[PATCH v2 3/3] ata: sata_mv, avoid trigerrable BUG_ON

From: Jiri Slaby
Date: Tue Jul 09 2019 - 06:02:11 EST

There are several reports that the BUG_ON on unsupported command in
mv_qc_prep can be triggered under some circumstances:

Let sata_mv handle the failure gracefully: warn about that incl. the
failed command number and return an AC_ERR_INVALID error. We can do that
now thanks to the previous patch.

Remove also the long-standing FIXME.

[v2] use %.2x as commands are defined as hexa.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: linux-ide@xxxxxxxxxxxxxxx
Cc: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
drivers/ata/sata_mv.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index d6aac7b31c45..43b9a442ef9f 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -2098,12 +2098,10 @@ static int mv_qc_prep(struct ata_queued_cmd *qc)
* non-NCQ mode are: [RW] STREAM DMA and W DMA FUA EXT, none
* of which are defined/used by Linux. If we get here, this
* driver needs work.
- *
- * FIXME: modify libata to give qc_prep a return value and
- * return error here.
- BUG_ON(tf->command);
- break;
+ ata_port_err(ap, "%s: unsupported command: %.2x\n", __func__,
+ tf->command);
+ return AC_ERR_INVALID;
mv_crqb_pack_cmd(cw++, tf->nsect, ATA_REG_NSECT, 0);
mv_crqb_pack_cmd(cw++, tf->hob_lbal, ATA_REG_LBAL, 0);