Patch "tcmu: Fix wrongly calculating of the base_command_size" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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 4.9-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-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From abe342a5b4b5aa579f6bf40ba73447c699e6b579 Mon Sep 17 00:00:00 2001
From: Xiubo Li <lixiubo@cmss.chinamobile.com>
Date: Mon, 27 Mar 2017 17:07:41 +0800
Subject: tcmu: Fix wrongly calculating of the base_command_size

From: Xiubo Li <lixiubo@cmss.chinamobile.com>

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.

Tested-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -403,6 +403,13 @@ 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)
 {
@@ -430,8 +437,7 @@ 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 lixiubo@cmss.chinamobile.com are

queue-4.9/tcmu-fix-wrongly-calculating-of-the-base_command_size.patch
queue-4.9/tcmu-fix-possible-overwrite-of-t_data_sg-s-last-iov.patch
queue-4.9/tcmu-skip-data-out-blocks-before-gathering-data-in-buffer-for-bidi-case.patch