Re: [RFC 3/3] ata: sata_mv, avoid trigerrable BUG_ON

From: Sergei Shtylyov
Date: Fri Jun 14 2019 - 04:29:46 EST


Hello!

On 14.06.2019 10:11, Jiri Slaby wrote:

There are several reports that the BUG_ON on unsupported command in
mv_qc_prep can be triggered under some circumstances:
https://bugzilla.suse.com/show_bug.cgi?id=1110252
https://serverfault.com/questions/888897/raid-problems-after-power-outage
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1652185
https://bugs.centos.org/view.php?id=14998

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.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: linux-ide@xxxxxxxxxxxxxxx
---
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..144fa0982168 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: %d\n", __func__,
+ tf->command);

I'd use "%x" here instead of "%d".

+ 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);

MBR, Sergei