From ee62c6b2dc93c09585b51fad18449dc5edb9977f Mon Sep 17 00:00:00 2001
From: Sha Zhengju <handai.szj@taobao.com>
Date: Thu, 31 May 2012 16:26:41 -0700
Subject: [PATCH] eventfd: change int to __u64 in eventfd_signal()
eventfd_ctx->count is an __u64 counter which is allowed to reach
ULLONG_MAX. eventfd_write() adds a __u64 value to "count", but the kernel
side eventfd_signal() only adds an int value to it. Make them consistent.
[akpm@linux-foundation.org: update interface documentation]
Signed-off-by: Sha Zhengju <handai.szj@taobao.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/eventfd.c | 12 ++++--------
include/linux/eventfd.h | 2 +-
2 files changed, 5 insertions(+), 9 deletions(-)
diff --git a/fs/eventfd.c b/fs/eventfd.c
index dba15fecf23e..d81b9f654086 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -46,20 +46,16 @@ struct eventfd_ctx {
* value, and we signal this as overflow condition by returining a POLLERR
* to poll(2).
*
- * Returns @n in case of success, a non-negative number lower than @n in case
- * of overflow, or the following error codes:
- *
- * -EINVAL : The value of @n is negative.
+ * Returns the amount by which the counter was incrememnted. This will be less
+ * than @n if the counter has overflowed.
*/
-int eventfd_signal(struct eventfd_ctx *ctx, int n)
+__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
{
unsigned long flags;
- if (n < 0)
- return -EINVAL;
spin_lock_irqsave(&ctx->wqh.lock, flags);
if (ULLONG_MAX - ctx->count < n)
- n = (int) (ULLONG_MAX - ctx->count);
+ n = ULLONG_MAX - ctx->count;
ctx->count += n;
if (waitqueue_active(&ctx->wqh))
wake_up_locked_poll(&ctx->wqh, POLLIN);
diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
index 91bb4f27238c..3c3ef19a625a 100644
--- a/include/linux/eventfd.h
+++ b/include/linux/eventfd.h
@@ -34,7 +34,7 @@ void eventfd_ctx_put(struct eventfd_ctx *ctx);
struct file *eventfd_fget(int fd);
struct eventfd_ctx *eventfd_ctx_fdget(int fd);
struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
-int eventfd_signal(struct eventfd_ctx *ctx, int n);
+__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt);
int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_t *wait,
__u64 *cnt);