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authorJeff Dike <jdike@addtoit.com>2007-02-10 01:44:01 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-11 10:51:21 -0800
commit84f48d4f2b511db15fda67fd38462b91abd0af53 (patch)
tree7de15447387c3ace3dfda3b4dabc0b6d3dd1c643 /arch/um/drivers/mconsole_kern.c
parentd471c0fca7eae1ffd4f7d4c11ee835ff70aaa71f (diff)
downloadop-kernel-dev-84f48d4f2b511db15fda67fd38462b91abd0af53.zip
op-kernel-dev-84f48d4f2b511db15fda67fd38462b91abd0af53.tar.gz
[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: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um/drivers/mconsole_kern.c')
-rw-r--r--arch/um/drivers/mconsole_kern.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 832d5c7..b4dbd102d 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -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
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