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Use more wait_events

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This commit is contained in:
Ruihan Li
2024-09-02 14:54:46 +08:00
committed by Tate, Hongliang Tian
parent bbfc2cd12d
commit f21394c679
3 changed files with 51 additions and 74 deletions
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57
kernel/src/syscall/eventfd.rs
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@ -130,6 +130,28 @@ impl EventFile {
// TODO: deal with overflow logic
}
fn try_read(&self, writer: &mut VmWriter) -> Result<()> {
let mut counter = self.counter.lock();
// Wait until the counter becomes non-zero
if *counter == 0 {
return_errno_with_message!(Errno::EAGAIN, "the counter is zero");
}
// Copy value from counter, and set the new counter value
if self.flags.lock().contains(Flags::EFD_SEMAPHORE) {
writer.write_fallible(&mut 1u64.as_bytes().into())?;
*counter -= 1;
} else {
writer.write_fallible(&mut (*counter).as_bytes().into())?;
*counter = 0;
}
self.update_io_state(&counter);
Ok(())
}
/// Adds val to the counter.
///
/// If the new_value is overflowed or exceeds MAX_COUNTER_VALUE, the counter value
@ -160,40 +182,15 @@ impl Pollable for EventFile {
impl FileLike for EventFile {
fn read(&self, writer: &mut VmWriter) -> Result<usize> {
let read_len = core::mem::size_of::<u64>();
if writer.avail() < read_len {
return_errno_with_message!(Errno::EINVAL, "buf len is less len u64 size");
}
loop {
let mut counter = self.counter.lock();
// Wait until the counter becomes non-zero
if *counter == 0 {
if self.is_nonblocking() {
return_errno_with_message!(Errno::EAGAIN, "try reading event file again");
}
self.update_io_state(&counter);
drop(counter);
let mut poller = Poller::new();
if self.pollee.poll(IoEvents::IN, Some(&mut poller)).is_empty() {
poller.wait()?;
}
continue;
}
// Copy value from counter, and set the new counter value
if self.flags.lock().contains(Flags::EFD_SEMAPHORE) {
writer.write_fallible(&mut 1u64.as_bytes().into())?;
*counter -= 1;
} else {
writer.write_fallible(&mut (*counter).as_bytes().into())?;
*counter = 0;
}
self.update_io_state(&counter);
break;
if self.is_nonblocking() {
self.try_read(writer)?;
} else {
self.wait_events(IoEvents::IN, || self.try_read(writer))?;
}
Ok(read_len)