Re: [PATCH 1/4] fastboot: Asynchronous function calls to speed up kernel boot

Arjan van de Ven
2009-01-04T18:49:05Z

On Sun, 4 Jan 2009 10:33:34 -0800 (PST)
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> IOW, I'd just suggest changing the interface so that
> "async_schedule()" also returns the cookie.
>

>From 6b436c0fab92c50cae7ba3bcd9bcfebf2c9596f7 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sun, 4 Jan 2009 10:47:27 -0800
Subject: [PATCH] fastboot: return the cookie from async_schedule()

Put this code back as suggested by Linus; even if there's no users right
now it makes conceptual sense and the cost is basically zero.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
include/linux/async.h | 2 +-
kernel/async.c | 10 ++++++----
2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/include/linux/async.h b/include/linux/async.h
index b54d83a..678d4fd 100644
--- a/include/linux/async.h
+++ b/include/linux/async.h
@@ -15,7 +15,7 @@
typedef u64 async_cookie_t;
typedef void (async_func_ptr) (void *data, async_cookie_t cookie);

-extern void async_schedule(async_func_ptr *ptr, void *data);
+extern async_cookie_t async_schedule(async_func_ptr *ptr, void *data);
extern void async_synchronize_full(void);
extern void async_synchronize_cookie(async_cookie_t cookie);

diff --git a/kernel/async.c b/kernel/async.c
index 9918fe5..8ecebf5 100644
--- a/kernel/async.c
+++ b/kernel/async.c
@@ -156,32 +156,34 @@ out:
}

-void async_schedule(async_func_ptr *ptr, void *data)
+async_cookie_t async_schedule(async_func_ptr *ptr, void *data)
{
struct async_entry *entry;
unsigned long flags;
+ async_cookie_t newcookie;
+

/* allow irq-off callers */
entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
if (!entry) {
- async_cookie_t newcookie;
spin_lock_irqsave(&async_lock, flags);
newcookie = next_cookie++;
spin_unlock_irqrestore(&async_lock, flags);

/* low on memory.. run synchronously */
ptr(data, newcookie);
- return;
+ return newcookie;
}
entry->func = ptr;
entry->data = data;

spin_lock_irqsave(&async_lock, flags);
- entry->cookie = next_cookie++;
+ newcookie = entry->cookie = next_cookie++;
list_add_tail(&entry->list, &async_pending);
atomic_inc(&entry_count);
spin_unlock_irqrestore(&async_lock, flags);
wake_up(&async_new);
+ return newcookie;
}
EXPORT_SYMBOL_GPL(async_schedule);

--
1.6.0.6

--
Arjan van de Ven Intel Open Source Technology Centre
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