Patch "libata: Fall back to unqueued READ LOG EXT if the DMA variant fails" has been added to the 4.1-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    libata: Fall back to unqueued READ LOG EXT if the DMA variant fails

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     libata-fall-back-to-unqueued-read-log-ext-if-the-dma-variant-fails.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 5d3abf8ff67f49271a42c0f7fa4f20f9e046bf0e Mon Sep 17 00:00:00 2001
From: "Martin K. Petersen" <martin.petersen@oracle.com>
Date: Mon, 4 May 2015 21:54:21 -0400
Subject: libata: Fall back to unqueued READ LOG EXT if the DMA variant fails

From: "Martin K. Petersen" <martin.petersen@oracle.com>

commit 5d3abf8ff67f49271a42c0f7fa4f20f9e046bf0e upstream.

Some devices advertise support for the READ/WRITE LOG DMA EXT commands
but fail when we try to issue them. This can lead to queued TRIM being
unintentionally disabled since the relevant feature flag is located in a
general purpose log page.

Fall back to unqueued READ LOG EXT if the DMA variant fails while
reading a log page.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/ata/libata-eh.c |   12 +++++++++++-
 include/linux/libata.h  |    1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1507,13 +1507,17 @@ unsigned int ata_read_log_page(struct at
 {
 	struct ata_taskfile tf;
 	unsigned int err_mask;
+	bool dma = false;
 
 	DPRINTK("read log page - log 0x%x, page 0x%x\n", log, page);
 
+retry:
 	ata_tf_init(dev, &tf);
-	if (dev->dma_mode && ata_id_has_read_log_dma_ext(dev->id)) {
+	if (dev->dma_mode && ata_id_has_read_log_dma_ext(dev->id) &&
+	    !(dev->horkage & ATA_HORKAGE_NO_NCQ_LOG)) {
 		tf.command = ATA_CMD_READ_LOG_DMA_EXT;
 		tf.protocol = ATA_PROT_DMA;
+		dma = true;
 	} else {
 		tf.command = ATA_CMD_READ_LOG_EXT;
 		tf.protocol = ATA_PROT_PIO;
@@ -1527,6 +1531,12 @@ unsigned int ata_read_log_page(struct at
 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
 				     buf, sectors * ATA_SECT_SIZE, 0);
 
+	if (err_mask && dma) {
+		dev->horkage |= ATA_HORKAGE_NO_NCQ_LOG;
+		ata_dev_warn(dev, "READ LOG DMA EXT failed, trying unqueued\n");
+		goto retry;
+	}
+
 	DPRINTK("EXIT, err_mask=%x\n", err_mask);
 	return err_mask;
 }
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -431,6 +431,7 @@ enum {
 	ATA_HORKAGE_NOLPM	= (1 << 20),	/* don't use LPM */
 	ATA_HORKAGE_WD_BROKEN_LPM = (1 << 21),	/* some WDs have broken LPM */
 	ATA_HORKAGE_ZERO_AFTER_TRIM = (1 << 22),/* guarantees zero after trim */
+	ATA_HORKAGE_NO_NCQ_LOG	= (1 << 23),	/* don't use NCQ for log read */
 
 	 /* DMA mask for user DMA control: User visible values; DO NOT
 	    renumber */


Patches currently in stable-queue which might be from martin.petersen@oracle.com are

queue-4.1/libata-fall-back-to-unqueued-read-log-ext-if-the-dma-variant-fails.patch
queue-4.1/libata-expose-trim-capability-in-sysfs.patch
queue-4.1/libata-do-not-blacklist-micron-m500dc.patch
queue-4.1/libata-do-not-blacklist-m510dc.patch