Merge tag 'for-5.16/cdrom-2021-10-29' of git://git.kernel.dk/linux-block

Pull CDROM updates from Jens Axboe:
 "On behalf of Phillip, here are the CDROM updates for the 5.16-rc1
  merge window:

   - Add ioctl for improved media change detection (Lukas)

   - Reformat some documentation (Phillip)

   - Redundant variable removal (luo)"

* tag 'for-5.16/cdrom-2021-10-29' of git://git.kernel.dk/linux-block:
  cdrom: Remove redundant variable and its assignment
  cdrom: docs: reformat table in Documentation/userspace-api/ioctl/cdrom.rst
  drivers/cdrom: improved ioctl for media change detection

1 files changed, 57 insertions, 6 deletions

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index bd2e5b1560f5..9877e413fce3 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -344,6 +344,12 @@ static void cdrom_sysctl_register(void);
 
 static LIST_HEAD(cdrom_list);
 
+static void signal_media_change(struct cdrom_device_info *cdi)
+{
+	cdi->mc_flags = 0x3; /* set media changed bits, on both queues */
+	cdi->last_media_change_ms = ktime_to_ms(ktime_get());
+}
+
 int cdrom_dummy_generic_packet(struct cdrom_device_info *cdi,
 			       struct packet_command *cgc)
 {
@@ -616,6 +622,7 @@ int register_cdrom(struct gendisk *disk, struct cdrom_device_info *cdi)
 	ENSURE(cdo, generic_packet, CDC_GENERIC_PACKET);
 	cdi->mc_flags = 0;
 	cdi->options = CDO_USE_FFLAGS;
+	cdi->last_media_change_ms = ktime_to_ms(ktime_get());
 
 	if (autoclose == 1 && CDROM_CAN(CDC_CLOSE_TRAY))
 		cdi->options |= (int) CDO_AUTO_CLOSE;
@@ -864,7 +871,7 @@ static void cdrom_mmc3_profile(struct cdrom_device_info *cdi)
 {
 	struct packet_command cgc;
 	char buffer[32];
-	int ret, mmc3_profile;
+	int mmc3_profile;
 
 	init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_READ);
 
@@ -874,7 +881,7 @@ static void cdrom_mmc3_profile(struct cdrom_device_info *cdi)
 	cgc.cmd[8] = sizeof(buffer);		/* Allocation Length */
 	cgc.quiet = 1;
 
-	if ((ret = cdi->ops->generic_packet(cdi, &cgc)))
+	if (cdi->ops->generic_packet(cdi, &cgc))
 		mmc3_profile = 0xffff;
 	else
 		mmc3_profile = (buffer[6] << 8) | buffer[7];
@@ -1421,8 +1428,7 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
 		cdi->ops->check_events(cdi, 0, slot);
 
 	if (slot == CDSL_NONE) {
-		/* set media changed bits, on both queues */
-		cdi->mc_flags = 0x3;
+		signal_media_change(cdi);
 		return cdrom_load_unload(cdi, -1);
 	}
 
@@ -1455,7 +1461,7 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
 		slot = curslot;
 
 	/* set media changed bits on both queues */
-	cdi->mc_flags = 0x3;
+	signal_media_change(cdi);
 	if ((ret = cdrom_load_unload(cdi, slot)))
 		return ret;
 
@@ -1521,7 +1527,7 @@ int media_changed(struct cdrom_device_info *cdi, int queue)
 	cdi->ioctl_events = 0;
 
 	if (changed) {
-		cdi->mc_flags = 0x3;    /* set bit on both queues */
+		signal_media_change(cdi);
 		ret |= 1;
 		cdi->media_written = 0;
 	}
@@ -2336,6 +2342,49 @@ static int cdrom_ioctl_media_changed(struct cdrom_device_info *cdi,
 	return ret;
 }
 
+/*
+ * Media change detection with timing information.
+ *
+ * arg is a pointer to a cdrom_timed_media_change_info struct.
+ * arg->last_media_change may be set by calling code to signal
+ * the timestamp (in ms) of the last known media change (by the caller).
+ * Upon successful return, ioctl call will set arg->last_media_change
+ * to the latest media change timestamp known by the kernel/driver
+ * and set arg->has_changed to 1 if that timestamp is more recent
+ * than the timestamp set by the caller.
+ */
+static int cdrom_ioctl_timed_media_change(struct cdrom_device_info *cdi,
+		unsigned long arg)
+{
+	int ret;
+	struct cdrom_timed_media_change_info __user *info;
+	struct cdrom_timed_media_change_info tmp_info;
+
+	if (!CDROM_CAN(CDC_MEDIA_CHANGED))
+		return -ENOSYS;
+
+	info = (struct cdrom_timed_media_change_info __user *)arg;
+	cd_dbg(CD_DO_IOCTL, "entering CDROM_TIMED_MEDIA_CHANGE\n");
+
+	ret = cdrom_ioctl_media_changed(cdi, CDSL_CURRENT);
+	if (ret < 0)
+		return ret;
+
+	if (copy_from_user(&tmp_info, info, sizeof(tmp_info)) != 0)
+		return -EFAULT;
+
+	tmp_info.media_flags = 0;
+	if (tmp_info.last_media_change - cdi->last_media_change_ms < 0)
+		tmp_info.media_flags |= MEDIA_CHANGED_FLAG;
+
+	tmp_info.last_media_change = cdi->last_media_change_ms;
+
+	if (copy_to_user(info, &tmp_info, sizeof(*info)) != 0)
+		return -EFAULT;
+
+	return 0;
+}
+
 static int cdrom_ioctl_set_options(struct cdrom_device_info *cdi,
 		unsigned long arg)
 {
@@ -3313,6 +3362,8 @@ int cdrom_ioctl(struct cdrom_device_info *cdi, struct block_device *bdev,
 		return cdrom_ioctl_eject_sw(cdi, arg);
 	case CDROM_MEDIA_CHANGED:
 		return cdrom_ioctl_media_changed(cdi, arg);
+	case CDROM_TIMED_MEDIA_CHANGE:
+		return cdrom_ioctl_timed_media_change(cdi, arg);
 	case CDROM_SET_OPTIONS:
 		return cdrom_ioctl_set_options(cdi, arg);
 	case CDROM_CLEAR_OPTIONS: