On Thu, Feb 16, 2023 at 04:21:48PM +0200, Oded Gabbay wrote: > On Thu, Feb 16, 2023 at 2:25 PM Stanislaw Gruszka > <stanislaw.grus...@linux.intel.com> wrote: > > > > On Sun, Feb 12, 2023 at 10:44:35PM +0200, Oded Gabbay wrote: > > > From: Tomer Tayar <tta...@habana.ai> > > > > > > When user closes the device file descriptor, it is checked whether the > > > device is still in use, and a message is printed if it is. > > > > I guess this is only for debugging your user-space component? > > Because kernel driver should not make any assumption about > > user-space behavior. Closing whenever user wants should be > > no problem. > First of all, indeed the user can close the device whatever it wants. > We don't limit him, but we do need to track the device state, because > we can't allow a new user to acquire the device until it is idle (due > to h/w limitations). > Therefore, this print is not so much for debug, as it is for letting > the user know the device wasn't idle after he closed it, and > therefore, we are going to reset it to make it idle. > So, it is a notification that is important imo.
This sounds like something that should be handed in open() with -EAGAIN error with eventual message in dmesg. But you know best what info is needed by user-space :-) > > > +static void print_device_in_use_info(struct hl_device *hdev, const char > > > *message) > > > +{ > > > + u32 active_cs_num, dmabuf_export_cnt; > > > + char buf[64], *buf_ptr = buf; > > > + size_t buf_size = sizeof(buf); > > > + bool unknown_reason = true; > > > + > > > + active_cs_num = hl_get_active_cs_num(hdev); > > > + if (active_cs_num) { > > > + unknown_reason = false; > > > + compose_device_in_use_info(&buf_ptr, &buf_size, " [%u > > > active CS]", active_cs_num); > > > + } > > > + > > > + dmabuf_export_cnt = atomic_read(&hdev->dmabuf_export_cnt); > > > + if (dmabuf_export_cnt) { > > > + unknown_reason = false; > > > + compose_device_in_use_info(&buf_ptr, &buf_size, " [%u > > > exported dma-buf]", > > > + dmabuf_export_cnt); > > > + } > > > + > > > + if (unknown_reason) > > > + compose_device_in_use_info(&buf_ptr, &buf_size, " [unknown > > > reason]"); > > > + > > > + dev_notice(hdev->dev, "%s%s\n", message, buf); > > > > why not print counters directly, i.e. "active cs count %u, dmabuf export > > count %u" ? > Because we wanted to print the specific reason, or unknown reason, and > not print all the possible counters in one line, because most of the > time most of the counters will be 0. > We plan to add more reasons so this helper simplifies the code. Ok, just place replace compose_device_in_use_info() with snprintf(). I don't think you need custom implementation of snprintf(). > > > + print_device_in_use_info(hdev, "User process closed FD but > > > device still in use"); > > > hl_device_reset(hdev, HL_DRV_RESET_HARD); > > > > You really need reset here ? > Yes, our h/w requires that we reset the device after the user closed > it. If the device is not idle after the user closed it, we hard reset > it. > If it is idle, we do a more graceful reset. Hmm, ok. Regards Stanislaw