提交 84f48d4f 编写于 作者: J Jeff Dike 提交者: Linus Torvalds

[PATCH] uml: mconsole locking

Locking fixes.  Locking was totally lacking for the mconsole_devices, which
got a spin lock, and the unplugged pages data, which got a mutex.

The locking of the mconsole console output code was confused.  Now, the
console_lock (renamed to client_lock) protects the clients list.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 d471c0fc
......@@ -337,13 +337,15 @@ void mconsole_stop(struct mc_request *req)
mconsole_reply(req, "", 0, 0);
}
/* This list is populated by __initcall routines. */
static DEFINE_SPINLOCK(mc_devices_lock);
static LIST_HEAD(mconsole_devices);
void mconsole_register_dev(struct mc_device *new)
{
spin_lock(&mc_devices_lock);
BUG_ON(!list_empty(&new->list));
list_add(&new->list, &mconsole_devices);
spin_unlock(&mc_devices_lock);
}
static struct mc_device *mconsole_find_dev(char *name)
......@@ -367,6 +369,7 @@ struct unplugged_pages {
void *pages[UNPLUGGED_PER_PAGE];
};
static DECLARE_MUTEX(plug_mem_mutex);
static unsigned long long unplugged_pages_count = 0;
static struct list_head unplugged_pages = LIST_HEAD_INIT(unplugged_pages);
static int unplug_index = UNPLUGGED_PER_PAGE;
......@@ -402,6 +405,7 @@ static int mem_config(char *str, char **error_out)
diff /= PAGE_SIZE;
down(&plug_mem_mutex);
for(i = 0; i < diff; i++){
struct unplugged_pages *unplugged;
void *addr;
......@@ -447,7 +451,7 @@ static int mem_config(char *str, char **error_out)
printk("Failed to release memory - "
"errno = %d\n", err);
*error_out = "Failed to release memory";
goto out;
goto out_unlock;
}
unplugged->pages[unplug_index++] = addr;
}
......@@ -457,6 +461,8 @@ static int mem_config(char *str, char **error_out)
}
err = 0;
out_unlock:
up(&plug_mem_mutex);
out:
return err;
}
......@@ -487,6 +493,7 @@ static int mem_remove(int n, char **error_out)
}
static struct mc_device mem_mc = {
.list = LIST_HEAD_INIT(mem_mc.list),
.name = "mem",
.config = mem_config,
.get_config = mem_get_config,
......@@ -629,7 +636,7 @@ struct mconsole_output {
struct mc_request *req;
};
static DEFINE_SPINLOCK(console_lock);
static DEFINE_SPINLOCK(client_lock);
static LIST_HEAD(clients);
static char console_buf[MCONSOLE_MAX_DATA];
static int console_index = 0;
......@@ -684,16 +691,18 @@ static void with_console(struct mc_request *req, void (*proc)(void *),
unsigned long flags;
entry.req = req;
spin_lock_irqsave(&client_lock, flags);
list_add(&entry.list, &clients);
spin_lock_irqsave(&console_lock, flags);
spin_unlock_irqrestore(&client_lock, flags);
(*proc)(arg);
mconsole_reply_len(req, console_buf, console_index, 0, 0);
console_index = 0;
spin_unlock_irqrestore(&console_lock, flags);
spin_lock_irqsave(&client_lock, flags);
list_del(&entry.list);
spin_unlock_irqrestore(&client_lock, flags);
}
#ifdef CONFIG_MAGIC_SYSRQ
......
......@@ -690,6 +690,7 @@ static int net_remove(int n, char **error_out)
}
static struct mc_device net_mc = {
.list = LIST_HEAD_INIT(net_mc.list),
.name = "eth",
.config = net_config,
.get_config = NULL,
......
......@@ -64,6 +64,7 @@ static struct line_driver driver = {
.symlink_from = "serial",
.symlink_to = "tts",
.mc = {
.list = LIST_HEAD_INIT(driver.mc.list),
.name = "ssl",
.config = ssl_config,
.get_config = ssl_get_config,
......
......@@ -828,6 +828,7 @@ static int ubd_remove(int n, char **error_out)
* ubd-specific locks.
*/
static struct mc_device ubd_mc = {
.list = LIST_HEAD_INIT(ubd_mc.list),
.name = "ubd",
.config = ubd_config,
.get_config = ubd_get_config,
......
......@@ -12,6 +12,7 @@ extern int gdb_config(char *str, char **error_out);
extern int gdb_remove(int n, char **error_out);
static struct mc_device gdb_mc = {
.list = INIT_LIST_HEAD(gdb_mc.list),
.name = "gdb",
.config = gdb_config,
.remove = gdb_remove,
......
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