[PATCH] Bluetooth: hci_vhci: Report write readiness with queued input

[PATCH] Bluetooth: hci_vhci: Report write readiness with queued input

[raoxu]

From: Xu Rao <raoxu@uniontech.com>

vhci_poll() returns only EPOLLIN and EPOLLRDNORM when readq is nonempty,
dropping the write readiness bits it reports when the queue is empty.
However, vhci_write() does not wait for readq to drain: incoming frames
are handled independently by vhci_get_user().

As a result, userspace polling only for write readiness can time out or
remain asleep while input is queued, even though it could submit a
frame. Applications that drain input before waiting to write avoid this
case.

Always include EPOLLOUT and EPOLLWRNORM in the readiness mask, and add
EPOLLIN and EPOLLRDNORM when readq contains data. Keep the existing wait
queue registration and empty-queue behavior unchanged.

Signed-off-by: Xu Rao <raoxu@uniontech.com>
---
 drivers/bluetooth/hci_vhci.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
index 771ad9893c44..0b427c65ce59 100644
--- a/drivers/bluetooth/hci_vhci.c
+++ b/drivers/bluetooth/hci_vhci.c
@@ -636,13 +636,14 @@ static ssize_t vhci_write(struct kiocb *iocb, struct iov_iter *from)
 static __poll_t vhci_poll(struct file *file, poll_table *wait)
 {
 	struct vhci_data *data = file->private_data;
+	__poll_t mask = EPOLLOUT | EPOLLWRNORM;

 	poll_wait(file, &data->read_wait, wait);

 	if (!skb_queue_empty(&data->readq))
-		return EPOLLIN | EPOLLRDNORM;
+		mask |= EPOLLIN | EPOLLRDNORM;

-	return EPOLLOUT | EPOLLWRNORM;
+	return mask;
 }

 static void vhci_open_timeout(struct work_struct *work)
--
2.50.1

RE: Bluetooth: hci_vhci: Report write readiness with queued input

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 1606 bytes --]

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/series/1209275/

---Test result---

Test Summary:
CheckPatch                    PASS      0.73 seconds
VerifyFixes                   PASS      0.11 seconds
VerifySignedoff               PASS      0.11 seconds
GitLint                       PASS      0.30 seconds
SubjectPrefix                 PASS      0.10 seconds
BuildKernel                   PASS      31.65 seconds
CheckAllWarning               PASS      35.41 seconds
CheckSparse                   PASS      38.40 seconds
BuildKernel32                 PASS      31.50 seconds
CheckKernelLLVM               PASS      35.55 seconds
TestRunnerSetup               PASS      755.26 seconds
TestRunner_l2cap-tester       PASS      12.53 seconds
TestRunner_iso-tester         PASS      10.83 seconds
TestRunner_bnep-tester        PASS      3.17 seconds
TestRunner_mgmt-tester        PASS      88.63 seconds
TestRunner_rfcomm-tester      PASS      4.55 seconds
TestRunner_sco-tester         PASS      5.69 seconds
TestRunner_ioctl-tester       PASS      4.73 seconds
TestRunner_mesh-tester        PASS      5.57 seconds
TestRunner_smp-tester         PASS      4.41 seconds
TestRunner_userchan-tester    PASS      3.24 seconds
TestRunner_6lowpan-tester     PASS      4.49 seconds
IncrementalBuild              PASS      29.60 seconds



https://github.com/bluez/bluetooth-next/pull/1120

---
Regards,
Linux Bluetooth