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Diffstat (limited to 'fs/eventfd.c')
-rw-r--r--fs/eventfd.c20
1 files changed, 11 insertions, 9 deletions
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 5de2c2db3aa..91c0829a703 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -28,6 +28,7 @@ struct eventfd_ctx {
* issue a wakeup.
*/
__u64 count;
+ unsigned int flags;
};
/*
@@ -87,22 +88,20 @@ static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
{
struct eventfd_ctx *ctx = file->private_data;
ssize_t res;
- __u64 ucnt;
+ __u64 ucnt = 0;
DECLARE_WAITQUEUE(wait, current);
if (count < sizeof(ucnt))
return -EINVAL;
spin_lock_irq(&ctx->wqh.lock);
res = -EAGAIN;
- ucnt = ctx->count;
- if (ucnt > 0)
+ if (ctx->count > 0)
res = sizeof(ucnt);
else if (!(file->f_flags & O_NONBLOCK)) {
__add_wait_queue(&ctx->wqh, &wait);
for (res = 0;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (ctx->count > 0) {
- ucnt = ctx->count;
res = sizeof(ucnt);
break;
}
@@ -117,8 +116,9 @@ static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
__remove_wait_queue(&ctx->wqh, &wait);
__set_current_state(TASK_RUNNING);
}
- if (res > 0) {
- ctx->count = 0;
+ if (likely(res > 0)) {
+ ucnt = (ctx->flags & EFD_SEMAPHORE) ? 1 : ctx->count;
+ ctx->count -= ucnt;
if (waitqueue_active(&ctx->wqh))
wake_up_locked(&ctx->wqh);
}
@@ -166,7 +166,7 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
__remove_wait_queue(&ctx->wqh, &wait);
__set_current_state(TASK_RUNNING);
}
- if (res > 0) {
+ if (likely(res > 0)) {
ctx->count += ucnt;
if (waitqueue_active(&ctx->wqh))
wake_up_locked(&ctx->wqh);
@@ -207,7 +207,7 @@ SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);
BUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);
- if (flags & ~(EFD_CLOEXEC | EFD_NONBLOCK))
+ if (flags & ~EFD_FLAGS_SET)
return -EINVAL;
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
@@ -216,13 +216,14 @@ SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
init_waitqueue_head(&ctx->wqh);
ctx->count = count;
+ ctx->flags = flags;
/*
* When we call this, the initialization must be complete, since
* anon_inode_getfd() will install the fd.
*/
fd = anon_inode_getfd("[eventfd]", &eventfd_fops, ctx,
- flags & (O_CLOEXEC | O_NONBLOCK));
+ flags & EFD_SHARED_FCNTL_FLAGS);
if (fd < 0)
kfree(ctx);
return fd;
@@ -232,3 +233,4 @@ SYSCALL_DEFINE1(eventfd, unsigned int, count)
{
return sys_eventfd2(count, 0);
}
+