diff options
| author | Jeff Dike <jdike@addtoit.com> | 2006-09-29 01:58:50 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-29 09:18:04 -0700 |
| commit | 730760e90a173ef81f89beed2f1dad2fab310f68 (patch) | |
| tree | e60039deb19683fac30e58277450c657ecd33e07 /arch/um | |
| parent | b10aeeef554eb1ff80e10111829f6e7484877811 (diff) | |
[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/um')
| -rw-r--r-- | arch/um/drivers/null.c | 1 | ||||
| -rw-r--r-- | arch/um/drivers/random.c | 4 | ||||
| -rw-r--r-- | arch/um/drivers/stderr_console.c | 2 | ||||
| -rw-r--r-- | arch/um/drivers/stdio_console.c | 1 | ||||
| -rw-r--r-- | arch/um/kernel/exitcode.c | 8 |
5 files changed, 14 insertions, 2 deletions
diff --git a/arch/um/drivers/null.c b/arch/um/drivers/null.c index 3683ed44315d..9016c68beee8 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 ae9909415b9c..73b2bdd6d2d3 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 6d2cf32a9e8f..911539293871 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 5e44adb07051..e4bfcfe8550b 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 d21ebad666b4..8b7f2cdedf94 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; |