From: Mike Christie <mchristi@xxxxxxxxxx>
This patch has iblock and file backends pass the WRITE_SAME command to
the device for offloading if possible. It is similar to what is
done for UNMAP/discards, except that we export a large max write same
value to the initiator, and then rely on the block layer to
break it up into multiple requests if it cannot fit into one.
Signed-off-by: Mike Christie <mchristi@xxxxxxxxxx>
---
drivers/target/target_core_file.c | 9 +++++++++
drivers/target/target_core_iblock.c | 4 ++++
drivers/target/target_core_sbc.c | 31 +++++++++++++++++++++++++++++++
include/target/target_core_backend.h | 2 ++
4 files changed, 46 insertions(+)
diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index 75f0f08..df7496a 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -358,6 +358,8 @@ fd_execute_write_same(struct se_cmd *cmd)
{
struct se_device *se_dev = cmd->se_dev;
struct fd_dev *fd_dev = FD_DEV(se_dev);
+ struct file *file = fd_dev->fd_file;
+ struct inode *inode = file->f_mapping->host;
loff_t pos = cmd->t_task_lba * se_dev->dev_attrib.block_size;
sector_t nolb = sbc_get_write_same_sectors(cmd);
struct iov_iter iter;
@@ -385,6 +387,13 @@ fd_execute_write_same(struct se_cmd *cmd)
return TCM_INVALID_CDB_FIELD;
}
+ if (S_ISBLK(inode->i_mode)) {
+ struct block_device *bdev = inode->i_bdev;
+
+ if (bdev_write_same(bdev))
+ return sbc_execute_write_same_direct(bdev, cmd);
+ }
+
bvec = kcalloc(nolb, sizeof(struct bio_vec), GFP_KERNEL);
if (!bvec)
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 2c53dce..44b8ab2 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -415,6 +415,7 @@ iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
static sense_reason_t
iblock_execute_write_same(struct se_cmd *cmd)
{
+ struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
struct iblock_req *ibr;
struct scatterlist *sg;
struct bio *bio;
@@ -439,6 +440,9 @@ iblock_execute_write_same(struct se_cmd *cmd)
return TCM_INVALID_CDB_FIELD;
}
+ if (bdev_write_same(bdev))
+ return sbc_execute_write_same_direct(bdev, cmd);
+
ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
if (!ibr)
goto fail;
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index b83ac37..fe93027 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -217,6 +217,37 @@ sector_t sbc_get_write_same_sectors(struct se_cmd *cmd)
}
EXPORT_SYMBOL(sbc_get_write_same_sectors);
+sense_reason_t sbc_execute_write_same_direct(struct block_device *bdev,
+ struct se_cmd *cmd)
+{
+ struct se_device *dev = cmd->se_dev;
+ struct scatterlist *sg = &cmd->t_data_sg[0];
+ struct page *page = NULL;
+ int ret;
+
+ if (sg->offset) {
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ return TCM_OUT_OF_RESOURCES;
+ sg_copy_to_buffer(sg, cmd->t_data_nents, page_address(page),
+ dev->dev_attrib.block_size);
+ }
+
+ ret = blkdev_issue_write_same(bdev,
+ target_to_linux_sector(dev, cmd->t_task_lba),
+ target_to_linux_sector(dev,
+ sbc_get_write_same_sectors(cmd)),
+ GFP_KERNEL, page ? page : sg_page(sg));
+ if (page)
+ __free_page(page);
+ if (ret)
+ return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+ target_complete_cmd(cmd, GOOD);
+ return 0;
+}
+EXPORT_SYMBOL(sbc_execute_write_same_direct);
+
static sense_reason_t
sbc_execute_write_same_unmap(struct se_cmd *cmd)
{
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 28ee5c2..140309f 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -68,6 +68,8 @@ sense_reason_t sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops);
u32 sbc_get_device_rev(struct se_device *dev);
u32 sbc_get_device_type(struct se_device *dev);
sector_t sbc_get_write_same_sectors(struct se_cmd *cmd);
+sense_reason_t sbc_execute_write_same_direct(struct block_device *bdev,
+ struct se_cmd *cmd);
void sbc_dif_generate(struct se_cmd *);
sense_reason_t sbc_dif_verify(struct se_cmd *, sector_t, unsigned int,
unsigned int, struct scatterlist *, int);
--
1.8.3.1
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