Commit b6364572 authored by Eric Biggers's avatar Eric Biggers Committed by Al Viro
Browse files

eventfd: fold eventfd_ctx_read() into eventfd_read() 



eventfd_ctx_read() is not used outside of eventfd.c, so unexport it and
fold it into eventfd_read().  This slightly simplifies the code and
makes it more analogous to eventfd_write().

(eventfd_ctx_read() was apparently added years ago for KVM irqfd's, but
was never used.)

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 7d815165

fs/eventfd.c

+15 −38
Original line number Diff line number Diff line
@@ -207,36 +207,27 @@ int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *w 
}

EXPORT_SYMBOL_GPL(eventfd_ctx_remove_wait_queue);



/**

 * eventfd_ctx_read - Reads the eventfd counter or wait if it is zero.

 * @ctx: [in] Pointer to eventfd context.

 * @no_wait: [in] Different from zero if the operation should not block.

 * @cnt: [out] Pointer to the 64-bit counter value.

 *

 * Returns %0 if successful, or the following error codes:

 *

 *  - -EAGAIN      : The operation would have blocked but @no_wait was non-zero.

 *  - -ERESTARTSYS : A signal interrupted the wait operation.

 *

 * If @no_wait is zero, the function might sleep until the eventfd internal

 * counter becomes greater than zero.

 */

ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt)

static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,

			    loff_t *ppos)

{

	struct eventfd_ctx *ctx = file->private_data;

	ssize_t res;

	__u64 ucnt = 0;

	DECLARE_WAITQUEUE(wait, current);



	if (count < sizeof(ucnt))

		return -EINVAL;



	spin_lock_irq(&ctx->wqh.lock);

	*cnt = 0;

	res = -EAGAIN;

	if (ctx->count > 0)

		res = 0;

	else if (!no_wait) {

		res = sizeof(ucnt);

	else if (!(file->f_flags & O_NONBLOCK)) {

		__add_wait_queue(&ctx->wqh, &wait);

		for (;;) {

			set_current_state(TASK_INTERRUPTIBLE);

			if (ctx->count > 0) {

				res = 0;

				res = sizeof(ucnt);

				break;

			}

			if (signal_pending(current)) {
@@ -250,31 +241,17 @@ ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt) 
		__remove_wait_queue(&ctx->wqh, &wait);

		__set_current_state(TASK_RUNNING);

	}

	if (likely(res == 0)) {

		eventfd_ctx_do_read(ctx, cnt);

	if (likely(res > 0)) {

		eventfd_ctx_do_read(ctx, &ucnt);

		if (waitqueue_active(&ctx->wqh))

			wake_up_locked_poll(&ctx->wqh, POLLOUT);

	}

	spin_unlock_irq(&ctx->wqh.lock);



	return res;

}

EXPORT_SYMBOL_GPL(eventfd_ctx_read);



static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,

			    loff_t *ppos)

{

	struct eventfd_ctx *ctx = file->private_data;

	ssize_t res;

	__u64 cnt;

	if (res > 0 && put_user(ucnt, (__u64 __user *)buf))

		return -EFAULT;



	if (count < sizeof(cnt))

		return -EINVAL;

	res = eventfd_ctx_read(ctx, file->f_flags & O_NONBLOCK, &cnt);

	if (res < 0)

	return res;



	return put_user(cnt, (__u64 __user *) buf) ? -EFAULT : sizeof(cnt);

}



static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t count,

include/linux/eventfd.h

+0 −7
Original line number Diff line number Diff line
@@ -36,7 +36,6 @@ struct file *eventfd_fget(int fd); 
struct eventfd_ctx *eventfd_ctx_fdget(int fd);

struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);

__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_entry_t *wait,

				  __u64 *cnt);
@@ -62,12 +61,6 @@ static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) 


}



static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait,

				       __u64 *cnt)

{

	return -ENOSYS;

}



static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,

						wait_queue_entry_t *wait, __u64 *cnt)

{

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