David Howells wrote:
Dominik Brodowski <[EMAIL PROTECTED]> wrote:
Add functions down_read_interruptible, and down_write_interruptible to rw
semaphores. Implement these for i386.
...
+static inline int
+rwsem_down_interruptible_failed_common(struct rw_semaphore *sem,
+ struct rwsem_waiter *waiter, signed long adjustment)
+{
...
I wonder if you should check to see if there are any readers that can be woken
up if a sleeping writer is interrupted, but I can't think of a simple way to
do it.
I think it will, won't it?
-struct rw_semaphore fastcall __sched *
-rwsem_down_read_failed(struct rw_semaphore *sem)
+void fastcall __sched rwsem_down_read_failed(struct rw_semaphore *sem)
Please don't.
@@ -199,14 +253,33 @@ rwsem_down_read_failed(struct rw_semapho
RWSEM_WAITING_BIAS - RWSEM_ACTIVE_BIAS);
rwsemtrace(sem, "Leaving rwsem_down_read_failed");
- return sem;
Ditto.
-struct rw_semaphore fastcall __sched *
-rwsem_down_write_failed(struct rw_semaphore *sem)
+void fastcall __sched rwsem_down_write_failed(struct rw_semaphore *sem)
Ditto.
@@ -216,10 +289,31 @@ rwsem_down_write_failed(struct rw_semaph
rwsem_down_failed_common(sem, &waiter, -RWSEM_ACTIVE_BIAS);
rwsemtrace(sem, "Leaving rwsem_down_write_failed");
- return sem;
Ditto.
@@ -99,11 +103,12 @@ static inline void __down_read(struct rw
{
__asm__ __volatile__(
"# beginning down_read\n\t"
-LOCK_PREFIX " incl (%%eax)\n\t" /* adds 0x00000001, returns the old
value */
+LOCK_PREFIX " incl %0\n\t" /* adds 0x00000001, returns the old value
*/
Ditto.
" js 2f\n\t" /* jump if we weren't granted the lock */
"1:\n\t"
LOCK_SECTION_START("")
"2:\n\t"
+ " movl %2,%%eax\n\t"
Splat.
" pushl %%ecx\n\t"
" pushl %%edx\n\t"
" call rwsem_down_read_failed\n\t"
Splat.
@@ -113,11 +118,41 @@ LOCK_PREFIX " incl (%%eax)\n\t" /*
LOCK_SECTION_END
"# ending down_read\n\t"
: "=m"(sem->count)
- : "a"(sem), "m"(sem->count)
+ : "m"(sem->count), "m"(sem)
: "memory", "cc");
}
You appear to be corrupting EAX.
+static inline int __down_read_interruptible(struct rw_semaphore *sem)
Will corrupt EAX.
I'll fix these up. You're right by the looks.
"# beginning down_write\n\t"
-LOCK_PREFIX " xadd %%edx,(%%eax)\n\t" /* subtract 0x0000ffff, returns
the old value */
+LOCK_PREFIX " xadd %%edx,%0\n\t" /* subtract 0x0000ffff, returns the
old value */
Again, please don't. It's a lot more readable when it mentions EAX directly,
plus it's also independent of constraint reordering.
OK I suppose so...
-
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