[PATCH for review] [109/145] x86_64: Convert modlist_lock to be a raw spinlock

Andi Kleen
2006-08-10T19:43:00Z

r

This is a preparationary patch for converting stacktrace over to the
new dwarf2 unwinder. lockdep uses stacktrace and the new unwinder
takes the modlist_lock so using a normal spinlock would cause a deadlock.
Use a raw lock instead.

Cc: mingo@elte.hu

Signed-off-by: Andi Kleen <ak@suse.de>

---
kernel/module.c | 42 ++++++++++++++++++++++++++----------------
1 files changed, 26 insertions(+), 16 deletions(-)

Index: linux/kernel/module.c
===================================================================
--- linux.orig/kernel/module.c
+++ linux/kernel/module.c
@@ -59,7 +59,7 @@
#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))

/* Protects module list */
-static DEFINE_SPINLOCK(modlist_lock);
+static raw_spinlock_t modlist_lock = __RAW_SPIN_LOCK_UNLOCKED;

/* List of modules, protected by module_mutex AND modlist_lock */
static DEFINE_MUTEX(module_mutex);
@@ -751,11 +751,13 @@ void __symbol_put(const char *symbol)
unsigned long flags;
const unsigned long *crc;

- spin_lock_irqsave(&modlist_lock, flags);
+ raw_local_save_flags(flags);
+ __raw_spin_lock(&modlist_lock);
if (!__find_symbol(symbol, &owner, &crc, 1))
BUG();
module_put(owner);
- spin_unlock_irqrestore(&modlist_lock, flags);
+ __raw_spin_unlock(&modlist_lock);
+ raw_local_irq_restore(flags);
}
EXPORT_SYMBOL(__symbol_put);

@@ -1134,11 +1136,13 @@ void *__symbol_get(const char *symbol)
unsigned long value, flags;
const unsigned long *crc;

- spin_lock_irqsave(&modlist_lock, flags);
+ raw_local_save_flags(flags);
+ __raw_spin_lock(&modlist_lock);
value = __find_symbol(symbol, &owner, &crc, 1);
if (value && !strong_try_module_get(owner))
value = 0;
- spin_unlock_irqrestore(&modlist_lock, flags);
+ __raw_spin_unlock(&modlist_lock);
+ raw_local_irq_restore(flags);

return (void *)value;
}
@@ -2141,7 +2145,8 @@ const struct exception_table_entry *sear
const struct exception_table_entry *e = NULL;
struct module *mod;

- spin_lock_irqsave(&modlist_lock, flags);
+ raw_local_save_flags(flags);
+ __raw_spin_lock(&modlist_lock);
list_for_each_entry(mod, &modules, list) {
if (mod->num_exentries == 0)
continue;
@@ -2152,7 +2157,8 @@ const struct exception_table_entry *sear
if (e)
break;
}
- spin_unlock_irqrestore(&modlist_lock, flags);
+ __raw_spin_unlock(&modlist_lock);
+ raw_local_irq_restore(flags);

/* Now, if we found one, we are running inside it now, hence
we cannot unload the module, hence no refcnt needed. */
@@ -2166,19 +2172,20 @@ int is_module_address(unsigned long addr
{
unsigned long flags;
struct module *mod;
+ int ret = 0;

- spin_lock_irqsave(&modlist_lock, flags);
-
+ raw_local_save_flags(flags);
+ __raw_spin_lock(&modlist_lock);
list_for_each_entry(mod, &modules, list) {
if (within(addr, mod->module_core, mod->core_size)) {
- spin_unlock_irqrestore(&modlist_lock, flags);
- return 1;
+ ret = 1;
+ break;
}
}
+ __raw_spin_unlock(&modlist_lock);
+ raw_local_irq_restore(flags);

- spin_unlock_irqrestore(&modlist_lock, flags);
-
- return 0;
+ return ret;
}

@@ -2199,9 +2206,12 @@ struct module *module_text_address(unsig
struct module *mod;
unsigned long flags;

- spin_lock_irqsave(&modlist_lock, flags);
+ /* This is called from lockdep */
+ raw_local_save_flags(flags);
+ __raw_spin_lock(&modlist_lock);
mod = __module_text_address(addr);
- spin_unlock_irqrestore(&modlist_lock, flags);
+ __raw_spin_unlock(&modlist_lock);
+ raw_local_irq_restore(flags);

return mod;
}