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authorJames Bottomley <JBottomley@Parallels.com>2012-07-25 23:55:55 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-09-14 10:00:32 -0700
commitd3ed1731ba6bca32ac0ac96377cae8fd735e16e6 (patch)
treed0d470c33b743c71ea39df269bcafe4feffe5b4c
parent7a4601c0bfde4ed50c54f30c32c5677e3daec4f9 (diff)
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SCSI: Fix 'Device not ready' issue on mpt2sas
commit 14216561e164671ce147458653b1fea06a4ada1e upstream. This is a particularly nasty SCSI ATA Translation Layer (SATL) problem. SAT-2 says (section 8.12.2) if the device is in the stopped state as the result of processing a START STOP UNIT command (see 9.11), then the SATL shall terminate the TEST UNIT READY command with CHECK CONDITION status with the sense key set to NOT READY and the additional sense code of LOGICAL UNIT NOT READY, INITIALIZING COMMAND REQUIRED; mpt2sas internal SATL seems to implement this. The result is very confusing standby behaviour (using hdparm -y). If you suspend a drive and then send another command, usually it wakes up. However, if the next command is a TEST UNIT READY, the SATL sees that the drive is suspended and proceeds to follow the SATL rules for this, returning NOT READY to all subsequent commands. This means that the ordering of TEST UNIT READY is crucial: if you send TUR and then a command, you get a NOT READY to both back. If you send a command and then a TUR, you get GOOD status because the preceeding command woke the drive. This bit us badly because commit 85ef06d1d252f6a2e73b678591ab71caad4667bb Author: Tejun Heo <tj@kernel.org> Date: Fri Jul 1 16:17:47 2011 +0200 block: flush MEDIA_CHANGE from drivers on close(2) Changed our ordering on TEST UNIT READY commands meaning that SATA drives connected to an mpt2sas now suspend and refuse to wake (because the mpt2sas SATL sees the suspend *before* the drives get awoken by the next ATA command) resulting in lots of failed commands. The standard is completely nuts forcing this inconsistent behaviour, but we have to work around it. The fix for this is twofold: 1. Set the allow_restart flag so we wake the drive when we see it has been suspended 2. Return all TEST UNIT READY status directly to the mid layer without any further error handling which prevents us causing error handling which may offline the device just because of a media check TUR. Reported-by: Matthias Prager <linux@matthiasprager.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/scsi/scsi_error.c10
-rw-r--r--drivers/scsi/scsi_scan.c10
2 files changed, 20 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index cc8dc8cc6d6..b3f0b0f6d44 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -42,6 +42,8 @@
#include <trace/events/scsi.h>
+static void scsi_eh_done(struct scsi_cmnd *scmd);
+
#define SENSE_TIMEOUT (10*HZ)
/*
@@ -241,6 +243,14 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
if (! scsi_command_normalize_sense(scmd, &sshdr))
return FAILED; /* no valid sense data */
+ if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
+ /*
+ * nasty: for mid-layer issued TURs, we need to return the
+ * actual sense data without any recovery attempt. For eh
+ * issued ones, we need to try to recover and interpret
+ */
+ return SUCCESS;
+
if (scsi_sense_is_deferred(&sshdr))
return NEEDS_RETRY;
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 8906557d2a2..348840e8092 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -776,6 +776,16 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
sdev->model = (char *) (sdev->inquiry + 16);
sdev->rev = (char *) (sdev->inquiry + 32);
+ if (strncmp(sdev->vendor, "ATA ", 8) == 0) {
+ /*
+ * sata emulation layer device. This is a hack to work around
+ * the SATL power management specifications which state that
+ * when the SATL detects the device has gone into standby
+ * mode, it shall respond with NOT READY.
+ */
+ sdev->allow_restart = 1;
+ }
+
if (*bflags & BLIST_ISROM) {
sdev->type = TYPE_ROM;
sdev->removable = 1;