FAILED: patch "[PATCH] Revert "libata: Implement support for sense data reporting"" failed to apply to 4.1-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 84ded2f8e7dda336fc2fb3570726ceb3b3b3590f Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Mon, 3 Aug 2015 11:45:34 -0400
Subject: [PATCH] Revert "libata: Implement support for sense data reporting"

This reverts commit fe7173c206de63fc28475ee6ae42ff95c05692de.

As implemented, ACS-4 sense reporting for ATA devices bypasses error
diagnosis and handling in libata degrading EH behavior significantly.
Revert the related changes for now.

ATA_ID_COMMAND_SET_3/4 constants are not reverted as they're used by
later changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: stable@vger.kernel.org #v4.1+

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 426bc12459de..19bcb80b2031 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2147,24 +2147,6 @@ static int ata_dev_config_ncq(struct ata_device *dev,
 	return 0;
 }
 
-static void ata_dev_config_sense_reporting(struct ata_device *dev)
-{
-	unsigned int err_mask;
-
-	if (!ata_id_has_sense_reporting(dev->id))
-		return;
-
-	if (ata_id_sense_reporting_enabled(dev->id))
-		return;
-
-	err_mask = ata_dev_set_feature(dev, SETFEATURE_SENSE_DATA, 0x1);
-	if (err_mask) {
-		ata_dev_dbg(dev,
-			    "failed to enable Sense Data Reporting, Emask 0x%x\n",
-			    err_mask);
-	}
-}
-
 /**
  *	ata_dev_configure - Configure the specified ATA/ATAPI device
  *	@dev: Target device to configure
@@ -2387,7 +2369,7 @@ int ata_dev_configure(struct ata_device *dev)
 					dev->devslp_timing[i] = sata_setting[j];
 				}
 		}
-		ata_dev_config_sense_reporting(dev);
+
 		dev->cdb_len = 16;
 	}
 
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index af08d32af4e0..16125be34893 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1630,70 +1630,6 @@ unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
 }
 
 /**
- *	ata_eh_request_sense - perform REQUEST_SENSE_DATA_EXT
- *	@dev: device to perform REQUEST_SENSE_SENSE_DATA_EXT to
- *	@sense_buf: result sense data buffer (SCSI_SENSE_BUFFERSIZE bytes long)
- *	@dfl_sense_key: default sense key to use
- *
- *	Perform REQUEST_SENSE_DATA_EXT after the device reported CHECK
- *	SENSE.  This function is EH helper.
- *
- *	LOCKING:
- *	Kernel thread context (may sleep).
- *
- *	RETURNS:
- *	encoded sense data on success, 0 on failure or if sense data
- *	is not available.
- */
-static u32 ata_eh_request_sense(struct ata_queued_cmd *qc,
-				struct scsi_cmnd *cmd)
-{
-	struct ata_device *dev = qc->dev;
-	struct ata_taskfile tf;
-	unsigned int err_mask;
-
-	if (!cmd)
-		return 0;
-
-	DPRINTK("ATA request sense\n");
-	ata_dev_warn(dev, "request sense\n");
-	if (!ata_id_sense_reporting_enabled(dev->id)) {
-		ata_dev_warn(qc->dev, "sense data reporting disabled\n");
-		return 0;
-	}
-	ata_tf_init(dev, &tf);
-
-	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
-	tf.flags |= ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
-	tf.command = ATA_CMD_REQ_SENSE_DATA;
-	tf.protocol = ATA_PROT_NODATA;
-
-	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
-	/*
-	 * ACS-4 states:
-	 * The device may set the SENSE DATA AVAILABLE bit to one in the
-	 * STATUS field and clear the ERROR bit to zero in the STATUS field
-	 * to indicate that the command returned completion without an error
-	 * and the sense data described in table 306 is available.
-	 *
-	 * IOW the 'ATA_SENSE' bit might not be set even though valid
-	 * sense data is available.
-	 * So check for both.
-	 */
-	if ((tf.command & ATA_SENSE) ||
-		tf.lbah != 0 || tf.lbam != 0 || tf.lbal != 0) {
-		ata_scsi_set_sense(cmd, tf.lbah, tf.lbam, tf.lbal);
-		qc->flags |= ATA_QCFLAG_SENSE_VALID;
-		ata_dev_warn(dev, "sense data %02x/%02x/%02x\n",
-			     tf.lbah, tf.lbam, tf.lbal);
-	} else {
-		ata_dev_warn(dev, "request sense failed stat %02x emask %x\n",
-			     tf.command, err_mask);
-	}
-	return err_mask;
-}
-
-/**
  *	atapi_eh_request_sense - perform ATAPI REQUEST_SENSE
  *	@dev: device to perform REQUEST_SENSE to
  *	@sense_buf: result sense data buffer (SCSI_SENSE_BUFFERSIZE bytes long)
@@ -1896,22 +1832,7 @@ static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
 		return ATA_EH_RESET;
 	}
 
