[PATCH 6/9] UML - console locking commentary and code cleanup
From: Jeff Dike
Date: Fri Jan 05 2007 - 13:49:34 EST
Remove the last vestiges of devfs from console registration. Change
the name of the function, plus remove a couple of unused fields from
the line_driver structure.
struct lines is no longer needed, all traces of it are gone.
The only way that I can see to mark a structure as being almost-const
is to individually const the fields. This is the case for the
line_driver structure, which has only one modifiable field - a
list_head in a sub-structure.
Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>
--
arch/um/drivers/line.c | 7 +++----
arch/um/drivers/ssl.c | 16 +++++++---------
arch/um/drivers/stdio_console.c | 17 +++++++----------
arch/um/include/line.h | 36 ++++++++++++++----------------------
4 files changed, 31 insertions(+), 45 deletions(-)
Index: linux-2.6.18-mm/arch/um/drivers/line.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/drivers/line.c 2007-01-01 13:34:20.000000000 -0500
+++ linux-2.6.18-mm/arch/um/drivers/line.c 2007-01-02 13:27:16.000000000 -0500
@@ -707,10 +707,9 @@ int line_remove(struct line *lines, unsi
return err;
}
-struct tty_driver *line_register_devfs(struct lines *set,
- struct line_driver *line_driver,
- const struct tty_operations *ops,
- struct line *lines, int nlines)
+struct tty_driver *register_lines(struct line_driver *line_driver,
+ const struct tty_operations *ops,
+ struct line *lines, int nlines)
{
int i;
struct tty_driver *driver = alloc_tty_driver(nlines);
Index: linux-2.6.18-mm/arch/um/drivers/ssl.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/drivers/ssl.c 2007-01-02 12:25:18.000000000 -0500
+++ linux-2.6.18-mm/arch/um/drivers/ssl.c 2007-01-02 13:31:38.000000000 -0500
@@ -51,6 +51,8 @@ static int ssl_config(char *str, char **
static int ssl_get_config(char *dev, char *str, int size, char **error_out);
static int ssl_remove(int n, char **error_out);
+
+/* Const, except for .mc.list */
static struct line_driver driver = {
.name = "UML serial line",
.device_name = "ttyS",
@@ -62,8 +64,6 @@ static struct line_driver driver = {
.read_irq_name = "ssl",
.write_irq = SSL_WRITE_IRQ,
.write_irq_name = "ssl-write",
- .symlink_from = "serial",
- .symlink_to = "tts",
.mc = {
.list = LIST_HEAD_INIT(driver.mc.list),
.name = "ssl",
@@ -74,14 +74,12 @@ static struct line_driver driver = {
},
};
-/* The array is initialized by line_init, which is an initcall. The
- * individual elements are protected by individual semaphores.
+/* The array is initialized by line_init, at initcall time. The
+ * elements are locked individually as needed.
*/
static struct line serial_lines[NR_PORTS] =
{ [0 ... NR_PORTS - 1] = LINE_INIT(CONFIG_SSL_CHAN, &driver) };
-static struct lines lines = LINES_INIT(NR_PORTS);
-
static int ssl_config(char *str, char **error_out)
{
return line_config(serial_lines, ARRAY_SIZE(serial_lines), str, &opts,
@@ -175,6 +173,7 @@ static int ssl_console_setup(struct cons
return console_open_chan(line, co);
}
+/* No locking for register_console call - relies on single-threaded initcalls */
static struct console ssl_cons = {
.name = "ttyS",
.write = ssl_console_write,
@@ -190,9 +189,8 @@ static int ssl_init(void)
printk(KERN_INFO "Initializing software serial port version %d\n",
ssl_version);
- ssl_driver = line_register_devfs(&lines, &driver, &ssl_ops,
- serial_lines,
- ARRAY_SIZE(serial_lines));
+ ssl_driver = register_lines(&driver, &ssl_ops, serial_lines,
+ ARRAY_SIZE(serial_lines));
lines_init(serial_lines, ARRAY_SIZE(serial_lines), &opts);
Index: linux-2.6.18-mm/arch/um/drivers/stdio_console.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/drivers/stdio_console.c 2007-01-01 13:30:24.000000000 -0500
+++ linux-2.6.18-mm/arch/um/drivers/stdio_console.c 2007-01-02 13:31:51.000000000 -0500
@@ -55,6 +55,8 @@ static int con_config(char *str, char **
static int con_get_config(char *dev, char *str, int size, char **error_out);
static int con_remove(int n, char **con_remove);
+
+/* Const, except for .mc.list */
static struct line_driver driver = {
.name = "UML console",
.device_name = "tty",
@@ -66,8 +68,6 @@ static struct line_driver driver = {
.read_irq_name = "console",
.write_irq = CONSOLE_WRITE_IRQ,
.write_irq_name = "console-write",
- .symlink_from = "ttys",
- .symlink_to = "vc",
.mc = {
.list = LIST_HEAD_INIT(driver.mc.list),
.name = "con",
@@ -78,10 +78,8 @@ static struct line_driver driver = {
},
};
-static struct lines console_lines = LINES_INIT(MAX_TTYS);
-
-/* The array is initialized by line_init, which is an initcall. The
- * individual elements are protected by individual semaphores.
