[PATCH 10/14] scsi: sd: Move WRITE_ZEROES configuration to a separate function

From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: linux-scsi@vger.kernel.org
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Subject: [PATCH 10/14] scsi: sd: Move WRITE_ZEROES configuration to a separate function
Date: Wed,  2 Mar 2022 00:35:55 -0500	[thread overview]
Message-ID: <20220302053559.32147-11-martin.petersen@oracle.com> (raw)
In-Reply-To: <20220302053559.32147-1-martin.petersen@oracle.com>

In preparation for adding support for the WRITE SAME(16) NDOB flag,
move configuration of the WRITE_ZEROES operation to a separate
function. This is done to facilitate fetching all VPD pages before
choosing the appropriate zeroing method for a given device.

The deferred configuration also allows us to mirror the discard
behavior and permit the user to revert a device to the kernel default
configuration by echoing "default" to the sysfs file.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
 drivers/scsi/sd.c | 56 +++++++++++++++++++++++++++++++++--------------
 drivers/scsi/sd.h |  7 ++++--
 2 files changed, 44 insertions(+), 19 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index eae5c81ae515..ee4f4aea5f0f 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -101,6 +101,7 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_ZBC);
 #define SD_MINORS	16
 
 static void sd_config_discard(struct scsi_disk *, enum sd_lbp_mode);
+static void sd_config_write_zeroes(struct scsi_disk *, enum sd_zeroing_mode);
 static void sd_config_write_same(struct scsi_disk *);
 static int  sd_revalidate_disk(struct gendisk *);
 static void sd_unlock_native_capacity(struct gendisk *disk);
@@ -428,10 +429,12 @@ static DEVICE_ATTR_RW(provisioning_mode);
 
 /* sysfs_match_string() requires dense arrays */
 static const char *zeroing_mode[] = {
+	[SD_ZERO_DEFAULT]	= "default",
 	[SD_ZERO_WRITE]		= "write",
 	[SD_ZERO_WS]		= "writesame",
 	[SD_ZERO_WS16_UNMAP]	= "writesame_16_unmap",
 	[SD_ZERO_WS10_UNMAP]	= "writesame_10_unmap",
+	[SD_ZERO_DISABLE]	= "disabled",
 };
 
 static ssize_t
@@ -457,7 +460,12 @@ zeroing_mode_store(struct device *dev, struct device_attribute *attr,
 	if (mode < 0)
 		return -EINVAL;
 
-	sdkp->zeroing_mode = mode;
+	if (mode == SD_ZERO_DEFAULT)
+		sdkp->zeroing_override = false;
+	else
+		sdkp->zeroing_override = true;
+
+	sd_config_write_zeroes(sdkp, mode);
 
 	return count;
 }
@@ -1049,6 +1057,31 @@ static blk_status_t sd_setup_write_same10_cmnd(struct scsi_cmnd *cmd,
 	return scsi_alloc_sgtables(cmd);
 }
 
+static void sd_config_write_zeroes(struct scsi_disk *sdkp,
+				   enum sd_zeroing_mode mode)
+{
+	struct request_queue *q = sdkp->disk->queue;
+	unsigned int logical_block_size = sdkp->device->sector_size;
+
+	if (mode == SD_ZERO_DEFAULT && !sdkp->zeroing_override) {
+		if (sdkp->lbprz && sdkp->lbpws)
+			mode = SD_ZERO_WS16_UNMAP;
+		else if (sdkp->lbprz && sdkp->lbpws10)
+			mode = SD_ZERO_WS10_UNMAP;
+		else if (sdkp->max_ws_blocks)
+			mode = SD_ZERO_WS;
+		else
+			mode = SD_ZERO_WRITE;
+	}
+
+	if (mode == SD_ZERO_DISABLE)
+		sdkp->zeroing_override = true;
+
+	sdkp->zeroing_mode = mode;
+	blk_queue_max_write_zeroes_sectors(q, sdkp->max_ws_blocks *
+					   (logical_block_size >> 9));
+}
+
 static blk_status_t sd_setup_write_zeroes_cmnd(struct scsi_cmnd *cmd)
 {
 	struct request *rq = scsi_cmd_to_rq(cmd);
@@ -1079,12 +1112,11 @@ static blk_status_t sd_setup_write_zeroes_cmnd(struct scsi_cmnd *cmd)
 
 static void sd_config_write_same(struct scsi_disk *sdkp)
 {
-	struct request_queue *q = sdkp->disk->queue;
 	unsigned int logical_block_size = sdkp->device->sector_size;
 
 	if (sdkp->device->no_write_same) {
 		sdkp->max_ws_blocks = 0;
-		goto out;
+		return;
 	}
 
