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Commit 84f48d4f authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

[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: default avatarJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d471c0fc

arch/um/drivers/mconsole_kern.c

+15 −6
Original line number Diff line number Diff line
@@ -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

arch/um/drivers/net_kern.c

+1 −0
Original line number Diff line number Diff line
@@ -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,

arch/um/drivers/ssl.c

+1 −0
Original line number Diff line number Diff line
@@ -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,

arch/um/drivers/ubd_kern.c

+1 −0
Original line number Diff line number Diff line
@@ -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,

arch/um/kernel/tt/gdb_kern.c

+1 −0
Original line number Diff line number Diff line
@@ -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,