From 9795d8232a24be9e1e1cc408a6bdc01c40e2cedc Mon Sep 17 00:00:00 2001 From: Maximilian Luz Date: Thu, 13 May 2021 15:44:37 +0200 Subject: [PATCH] platform/surface: dtx: Fix poll function The poll function should not return -ERESTARTSYS. Furthermore, locking in this function is completely unnecessary. The ddev->lock protects access to the main device and controller (ddev->dev and ddev->ctrl), ensuring that both are and remain valid while being accessed by clients. Both are, however, never accessed in the poll function. The shutdown test (via atomic bit flags) be safely done without locking, so drop locking here entirely. Reported-by: kernel test robot Fixes: 1d609992832e ("platform/surface: Add DTX driver) Signed-off-by: Maximilian Luz Link: https://lore.kernel.org/r/20210513134437.2431022-1-luzmaximilian@gmail.com Signed-off-by: Hans de Goede --- drivers/platform/surface/surface_dtx.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/drivers/platform/surface/surface_dtx.c b/drivers/platform/surface/surface_dtx.c index 63ce587e79e3..5d9b758a99bb 100644 --- a/drivers/platform/surface/surface_dtx.c +++ b/drivers/platform/surface/surface_dtx.c @@ -527,20 +527,14 @@ static __poll_t surface_dtx_poll(struct file *file, struct poll_table_struct *pt struct sdtx_client *client = file->private_data; __poll_t events = 0; - if (down_read_killable(&client->ddev->lock)) - return -ERESTARTSYS; - - if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &client->ddev->flags)) { - up_read(&client->ddev->lock); + if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &client->ddev->flags)) return EPOLLHUP | EPOLLERR; - } poll_wait(file, &client->ddev->waitq, pt); if (!kfifo_is_empty(&client->buffer)) events |= EPOLLIN | EPOLLRDNORM; - up_read(&client->ddev->lock); return events; }