 	/* Some devices can not handle block counts above 0xffff despite
@@ -1103,15 +1135,6 @@ static void sd_config_write_same(struct scsi_disk *sdkp)
 		sdkp->max_ws_blocks = 0;
 	}
 
-	if (sdkp->lbprz && sdkp->lbpws)
-		sdkp->zeroing_mode = SD_ZERO_WS16_UNMAP;
-	else if (sdkp->lbprz && sdkp->lbpws10)
-		sdkp->zeroing_mode = SD_ZERO_WS10_UNMAP;
-	else if (sdkp->max_ws_blocks)
-		sdkp->zeroing_mode = SD_ZERO_WS;
-	else
-		sdkp->zeroing_mode = SD_ZERO_WRITE;
-
 	if (sdkp->max_ws_blocks &&
 	    sdkp->physical_block_size > logical_block_size) {
 		/*
@@ -1131,10 +1154,6 @@ static void sd_config_write_same(struct scsi_disk *sdkp)
 				   bytes_to_logical(sdkp->device,
 						    sdkp->physical_block_size));
 	}
-
-out:
-	blk_queue_max_write_zeroes_sectors(q, sdkp->max_ws_blocks *
-					 (logical_block_size >> 9));
 }
 
 static blk_status_t sd_setup_flush_cmnd(struct scsi_cmnd *cmd)
@@ -2126,6 +2145,8 @@ static int sd_done(struct scsi_cmnd *SCpnt)
 			case WRITE_SAME:
 				if (SCpnt->cmnd[1] & 8) { /* UNMAP */
 					sd_config_discard(sdkp, SD_LBP_DISABLE);
+					sd_config_write_zeroes(sdkp,
+							       SD_ZERO_DISABLE);
 				} else {
 					sdkp->device->no_write_same = 1;
 					sd_config_write_same(sdkp);
@@ -3352,7 +3373,9 @@ static int sd_revalidate_disk(struct gendisk *disk)
 		sd_read_write_same(sdkp, buffer);
 		sd_read_security(sdkp, buffer);
 		sd_read_cpr(sdkp);
+		sd_config_write_same(sdkp);
 		sd_config_discard(sdkp, SD_LBP_DEFAULT);
+		sd_config_write_zeroes(sdkp, SD_ZERO_DEFAULT);
 	}
 
 	/*
@@ -3398,7 +3421,6 @@ static int sd_revalidate_disk(struct gendisk *disk)
 	sdkp->first_scan = 0;
 
 	set_capacity_and_notify(disk, logical_to_sectors(sdp, sdkp->capacity));
-	sd_config_write_same(sdkp);
 	kfree(buffer);
 
 	/*
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 57a8241163c5..e0ee4215a3b4 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -61,11 +61,13 @@ enum sd_lbp_mode {
 	SD_LBP_DISABLE,		/* Discard disabled due to failed cmd */
 };
 
-enum {
-	SD_ZERO_WRITE = 0,	/* Use WRITE(10/16) command */
+enum sd_zeroing_mode {
+	SD_ZERO_DEFAULT = 0,	/* Default mode based on what device reports */
+	SD_ZERO_WRITE,		/* Use WRITE(10/16) command */
 	SD_ZERO_WS,		/* Use WRITE SAME(10/16) command */
 	SD_ZERO_WS16_UNMAP,	/* Use WRITE SAME(16) with UNMAP */
 	SD_ZERO_WS10_UNMAP,	/* Use WRITE SAME(10) with UNMAP */
+	SD_ZERO_DISABLE,	/* Write Zeroes disabled due to failed cmd */
 };
 
 struct scsi_disk {
@@ -111,6 +113,7 @@ struct scsi_disk {
 	u8		nr_actuators;		/* Number of actuators */
 	bool		lblvpd;
 	bool		provisioning_override;
+	bool		zeroing_override;
 	unsigned	ATO : 1;	/* state of disk ATO bit */
 	unsigned	cache_override : 1; /* temp override of WCE,RCD */
 	unsigned	WCE : 1;	/* state of disk WCE bit */
-- 
2.32.0

