diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index a4046ca6e60da85d5e0f489ae58981fd5ba45426..6b423485c5d6b4f6e8e54a332f1dd62eda0325d9 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -821,13 +821,15 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
  * in ATA and we need to set TPE=1
  */
 bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
-				       struct request_queue *q, int block_size)
+				       struct request_queue *q)
 {
+	int block_size = queue_logical_block_size(q);
+
 	if (!blk_queue_discard(q))
 		return false;
 
-	attrib->max_unmap_lba_count = (q->limits.max_discard_sectors << 9) /
-								block_size;
+	attrib->max_unmap_lba_count =
+		q->limits.max_discard_sectors >> (ilog2(block_size) - 9);
 	/*
 	 * Currently hardcoded to 1 in Linux/SCSI code..
 	 */
diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index 75f0f08b2a34f32d0b2bfdd35fa40f027e74ae75..79291869bce6c72d9eb4a72fa6d6f5614a104aa4 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -161,8 +161,7 @@ static int fd_configure_device(struct se_device *dev)
 			dev_size, div_u64(dev_size, fd_dev->fd_block_size),
 			fd_dev->fd_block_size);
 
-		if (target_configure_unmap_from_queue(&dev->dev_attrib, q,
-						      fd_dev->fd_block_size))
+		if (target_configure_unmap_from_queue(&dev->dev_attrib, q))
 			pr_debug("IFILE: BLOCK Discard support available,"
 				 " disabled by default\n");
 		/*
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 7c4efb4417b0fc5e9c2cd9700eb83dd024e3db92..2077bc28640a24fa5647430fada0c5d21c64e8e7 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -121,8 +121,7 @@ static int iblock_configure_device(struct se_device *dev)
 	dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
 	dev->dev_attrib.hw_queue_depth = q->nr_requests;
 
-	if (target_configure_unmap_from_queue(&dev->dev_attrib, q,
-					      dev->dev_attrib.hw_block_size))
+	if (target_configure_unmap_from_queue(&dev->dev_attrib, q))
 		pr_debug("IBLOCK: BLOCK Discard support available,"
 			 " disabled by default\n");
 
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index d8ab5101fad5533876339f788b75d855d382bc4f..f6f3bc52c1ac2e21611ba7be2a274c7cb442166d 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -95,6 +95,6 @@ sense_reason_t passthrough_parse_cdb(struct se_cmd *cmd,
 bool target_sense_desc_format(struct se_device *dev);
 sector_t target_to_linux_sector(struct se_device *dev, sector_t lb);
 bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
-				       struct request_queue *q, int block_size);
+				       struct request_queue *q);
 
 #endif /* TARGET_CORE_BACKEND_H */