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authorJeff Dike <jdike@addtoit.com>2006-09-29 01:58:50 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-29 09:18:04 -0700
commit730760e90a173ef81f89beed2f1dad2fab310f68 (patch)
treee60039deb19683fac30e58277450c657ecd33e07 /arch
parentb10aeeef554eb1ff80e10111829f6e7484877811 (diff)
downloadlinaro-lsk-730760e90a173ef81f89beed2f1dad2fab310f68.tar.gz
[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>
Diffstat (limited to 'arch')
-rw-r--r--arch/um/drivers/null.c1
-rw-r--r--arch/um/drivers/random.c4
-rw-r--r--arch/um/drivers/stderr_console.c2
-rw-r--r--arch/um/drivers/stdio_console.c1
-rw-r--r--arch/um/kernel/exitcode.c8
5 files changed, 14 insertions, 2 deletions
diff --git a/arch/um/drivers/null.c b/arch/um/drivers/null.c
index 3683ed44315..9016c68beee 100644
--- a/arch/um/drivers/null.c
+++ b/arch/um/drivers/null.c
@@ -8,6 +8,7 @@
#include "chan_user.h"
#include "os.h"
+/* This address is used only as a unique identifer */
static int null_chan;
static void *null_init(char *str, int device, const struct chan_opts *opts)
diff --git a/arch/um/drivers/random.c b/arch/um/drivers/random.c
index ae9909415b9..73b2bdd6d2d 100644
--- a/arch/um/drivers/random.c
+++ b/arch/um/drivers/random.c
@@ -20,6 +20,10 @@
#define RNG_MISCDEV_MINOR 183 /* official */
+/* Changed at init time, in the non-modular case, and at module load
+ * time, in the module case. Presumably, the module subsystem
+ * protects against a module being loaded twice at the same time.
+ */
static int random_fd = -1;
static int rng_dev_open (struct inode *inode, struct file *filp)
diff --git a/arch/um/drivers/stderr_console.c b/arch/um/drivers/stderr_console.c
index 6d2cf32a9e8..91153929387 100644
--- a/arch/um/drivers/stderr_console.c
+++ b/arch/um/drivers/stderr_console.c
@@ -9,6 +9,8 @@
/*
* Don't register by default -- as this registeres very early in the
* boot process it becomes the default console.
+ *
+ * Initialized at init time.
*/
static int use_stderr_console = 0;
diff --git a/arch/um/drivers/stdio_console.c b/arch/um/drivers/stdio_console.c
index 5e44adb0705..e4bfcfe8550 100644
--- a/arch/um/drivers/stdio_console.c
+++ b/arch/um/drivers/stdio_console.c
@@ -108,6 +108,7 @@ static int con_open(struct tty_struct *tty, struct file *filp)
return line_open(vts, tty);
}
+/* Set in an initcall, checked in an exitcall */
static int con_init_done = 0;
static const struct tty_operations console_ops = {
diff --git a/arch/um/kernel/exitcode.c b/arch/um/kernel/exitcode.c
index d21ebad666b..8b7f2cdedf9 100644
--- a/arch/um/kernel/exitcode.c
+++ b/arch/um/kernel/exitcode.c
@@ -16,9 +16,13 @@ int uml_exitcode = 0;
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;