
+++ b/arch/um/kernel/exitcode.c
@@ -16,9 +16,13 @@
static int read_proc_exitcode(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
- int len;
+ int len, val;
- len = sprintf(page, "%d\n", uml_exitcode);
+ /* Save uml_exitcode in a local so that we don't need to guarantee
+ * that sprintf accesses it atomically.
+ */
+ val = uml_exitcode;
+ len = sprintf(page, "%d\n", val);
len -= off;
if(len <= off+count) *eof = 1;
*start = page + off;