[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>
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 832d5c7..b4dbd10 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -337,13 +337,15 @@
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 @@
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 @@
diff /= PAGE_SIZE;
+ down(&plug_mem_mutex);
for(i = 0; i < diff; i++){
struct unplugged_pages *unplugged;
void *addr;
@@ -447,7 +451,7 @@
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 @@
}
err = 0;
+out_unlock:
+ up(&plug_mem_mutex);
out:
return err;
}
@@ -487,6 +493,7 @@
}
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 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 @@
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
diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index eede892..c183864 100644
--- a/arch/um/drivers/net_kern.c
+++ b/arch/um/drivers/net_kern.c
@@ -690,6 +690,7 @@
}
static struct mc_device net_mc = {
+ .list = LIST_HEAD_INIT(net_mc.list),
.name = "eth",
.config = net_config,
.get_config = NULL,
diff --git a/arch/um/drivers/ssl.c b/arch/um/drivers/ssl.c
index 1e82430..fe400ac 100644
--- a/arch/um/drivers/ssl.c
+++ b/arch/um/drivers/ssl.c
@@ -64,6 +64,7 @@
.symlink_from = "serial",
.symlink_to = "tts",
.mc = {
+ .list = LIST_HEAD_INIT(driver.mc.list),
.name = "ssl",
.config = ssl_config,
.get_config = ssl_get_config,
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index f4db97e..c1d40fb 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -828,6 +828,7 @@
* 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,
diff --git a/arch/um/kernel/tt/gdb_kern.c b/arch/um/kernel/tt/gdb_kern.c
index a1af96e..03b06bc 100644
--- a/arch/um/kernel/tt/gdb_kern.c
+++ b/arch/um/kernel/tt/gdb_kern.c
@@ -12,6 +12,7 @@
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,