+/* The array is initialized by line_init, at initcall time. The
+ * elements are locked individually as needed.
*/
static struct line vts[MAX_TTYS] = { LINE_INIT(CONFIG_CON_ZERO_CHAN, &driver),
[ 1 ... MAX_TTYS - 1 ] =
@@ -149,6 +147,7 @@ static int uml_console_setup(struct cons
return console_open_chan(line, co);
}
+/* No locking for register_console call - relies on single-threaded initcalls */
static struct console stdiocons = {
.name = "tty",
.write = uml_console_write,
@@ -156,16 +155,14 @@ static struct console stdiocons = {
.setup = uml_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
- .data = &vts,
};
int stdio_init(void)
{
char *new_title;
- console_driver = line_register_devfs(&console_lines, &driver,
- &console_ops, vts,
- ARRAY_SIZE(vts));
+ console_driver = register_lines(&driver, &console_ops, vts,
+ ARRAY_SIZE(vts));
if (console_driver == NULL)
return -1;
printk(KERN_INFO "Initialized stdio console driver\n");
Index: linux-2.6.18-mm/arch/um/include/line.h
===================================================================
--- linux-2.6.18-mm.orig/arch/um/include/line.h 2006-12-29 17:26:54.000000000 -0500
+++ linux-2.6.18-mm/arch/um/include/line.h 2007-01-02 13:29:54.000000000 -0500
@@ -15,19 +15,18 @@
#include "chan_user.h"
#include "mconsole_kern.h"
+/* There's only one modifiable field in this - .mc.list */
struct line_driver {
- char *name;
- char *device_name;
- short major;
- short minor_start;
- short type;
- short subtype;
- int read_irq;
- char *read_irq_name;
- int write_irq;
- char *write_irq_name;
- char *symlink_from;
- char *symlink_to;
+ const char *name;
+ const char *device_name;
+ const short major;
+ const short minor_start;
+ const short type;
+ const short subtype;
+ const int read_irq;
+ const char *read_irq_name;
+ const int write_irq;
+ const char *write_irq_name;
struct mc_device mc;
};
@@ -67,12 +66,6 @@ struct line {
.lock = SPIN_LOCK_UNLOCKED, \
.driver = d }
-struct lines {
- int num;
-};
-
-#define LINES_INIT(n) { .num = n }
-
extern void line_close(struct tty_struct *tty, struct file * filp);
extern int line_open(struct line *lines, struct tty_struct *tty);
extern int line_setup(struct line *lines, unsigned int sizeof_lines,
@@ -94,10 +87,9 @@ extern char *add_xterm_umid(char *base);
extern int line_setup_irq(int fd, int input, int output, struct line *line,
void *data);
extern void line_close_chan(struct line *line);
-extern struct tty_driver * line_register_devfs(struct lines *set,
- struct line_driver *line_driver,
- const struct tty_operations *driver,
- struct line *lines, int nlines);
+extern struct tty_driver *register_lines(struct line_driver *line_driver,
+ const struct tty_operations *driver,
+ struct line *lines, int nlines);
extern void lines_init(struct line *lines, int nlines, struct chan_opts *opts);
extern void close_lines(struct line *lines, int nlines);
-
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