Patch "tcmu: Fix wrongly calculating of the base_command_size" has been added to the 4.10-stable tree

This is a note to let you know that I've just added the patch titled

tcmu: Fix wrongly calculating of the base_command_size

to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
tcmu-fix-wrongly-calculating-of-the-base_command_size.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Xiubo Li <[email protected]>
Date: Mon, 27 Mar 2017 17:07:41 +0800
Subject: tcmu: Fix wrongly calculating of the base_command_size

From: Xiubo Li <[email protected]>

commit abe342a5b4b5aa579f6bf40ba73447c699e6b579 upstream.

The t_data_nents and t_bidi_data_nents are the numbers of the segments, but it couldn't be sure the block size equals to size of the segment.

For the worst case, all the blocks are discontiguous and there will need the same number of iovecs, that's to say: blocks == iovs. So here just set the number of iovs to block count needed by tcmu cmd.

---
 drivers/target/target_core_user.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

@@ -404,6 +404,13 @@ static inline size_t tcmu_cmd_get_data_l
 	return data_length;
 }
 
+static inline uint32_t tcmu_cmd_get_block_cnt(struct tcmu_cmd *tcmu_cmd)
+{
+	size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
+
+	return data_length / DATA_BLOCK_SIZE;
+}
+
 static sense_reason_t
 tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
 {

@@ -431,8 +438,7 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcm
 	 * expensive to tell how many regions are freed in the bitmap
 	*/
 	base_command_size = max(offsetof(struct tcmu_cmd_entry,
-				req.iov[se_cmd->t_bidi_data_nents +
-					se_cmd->t_data_nents]),
+				req.iov[tcmu_cmd_get_block_cnt(tcmu_cmd)]),
 				sizeof(struct tcmu_cmd_entry));
 	command_size = base_command_size
 		+ round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/tcmu-fix-wrongly-calculating-of-the-base_command_size.patch queue-4.10/tcmu-fix-possible-overwrite-of-t_data_sg-s-last-iov.patch queue-4.10/tcmu-skip-data-out-blocks-before-gathering-data-in-buffer-for-bidi-case.patch