From 535fd072202dbc8afe5a4093178132bdd4ac2424 Mon Sep 17 00:00:00 2001
From: Tom Yan <tom.ty89@gmail.com>
Date: Fri, 22 Jul 2016 02:41:54 +0800
Subject: libata-scsi: fix MODE SELECT translation for Control mode page

scsi_done() was called repeatedly and apparently because of that,
the kernel would call trace when we touch the Control mode page:

Call Trace:
 [<ffffffff812ea0d2>] dump_stack+0x63/0x81
 [<ffffffff81079cfb>] __warn+0xcb/0xf0
 [<ffffffff81079e2d>] warn_slowpath_null+0x1d/0x20
 [<ffffffffa00f51b0>] ata_eh_finish+0xe0/0xf0 [libata]
 [<ffffffffa00fb830>] sata_pmp_error_handler+0x640/0xa50 [libata]
 [<ffffffffa00470ed>] ahci_error_handler+0x1d/0x70 [libahci]
 [<ffffffffa00f55f0>] ata_scsi_port_error_handler+0x430/0x770 [libata]
 [<ffffffffa00eff8d>] ? ata_scsi_cmd_error_handler+0xdd/0x160 [libata]
 [<ffffffffa00f59d7>] ata_scsi_error+0xa7/0xf0 [libata]
 [<ffffffffa00913ba>] scsi_error_handler+0xaa/0x560 [scsi_mod]
 [<ffffffffa0091310>] ? scsi_eh_get_sense+0x180/0x180 [scsi_mod]
 [<ffffffff81098eb8>] kthread+0xd8/0xf0
 [<ffffffff815d913f>] ret_from_fork+0x1f/0x40
 [<ffffffff81098de0>] ? kthread_worker_fn+0x170/0x170
---[ end trace 8b7501047e928a17 ]---

Removed the unnecessary code and let ata_scsi_translate() do the job.

Also, since ata_mselect_control() has no ATA command to send to the
device, ata_scsi_mode_select_xlat() should return 1 for it, so that
ata_scsi_translate() will finish early to avoid ata_qc_issue().

Signed-off-by: Tom Yan <tom.ty89@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 0bc4532..be9c76c 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3701,8 +3701,6 @@ static int ata_mselect_control(struct ata_queued_cmd *qc,
 		dev->flags |= ATA_DFLAG_D_SENSE;
 	else
 		dev->flags &= ~ATA_DFLAG_D_SENSE;
-	qc->scsicmd->result = SAM_STAT_GOOD;
-	qc->scsicmd->scsi_done(qc->scsicmd);
 	return 0;
 }
 
@@ -3829,6 +3827,8 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
 		if (ata_mselect_control(qc, p, pg_len, &fp) < 0) {
 			fp += hdr_len + bd_len;
 			goto invalid_param;
+		} else {
+			goto skip; /* No ATA command to send */
 		}
 		break;
 	default:		/* invalid page code */
-- 
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