diff --git a/drivers/hv/mshv_vtl_main.c b/drivers/hv/mshv_vtl_main.c index 2b40c9e3bf88..1ffa904837b3 100644 --- a/drivers/hv/mshv_vtl_main.c +++ b/drivers/hv/mshv_vtl_main.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -448,12 +449,35 @@ static void mshv_vtl_cancel(int cpu) static int mshv_vtl_poll_file_wake(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key) { struct mshv_vtl_poll_file *poll_file = container_of(wait, struct mshv_vtl_poll_file, wait); + __poll_t pollflags = key_to_poll(key); + + if (pollflags & POLLFREE) + list_del_init(&wait->entry); mshv_vtl_cancel(poll_file->cpu); + if (pollflags & POLLFREE) { + /* Publish teardown last; pair with acquire in the removal path. */ + smp_store_release(&poll_file->wqh, NULL); + } + return 0; } +static void mshv_vtl_poll_file_remove_wait_queue(struct mshv_vtl_poll_file *poll_file) +{ + wait_queue_head_t *wqh; + + /* POLLFREE providers RCU-delay the waitqueue free. */ + rcu_read_lock(); + /* Pair with the release store in the POLLFREE callback. */ + wqh = smp_load_acquire(&poll_file->wqh); + if (wqh) + remove_wait_queue(wqh, &poll_file->wait); + rcu_read_unlock(); + WRITE_ONCE(poll_file->wqh, NULL); +} + static void mshv_vtl_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, poll_table *pt) { struct mshv_vtl_poll_file *poll_file = container_of(pt, struct mshv_vtl_poll_file, pt); @@ -490,9 +514,7 @@ static int mshv_vtl_ioctl_set_poll_file(struct mshv_vtl_set_poll_file __user *us mutex_lock(&mshv_vtl_poll_file_lock); - if (poll_file->wqh) - remove_wait_queue(poll_file->wqh, &poll_file->wait); - poll_file->wqh = NULL; + mshv_vtl_poll_file_remove_wait_queue(poll_file); old_file = poll_file->file; poll_file->file = file;