nvme: set BLK_FEAT_WRITE_ZEROES_UNMAP if device supports DEAC bit

When the device supports the Write Zeroes command and the DEAC bit, it
indicates that the deallocate bit in the Write Zeroes command is
supported, and the bytes read from a deallocated logical block are
zeroes. This means the device supports unmap Write Zeroes, so set the
BLK_FEAT_WRITE_ZEROES_UNMAP feature to the device's queue limit.

Signed-off-by: Zhang Yi <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>

Author: zhangyi089

drivers/nvme/host/core.c

@@ -2420,22 +2420,25 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
 	else
 		lim.write_stream_granularity = 0;
 
-	ret = queue_limits_commit_update(ns->disk->queue, &lim);
-	if (ret) {
-		blk_mq_unfreeze_queue(ns->disk->queue, memflags);
-		goto out;
-	}
-
-	set_capacity_and_notify(ns->disk, capacity);
-
 	/*
 	 * Only set the DEAC bit if the device guarantees that reads from
 	 * deallocated data return zeroes.  While the DEAC bit does not
 	 * require that, it must be a no-op if reads from deallocated data
 	 * do not return zeroes.
 	 */
-	if ((id->dlfeat & 0x7) == 0x1 && (id->dlfeat & (1 << 3)))
+	if ((id->dlfeat & 0x7) == 0x1 && (id->dlfeat & (1 << 3))) {
 		ns->head->features |= NVME_NS_DEAC;
+		if (lim.max_write_zeroes_sectors)
+			lim.features |= BLK_FEAT_WRITE_ZEROES_UNMAP;
+	}
+
+	ret = queue_limits_commit_update(ns->disk->queue, &lim);
+	if (ret) {
+		blk_mq_unfreeze_queue(ns->disk->queue, memflags);
+		goto out;
+	}
+
+	set_capacity_and_notify(ns->disk, capacity);
 	set_disk_ro(ns->disk, nvme_ns_is_readonly(ns, info));
 	set_bit(NVME_NS_READY, &ns->flags);
 	blk_mq_unfreeze_queue(ns->disk->queue, memflags);