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From:   Lee Duncan <leeman.duncan@gmail.com>
To:     "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Lee Duncan <lduncan@suse.com>, Martin Wilck <mwilck@suse.com>,
        Hannes Reinecke <hare@suse.de>
Subject: [PATCH] scsi: core: Add BLIST_NO_ASK_VPD_SIZE for some VDASD
Date:   Wed, 28 Sep 2022 11:13:50 -0700
Message-Id: <20220928181350.9948-1-leeman.duncan@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Lee Duncan <lduncan@suse.com>

Some storage, such as AIX VDASD (virtual storage) and IBM 2076
(front end) do not like the recent commit:

commit c92a6b5d6335 ("scsi: core: Query VPD size before getting full page")

That commit changed getting SCSI VPD pages so that we now read
just enough of the page to get the actual page size, then read
the whole page in a second read. The problem is that the above
mentioned hardware returns zero for the page size, because of
a firmware error. In such cases, until the firmware is fixed,
this new black flag says to revert to the original method of
reading the VPD pages, i.e. try to read as a whole buffer's
worth on the first try.

Fixes: c92a6b5d6335 ("scsi: core: Query VPD size before getting full page")
Reported-by: Martin Wilck <mwilck@suse.com>
Suggested-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Lee Duncan <lduncan@suse.com>
---
 drivers/scsi/scsi.c         | 14 +++++++++++---
 drivers/scsi/scsi_devinfo.c |  3 ++-
 drivers/scsi/scsi_scan.c    |  3 +++
 include/scsi/scsi_device.h  |  2 ++
 include/scsi/scsi_devinfo.h |  6 +++---
 5 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index c59eac7a32f2..f2db4b846190 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -321,11 +321,19 @@ static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
 	return get_unaligned_be16(&buffer[2]) + 4;
 }
 
-static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
+static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page, int buf_len)
 {
 	unsigned char vpd_header[SCSI_VPD_HEADER_SIZE] __aligned(4);
 	int result;
 
+	/*
+	 * if this hardware is blacklisted then don't bother asking
+	 * the page size, since it will repy with zero -- just assume it
+	 * is the buffer size
+	 */
+	if (sdev->no_ask_vpd_sz_first)
+		return buf_len;
+
 	/*
 	 * Fetch the VPD page header to find out how big the page
 	 * is. This is done to prevent problems on legacy devices
@@ -367,7 +375,7 @@ int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
 	if (!scsi_device_supports_vpd(sdev))
 		return -EINVAL;
 
-	vpd_len = scsi_get_vpd_size(sdev, page);
+	vpd_len = scsi_get_vpd_size(sdev, page, buf_len);
 	if (vpd_len <= 0)
 		return -EINVAL;
 
@@ -402,7 +410,7 @@ static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
 	struct scsi_vpd *vpd_buf;
 	int vpd_len, result;
 
-	vpd_len = scsi_get_vpd_size(sdev, page);
+	vpd_len = scsi_get_vpd_size(sdev, page, SCSI_VPD_PG_LEN);
 	if (vpd_len <= 0)
 		return NULL;
 
diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
index c7080454aea9..d2b2e841e570 100644
--- a/drivers/scsi/scsi_devinfo.c
+++ b/drivers/scsi/scsi_devinfo.c
@@ -134,7 +134,7 @@ static struct {
 	{"3PARdata", "VV", NULL, BLIST_REPORTLUN2},
 	{"ADAPTEC", "AACRAID", NULL, BLIST_FORCELUN},
 	{"ADAPTEC", "Adaptec 5400S", NULL, BLIST_FORCELUN},
-	{"AIX", "VDASD", NULL, BLIST_TRY_VPD_PAGES},
+	{"AIX", "VDASD", NULL, BLIST_TRY_VPD_PAGES | BLIST_NO_ASK_VPD_SIZE},
 	{"AFT PRO", "-IX CF", "0.0>", BLIST_FORCELUN},
 	{"BELKIN", "USB 2 HS-CF", "1.95",  BLIST_FORCELUN | BLIST_INQUIRY_36},
 	{"BROWNIE", "1200U3P", NULL, BLIST_NOREPORTLUN},
@@ -188,6 +188,7 @@ static struct {
 	{"HPE", "OPEN-", "*", BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES},
 	{"IBM", "AuSaV1S2", NULL, BLIST_FORCELUN},
 	{"IBM", "ProFibre 4000R", "*", BLIST_SPARSELUN | BLIST_LARGELUN},
+	{"IBM", "2076", NULL, BLIST_NO_ASK_VPD_SIZE},
 	{"IBM", "2105", NULL, BLIST_RETRY_HWERROR},
 	{"iomega", "jaz 1GB", "J.86", BLIST_NOTQ | BLIST_NOLUN},
 	{"IOMEGA", "ZIP", NULL, BLIST_NOTQ | BLIST_NOLUN},
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 5d27f5196de6..b67743e32089 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1056,6 +1056,9 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 	else if (*bflags & BLIST_SKIP_VPD_PAGES)
 		sdev->skip_vpd_pages = 1;
 
+	if (*bflags & BLIST_NO_ASK_VPD_SIZE)
+		sdev->no_ask_vpd_sz_first = 1;
+
 	transport_configure_device(&sdev->sdev_gendev);
 
 	if (sdev->host->hostt->slave_configure) {
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 2493bd65351a..5d15784ccefc 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -145,6 +145,7 @@ struct scsi_device {
 	const char * model;		/* ... after scan; point to static string */
 	const char * rev;		/* ... "nullnullnullnull" before scan */
 
+#define SCSI_VPD_PG_LEN	255	/* default SCSI VPD page size (max) */
 	struct scsi_vpd __rcu *vpd_pg0;
 	struct scsi_vpd __rcu *vpd_pg83;
 	struct scsi_vpd __rcu *vpd_pg80;
@@ -214,6 +215,7 @@ struct scsi_device {
 					 * creation time */
 	unsigned ignore_media_change:1; /* Ignore MEDIA CHANGE on resume */
 	unsigned silence_suspend:1;	/* Do not print runtime PM related messages */
+	unsigned no_ask_vpd_sz_first:1;	/* Do not ask for VPD size first */
 
 	unsigned int queue_stopped;	/* request queue is quiesced */
 	bool offline_already;		/* Device offline message logged */
diff --git a/include/scsi/scsi_devinfo.h b/include/scsi/scsi_devinfo.h
index 5d14adae21c7..ec12dbaff0e8 100644
--- a/include/scsi/scsi_devinfo.h
+++ b/include/scsi/scsi_devinfo.h
@@ -32,7 +32,8 @@
 #define BLIST_IGN_MEDIA_CHANGE	((__force blist_flags_t)(1ULL << 11))
 /* do not do automatic start on add */
 #define BLIST_NOSTARTONADD	((__force blist_flags_t)(1ULL << 12))
-#define __BLIST_UNUSED_13	((__force blist_flags_t)(1ULL << 13))
+/* do not ask for VPD page size first on some broken targets */
+#define BLIST_NO_ASK_VPD_SIZE	((__force blist_flags_t)(1ULL << 13))
 #define __BLIST_UNUSED_14	((__force blist_flags_t)(1ULL << 14))
 #define __BLIST_UNUSED_15	((__force blist_flags_t)(1ULL << 15))
 #define __BLIST_UNUSED_16	((__force blist_flags_t)(1ULL << 16))
@@ -74,8 +75,7 @@
 #define __BLIST_HIGH_UNUSED (~(__BLIST_LAST_USED | \
 			       (__force blist_flags_t) \
 			       ((__force __u64)__BLIST_LAST_USED - 1ULL)))
-#define __BLIST_UNUSED_MASK (__BLIST_UNUSED_13 | \
-			     __BLIST_UNUSED_14 | \
+#define __BLIST_UNUSED_MASK (__BLIST_UNUSED_14 | \
 			     __BLIST_UNUSED_15 | \
 			     __BLIST_UNUSED_16 | \
 			     __BLIST_UNUSED_24 | \
-- 
2.37.3