[PATCH V2] libata: add horkage for missing Identify Device log

[Damien Le Moal <damien.lemoal@opensource.wdc.com>]

ACS-3 introduced the ATA Identify Device Data log as mandatory. A
warning message currently signals to the user if a device does not
report supporting this log page in the log directory page, regardless
of the ATA version of the device. Furthermore, this warning will appear
for all attempts at accessing this missing log page during device
revalidation.

Since it is useless to constantly access the log directory and warn
about this lack of support once we have discovered that the device
does not support this log page, introduce the horkage flag
ATA_HORKAGE_NO_ID_DEV_LOG to mark a device as lacking support for
the Identify Device Data log page. Set this flag when
ata_log_supported() returns false in ata_identify_page_supported().
The warning is printed only if the device ATA level is 10 or above
(ACS-3 or above), and only once on device scan. With this flag set, the
log directory page is not accessed again to test for Identify Device
Data log page support.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
---
Changes from v1:
* Print the warning only for drives with an ATA version equal to or
  higher than 10 (ACS-3 and above).

 drivers/ata/libata-core.c | 13 ++++++++++++-
 include/linux/libata.h    |  1 +
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 3018ca84a3d8..8a0ccb190d76 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2052,8 +2052,19 @@ static bool ata_identify_page_supported(struct ata_device *dev, u8 page)
 	struct ata_port *ap = dev->link->ap;
 	unsigned int err, i;
 
+	if (dev->horkage & ATA_HORKAGE_NO_ID_DEV_LOG)
+		return false;
+
 	if (!ata_log_supported(dev, ATA_LOG_IDENTIFY_DEVICE)) {
-		ata_dev_warn(dev, "ATA Identify Device Log not supported\n");
+		/*
+		 * IDENTIFY DEVICE data log is defined as mandatory starting
+		 * with ACS-3 (ATA version 10). Warn about the missing log
+		 * for drives which implement this ATA level or above.
+		 */
+		if (ata_id_major_version(dev->id) >= 10)
+			ata_dev_warn(dev,
+				"ATA Identify Device Log not supported\n");
+		dev->horkage |= ATA_HORKAGE_NO_ID_DEV_LOG;
 		return false;
 	}
 
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 5331557316e8..2a8404b26083 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -427,6 +427,7 @@ enum {
 	ATA_HORKAGE_MAX_SEC_1024 = (1 << 25),	/* Limit max sects to 1024 */
 	ATA_HORKAGE_MAX_TRIM_128M = (1 << 26),	/* Limit max trim size to 128M */
 	ATA_HORKAGE_NO_NCQ_ON_ATI = (1 << 27),	/* Disable NCQ on ATI chipset */
+	ATA_HORKAGE_NO_ID_DEV_LOG = (1 << 28),	/* Identify device log missing */
 
 	 /* DMA mask for user DMA control: User visible values; DO NOT
 	    renumber */
-- 
2.31.1