From f303074160d3401970ccae082014e1ee5a9a52c5 Mon Sep 17 00:00:00 2001
From: "Martin K. Petersen" <martin.petersen@oracle.com>
Date: Mon, 4 May 2015 21:54:19 -0400
Subject: libata: Expose TRIM capability in sysfs

Create a sysfs "trim" attribute for each ata_device that displays
whether DSM TRIM is "unsupported", "unqueued", "forced_unqueued"
(blacklisted) or "queued".

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-ata b/Documentation/ABI/testing/sysfs-ata
index 0a93215..9231dae 100644
--- a/Documentation/ABI/testing/sysfs-ata
+++ b/Documentation/ABI/testing/sysfs-ata
@@ -90,6 +90,17 @@ gscr
 	130:	SATA_PMP_GSCR_SII_GPIO
 	Only valid if the device is a PM.
 
+trim
+
+	Shows the DSM TRIM mode currently used by the device. Valid
+	values are:
+	unsupported:		Drive does not support DSM TRIM
+	unqueued:		Drive supports unqueued DSM TRIM only
+	queued:			Drive supports queued DSM TRIM
+	forced_unqueued:	Drive's unqueued DSM support is known to be
+				buggy and only unqueued TRIM commands
+				are sent
+
 spdn_cnt
 
 	Number of time libata decided to lower the speed of link due to errors.
diff --git a/drivers/ata/libata-transport.c b/drivers/ata/libata-transport.c
index 3227b7c..d6c37bc 100644
--- a/drivers/ata/libata-transport.c
+++ b/drivers/ata/libata-transport.c
@@ -560,6 +560,27 @@ show_ata_dev_gscr(struct device *dev,
 
 static DEVICE_ATTR(gscr, S_IRUGO, show_ata_dev_gscr, NULL);
 
+static ssize_t
+show_ata_dev_trim(struct device *dev,
+		  struct device_attribute *attr, char *buf)
+{
+	struct ata_device *ata_dev = transport_class_to_dev(dev);
+	unsigned char *mode;
+
+	if (!ata_id_has_trim(ata_dev->id))
+		mode = "unsupported";
+	else if (ata_dev->horkage & ATA_HORKAGE_NO_NCQ_TRIM)
+			mode = "forced_unqueued";
+	else if (ata_fpdma_dsm_supported(ata_dev))
+		mode = "queued";
+	else
+		mode = "unqueued";
+
+	return snprintf(buf, 20, "%s\n", mode);
+}
+
+static DEVICE_ATTR(trim, S_IRUGO, show_ata_dev_trim, NULL);
+
 static DECLARE_TRANSPORT_CLASS(ata_dev_class,
 			       "ata_device", NULL, NULL, NULL);
 
@@ -733,6 +754,7 @@ struct scsi_transport_template *ata_attach_transport(void)
 	SETUP_DEV_ATTRIBUTE(ering);
 	SETUP_DEV_ATTRIBUTE(id);
 	SETUP_DEV_ATTRIBUTE(gscr);
+	SETUP_DEV_ATTRIBUTE(trim);
 	BUG_ON(count > ATA_DEV_ATTRS);
 	i->dev_attrs[count] = NULL;
 
-- 
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