[PATCH 1/2] ata: libata-scsi: Fix ata_to_sense_error() status handling

[Damien Le Moal <dlemoal@kernel.org>]

Commit 8ae720449fca ("libata: whitespace fixes in ata_to_sense_error()")
inadvertantly added the entry 0x40 (ATA_DRDY) to the stat_table array in
the function ata_to_sense_error(). This entry ties a failed qc which has
a status filed equal to ATA_DRDY to the sense key ILLEGAL REQUEST with
the additional sense code UNALIGNED WRITE COMMAND. This entry will be
used to generate a failed qc sense key and sense code when the qc is
missing sense data and there is no match for the qc error field in the
sense_table array of ata_to_sense_error().

As a result, for a failed qc for which we failed to get sense data (e.g.
read log 10h failed if qc is an NCQ command, or REQUEST SENSE EXT
command failed for the non-ncq case, the user very often end up seeing
the completely misleading "unaligned write command" error, even if qc
was not a write command. E.g.:

sd 0:0:0:0: [sda] tag#12 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s
sd 0:0:0:0: [sda] tag#12 Sense Key : Illegal Request [current]
sd 0:0:0:0: [sda] tag#12 Add. Sense: Unaligned write command
sd 0:0:0:0: [sda] tag#12 CDB: Read(10) 28 00 00 00 10 00 00 00 08 00
I/O error, dev sda, sector 4096 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0

Fix this by removing the ATA_DRDY entry from the stat_table array so
that we default to always returning ABORTED COMMAND without any
additional sense code, since we do not know any better. The entry 0x08
(ATA_DRQ) is also removed since signaling ABORTED COMMAND with a parity
error is also misleading (as a parity error would likely be signaled
through a bus error). So for this case, also default to returning
ABORTED COMMAND without any additional sense code. With this, the
previous example error case becomes:

sd 0:0:0:0: [sda] tag#17 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s
sd 0:0:0:0: [sda] tag#17 Sense Key : Aborted Command [current]
sd 0:0:0:0: [sda] tag#17 Add. Sense: No additional sense information
sd 0:0:0:0: [sda] tag#17 CDB: Read(10) 28 00 00 00 10 00 00 00 08 00
I/O error, dev sda, sector 4096 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0

Together with these fixes, refactor stat_table to make it more readable
by putting the entries comments in front of the entries and using the
defined status bits macros instead of hardcoded values.

Reported-by: Lorenz Brun <lorenz@brun.one>
Reported-by: Brandon Schwartz <Brandon.Schwartz@wdc.com>
Fixes: 8ae720449fca ("libata: whitespace fixes in ata_to_sense_error()")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/ata/libata-scsi.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 27b15176db56..9b16c0f553e0 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -859,18 +859,14 @@ static void ata_to_sense_error(u8 drv_stat, u8 drv_err, u8 *sk, u8 *asc,
 		{0xFF, 0xFF, 0xFF, 0xFF}, // END mark
 	};
 	static const unsigned char stat_table[][4] = {
-		/* Must be first because BUSY means no other bits valid */
-		{0x80,		ABORTED_COMMAND, 0x47, 0x00},
-		// Busy, fake parity for now
-		{0x40,		ILLEGAL_REQUEST, 0x21, 0x04},
-		// Device ready, unaligned write command
-		{0x20,		HARDWARE_ERROR,  0x44, 0x00},
-		// Device fault, internal target failure
-		{0x08,		ABORTED_COMMAND, 0x47, 0x00},
-		// Timed out in xfer, fake parity for now
-		{0x04,		RECOVERED_ERROR, 0x11, 0x00},
-		// Recovered ECC error	  Medium error, recovered
-		{0xFF, 0xFF, 0xFF, 0xFF}, // END mark
+		/* Busy: must be first because BUSY means no other bits valid */
+		{ ATA_BUSY,	ABORTED_COMMAND, 0x00, 0x00 },
+		/* Device fault: INTERNAL TARGET FAILURE */
+		{ ATA_DF,	HARDWARE_ERROR,  0x44, 0x00 },
+		/* Corrected data error */
+		{ ATA_CORR,	RECOVERED_ERROR, 0x00, 0x00 },
+
+		{ 0xFF, 0xFF, 0xFF, 0xFF }, /* END mark */
 	};
 
 	/*
-- 
2.50.1