-	/*
-	 * Sense data reporting does not work if the
-	 * device fault bit is set.
-	 */
-	if ((stat & ATA_SENSE) && !(stat & ATA_DF) &&
-	    !(qc->flags & ATA_QCFLAG_SENSE_VALID)) {
-		if (!(qc->ap->pflags & ATA_PFLAG_FROZEN)) {
-			tmp = ata_eh_request_sense(qc, qc->scsicmd);
-			if (tmp)
-				qc->err_mask |= tmp;
-		} else {
-			ata_dev_warn(qc->dev, "sense data available but port frozen\n");
-		}
-	}
-
-	/* Set by NCQ autosense or request sense above */
+	/* Set by NCQ autosense */
 	if (qc->flags & ATA_QCFLAG_SENSE_VALID)
 		return 0;
 
@@ -2658,15 +2579,14 @@ static void ata_eh_link_report(struct ata_link *link)
 
 #ifdef CONFIG_ATA_VERBOSE_ERROR
 		if (res->command & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ |
-				    ATA_SENSE | ATA_ERR)) {
+				    ATA_ERR)) {
 			if (res->command & ATA_BUSY)
 				ata_dev_err(qc->dev, "status: { Busy }\n");
 			else
-				ata_dev_err(qc->dev, "status: { %s%s%s%s%s}\n",
+				ata_dev_err(qc->dev, "status: { %s%s%s%s}\n",
 				  res->command & ATA_DRDY ? "DRDY " : "",
 				  res->command & ATA_DF ? "DF " : "",
 				  res->command & ATA_DRQ ? "DRQ " : "",
-				  res->command & ATA_SENSE ? "SENSE " : "",
 				  res->command & ATA_ERR ? "ERR " : "");
 		}
 
diff --git a/include/linux/ata.h b/include/linux/ata.h
index 6c78956aa470..0e6a782575b5 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -385,8 +385,6 @@ enum {
 	SATA_SSP		= 0x06,	/* Software Settings Preservation */
 	SATA_DEVSLP		= 0x09,	/* Device Sleep */
 
-	SETFEATURE_SENSE_DATA = 0xC3, /* Sense Data Reporting feature */
-
 	/* feature values for SET_MAX */
 	ATA_SET_MAX_ADDR	= 0x00,
 	ATA_SET_MAX_PASSWD	= 0x01,
@@ -720,20 +718,6 @@ static inline bool ata_id_has_read_log_dma_ext(const u16 *id)
 	return false;
 }
 
-static inline bool ata_id_has_sense_reporting(const u16 *id)
-{
-	if (!(id[ATA_ID_CFS_ENABLE_2] & (1 << 15)))
-		return false;
-	return id[ATA_ID_COMMAND_SET_3] & (1 << 6);
-}
-
-static inline bool ata_id_sense_reporting_enabled(const u16 *id)
-{
-	if (!(id[ATA_ID_CFS_ENABLE_2] & (1 << 15)))
-		return false;
-	return id[ATA_ID_COMMAND_SET_4] & (1 << 6);
-}
-
 /**
  *	ata_id_major_version	-	get ATA level of drive
  *	@id: Identify data