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From:   =?UTF-8?q?Diego=20Elio=20Petten=C3=B2?= <flameeyes@flameeyes.com>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     =?UTF-8?q?Diego=20Elio=20Petten=C3=B2?= <flameeyes@flameeyes.com>,
        linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: [PATCH 1/2] cdrom: respect device capabilities during opening action
Date:   Tue, 19 Nov 2019 21:37:08 +0000
Message-Id: <20191119213709.10900-1-flameeyes@flameeyes.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Reading the TOC only works if the device can play audio, otherwise
these commands fail (and possibly bring the device to an unhealthy
state.)

Similarly, cdrom_mmc3_profile() should only be called if the device
supports generic packet commands.

To: Jens Axboe <axboe@kernel.dk>
Cc: linux-kernel@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.com>
---
 drivers/cdrom/cdrom.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index ac42ae4651ce..eebdcbef0578 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -996,6 +996,12 @@ static void cdrom_count_tracks(struct cdrom_device_info *cdi, tracktype *tracks)
 	tracks->xa = 0;
 	tracks->error = 0;
 	cd_dbg(CD_COUNT_TRACKS, "entering cdrom_count_tracks\n");
+
+	if (!CDROM_CAN(CDC_PLAY_AUDIO)) {
+		tracks->error = CDS_NO_INFO;
+		return;
+	}
+
 	/* Grab the TOC header so we can see how many tracks there are */
 	ret = cdi->ops->audio_ioctl(cdi, CDROMREADTOCHDR, &header);
 	if (ret) {
@@ -1162,7 +1168,8 @@ int cdrom_open(struct cdrom_device_info *cdi, struct block_device *bdev,
 		ret = open_for_data(cdi);
 		if (ret)
 			goto err;
-		cdrom_mmc3_profile(cdi);
+		if (CDROM_CAN(CDC_GENERIC_PACKET))
+			cdrom_mmc3_profile(cdi);
 		if (mode & FMODE_WRITE) {
 			ret = -EROFS;
 			if (cdrom_open_write(cdi))
@@ -2882,6 +2889,9 @@ int cdrom_get_last_written(struct cdrom_device_info *cdi, long *last_written)
 	   it doesn't give enough information or fails. then we return
 	   the toc contents. */
 use_toc:
+	if (!CDROM_CAN(CDC_PLAY_AUDIO))
+		return -ENOSYS;
+
 	toc.cdte_format = CDROM_MSF;
 	toc.cdte_track = CDROM_LEADOUT;
 	if ((ret = cdi->ops->audio_ioctl(cdi, CDROMREADTOCENTRY, &toc)))
-- 
2.23.0