From: Chip Coldwell <coldwell@redhat.com>
Subject: [PATCH RHEL-5] 2/2 bz237889 SPI DV fixup
Date: Mon, 7 May 2007 15:42:58 -0400 (EDT)
Bugzilla: 237889
Message-Id: <Pine.LNX.4.64.0705071534100.3723@bogart.boston.redhat.com>
Changelog: [scsi] SPI DV fixup



This is the second of two unrelated patches associated with one bugzilla, 
237889.  This one fixes a problem with SPI domain validation.  Quoting 
from the bugzilla:

"Domain Validation tests are starting with a sync factor that is too fast 
for devices attached to U320 controllers.  Due to this problem, some end 
devices will be sent with a negotiation rate higher than what is 
supported, resulting in commands timing out, or settling with a 
negotiation less than its capabable of. This problem is due to the spi 
transport layer settling for the max and min sync rates provided by the 
scsi lld driver, containing the bios negotition default parameters.  The 
mpt fusion sometimes reports U320 speeds in the bios settings for all 
devices, even those that are not capable of those speeds.

This patch solves this problem by taking into account the capabilities of 
the end device based on parameters provided in the inquiry data."

The "spi_dv_in_progress" checks a bit flag, and so is KABI neutral.

Upstream in Linus' git tree; compiles and runs here.
    
    commit dfdc58ba354adb80d67c99f7be84f95a8e02e466
    Author: James Bottomley <James.Bottomley@steeleye.com>
    Date:   Wed Sep 20 12:00:18 2006 -0400
    
        [SCSI] SPI transport class: misc DV fixes
    
        Key more of the domain validation settings off the inquiry data from
        the disk (in particular, don't try IU or DT unless the disk claims to
        support them.
    
        Also add a new dv_in_progress flag to prevent recursive DV.
    
        Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

diff --git a/drivers/scsi/scsi_transport_spi.c b/drivers/scsi/scsi_transport_spi.c
index 7afe87b..5409b46 100644
--- a/drivers/scsi/scsi_transport_spi.c
+++ b/drivers/scsi/scsi_transport_spi.c
@@ -47,6 +47,7 @@
 
 /* Private data accessors (keep these out of the header file) */
 #define spi_dv_pending(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_pending)
+#define spi_dv_in_progress(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_in_progress)
 #define spi_dv_mutex(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_mutex)
 
 struct spi_internal {
@@ -240,6 +241,7 @@ static int spi_setup_transport_attrs(struct transport_container *tc,
 	spi_pcomp_en(starget) = 0;
 	spi_hold_mcs(starget) = 0;
 	spi_dv_pending(starget) = 0;
+	spi_dv_in_progress(starget) = 0;
 	spi_initial_dv(starget) = 0;
 	mutex_init(&spi_dv_mutex(starget));
 
@@ -830,28 +832,37 @@ spi_dv_device_internal(struct scsi_device *sdev, u8 *buffer)
 	DV_SET(period, spi_min_period(starget));
 	/* try QAS requests; this should be harmless to set if the
 	 * target supports it */
-	if (scsi_device_qas(sdev))
+	if (scsi_device_qas(sdev)) {
 		DV_SET(qas, 1);
-	/* Also try IU transfers */
-	if (scsi_device_ius(sdev))
+	} else {
+		DV_SET(qas, 0);
+	}
+
+	if (scsi_device_ius(sdev) && spi_min_period(starget) < 9) {
+		/* This u320 (or u640). Set IU transfers */
 		DV_SET(iu, 1);
-	if (spi_min_period(starget) < 9) {
-		/* This u320 (or u640). Ignore the coupled parameters
-		 * like DT and IU, but set the optional ones */
+		/* Then set the optional parameters */
 		DV_SET(rd_strm, 1);
 		DV_SET(wr_flow, 1);
 		DV_SET(rti, 1);
 		if (spi_min_period(starget) == 8)
 			DV_SET(pcomp_en, 1);
+	} else {
+		DV_SET(iu, 0);
 	}
+
 	/* now that we've done all this, actually check the bus
 	 * signal type (if known).  Some devices are stupid on
 	 * a SE bus and still claim they can try LVD only settings */
 	if (i->f->get_signalling)
 		i->f->get_signalling(shost);
 	if (spi_signalling(shost) == SPI_SIGNAL_SE ||
-	    spi_signalling(shost) == SPI_SIGNAL_HVD)
+	    spi_signalling(shost) == SPI_SIGNAL_HVD ||
+	    !scsi_device_dt(sdev)) {
 		DV_SET(dt, 0);
+	} else {
+		DV_SET(dt, 1);
+	}
 	/* Do the read only INQUIRY tests */
 	spi_dv_retrain(sdev, buffer, buffer + sdev->inquiry_len,
 		       spi_dv_device_compare_inquiry);
@@ -907,6 +918,10 @@ spi_dv_device(struct scsi_device *sdev)
 	if (unlikely(scsi_device_get(sdev)))
 		return;
 
+	if (unlikely(spi_dv_in_progress(starget)))
+		return;
+	spi_dv_in_progress(starget) = 1;
+
 	buffer = kzalloc(len, GFP_KERNEL);
 
 	if (unlikely(!buffer))
@@ -938,6 +953,7 @@ spi_dv_device(struct scsi_device *sdev)
  out_free:
 	kfree(buffer);
  out_put:
+	spi_dv_in_progress(starget) = 0;
 	scsi_device_put(sdev);
 }
 EXPORT_SYMBOL(spi_dv_device);
diff --git a/include/scsi/scsi_transport_spi.h b/include/scsi/scsi_transport_spi.h
index 302680c..da180f7 100644
--- a/include/scsi/scsi_transport_spi.h
+++ b/include/scsi/scsi_transport_spi.h
@@ -53,7 +53,8 @@ struct spi_transport_attrs {
 	unsigned int support_ius; /* support Information Units */
 	unsigned int support_qas; /* supports quick arbitration and selection */
 	/* Private Fields */
-	unsigned int dv_pending:1; /* Internal flag */
+	unsigned int dv_pending:1; /* Internal flag: DV Requested */
+	unsigned int dv_in_progress:1;	/* Internal: DV started */
 	struct mutex dv_mutex; /* semaphore to serialise dv */
 };
 

-- 
Charles M. "Chip" Coldwell
Senior Software Engineer
Red Hat, Inc
978-392-2426