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From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>,
	"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
	Chuck Lever <chuck.lever@oracle.com>,
	linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
	target-devel@vger.kernel.org, linux-nfs@vger.kernel.org
Subject: [PATCH 2/7] sd: implement ->get_unique_id
Date: Tue, 12 Oct 2021 14:04:40 +0200	[thread overview]
Message-ID: <20211012120445.861860-3-hch@lst.de> (raw)
In-Reply-To: <20211012120445.861860-1-hch@lst.de>

Add the method to query for a uniqueue ID of a given type by looking
it up in the cached device identification VPD page.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index d8f6add416c0a..ea1489d3e8497 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1757,6 +1757,42 @@ static void sd_rescan(struct device *dev)
 	sd_revalidate_disk(sdkp->disk);
 }
 
+static int sd_get_unique_id(struct gendisk *disk, u8 id[16], u8 type)
+{
+	struct scsi_device *sdev = scsi_disk(disk)->device;
+	const struct scsi_vpd *vpd;
+	const unsigned char *d;
+	int len = -ENXIO;
+
+	rcu_read_lock();
+	vpd = rcu_dereference(sdev->vpd_pg83);
+	if (!vpd)
+		goto out_unlock;
+
+	len = -EINVAL;
+	for (d = vpd->data + 4; d < vpd->data + vpd->len; d += d[3] + 4) {
+		/* we only care about designators with LU association */
+		if (((d[1] >> 4) & 0x3) != 0x00)
+			continue;
+		if ((d[1] & 0xf) != type)
+			continue;
+
+		/*
+		 * Only exit early if a 16-byte descriptor was found.  Otherwise
+		 * keep looking as one with more entropy might still show up.
+		 */
+		len = d[3];
+		if (len != 8 && len != 12 && len != 16)
+			continue;
+		memcpy(id, d + 4, len);
+		if (len == 16)
+			break;
+	}
+out_unlock:
+	rcu_read_unlock();
+	return len;
+}
+
 static char sd_pr_type(enum pr_type type)
 {
 	switch (type) {
@@ -1861,6 +1897,7 @@ static const struct block_device_operations sd_fops = {
 	.check_events		= sd_check_events,
 	.unlock_native_capacity	= sd_unlock_native_capacity,
 	.report_zones		= sd_zbc_report_zones,
+	.get_unique_id		= sd_get_unique_id,
 	.pr_ops			= &sd_pr_ops,
 };
 
-- 
2.30.2


  parent reply	other threads:[~2021-10-12 12:08 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-12 12:04 remove QUEUE_FLAG_SCSI_PASSTHROUGH Christoph Hellwig
2021-10-12 12:04 ` [PATCH 1/7] block: add a ->get_unique_id method Christoph Hellwig
2021-10-12 17:03   ` Bart Van Assche
2021-10-14  7:31   ` Hannes Reinecke
2021-10-12 12:04 ` Christoph Hellwig [this message]
2021-10-12 13:13   ` [PATCH 2/7] sd: implement ->get_unique_id Keith Busch
2021-10-14  7:30   ` Hannes Reinecke
2021-10-14  8:01     ` Christoph Hellwig
2021-10-14  8:03       ` Christoph Hellwig
2021-10-12 12:04 ` [PATCH 3/7] nfsd/blocklayout: use ->get_unique_id instead of sending SCSI commands Christoph Hellwig
2021-10-12 13:06   ` J. Bruce Fields
2021-10-14  7:32   ` Hannes Reinecke
2021-10-12 12:04 ` [PATCH 4/7] bsg-lib: initialize the bsg_job in bsg_transport_sg_io_fn Christoph Hellwig
2021-10-14  7:33   ` Hannes Reinecke
2021-10-12 12:04 ` [PATCH 5/7] scsi: add a scsi_alloc_request helper Christoph Hellwig
2021-10-14  7:37   ` Hannes Reinecke
2021-10-12 12:04 ` [PATCH 6/7] block: remove the initialize_rq_fn blk_mq_ops method Christoph Hellwig
2021-10-14  7:38   ` Hannes Reinecke
2021-10-12 12:04 ` [PATCH 7/7] block: remove QUEUE_FLAG_SCSI_PASSTHROUGH Christoph Hellwig
2021-10-14  7:38   ` Hannes Reinecke
2021-10-19  7:54 remove QUEUE_FLAG_SCSI_PASSTHROUGH v2 Christoph Hellwig
2021-10-19  7:54 ` [PATCH 2/7] sd: implement ->get_unique_id Christoph Hellwig
2021-10-21  6:06 remove QUEUE_FLAG_SCSI_PASSTHROUGH v3 Christoph Hellwig
2021-10-21  6:06 ` [PATCH 2/7] sd: implement ->get_unique_id Christoph Hellwig
2021-10-21 13:34   ` Hannes Reinecke

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