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eventfd: change int to __u64 in eventfd_signal()

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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>
This commit is contained in:
Sha Zhengju 2012-05-31 16:26:41 -07:00 • committed by Linus Torvalds
parent 71ca97da9d
commit ee62c6b2dc
2 changed files with 5 additions and 9 deletions
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12
fs/eventfd.c
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@ -46,20 +46,16 @@ struct eventfd_ctx {
* value, and we signal this as overflow condition by returining a POLLERR * value, and we signal this as overflow condition by returining a POLLERR
* to poll(2). * to poll(2).
* *
* Returns @n in case of success, a non-negative number lower than @n in case * Returns the amount by which the counter was incrememnted. This will be less
* of overflow, or the following error codes: * than @n if the counter has overflowed.
*
* -EINVAL : The value of @n is negative.
*/ */
int eventfd_signal(struct eventfd_ctx *ctx, int n) __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
{ {
unsigned long flags; unsigned long flags;
if (n < 0)
return -EINVAL;
spin_lock_irqsave(&ctx->wqh.lock, flags); spin_lock_irqsave(&ctx->wqh.lock, flags);
if (ULLONG_MAX - ctx->count < n) if (ULLONG_MAX - ctx->count < n)
n = (int) (ULLONG_MAX - ctx->count); n = ULLONG_MAX - ctx->count;
ctx->count += n; ctx->count += n;
if (waitqueue_active(&ctx->wqh)) if (waitqueue_active(&ctx->wqh))
wake_up_locked_poll(&ctx->wqh, POLLIN); wake_up_locked_poll(&ctx->wqh, POLLIN);

2
include/linux/eventfd.h
View file

@ -34,7 +34,7 @@ void eventfd_ctx_put(struct eventfd_ctx *ctx);
struct file *eventfd_fget(int fd); struct file *eventfd_fget(int fd);
struct eventfd_ctx *eventfd_ctx_fdget(int fd); struct eventfd_ctx *eventfd_ctx_fdget(int fd);
struct eventfd_ctx *eventfd_ctx_fileget(struct file *file); 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); 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, int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_t *wait,
__u64 *cnt); __u64 *cnt);