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FAILED: patch "[PATCH] tcmu: Fix wrongly calculating of the base_command_size" failed to apply to 3.18-stable tree

PATCH [email protected] 1 participant 1 message Apr 18, 2017

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Stable branch SCSI target SCSI target core user driver
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The patch below does not apply to the 3.18-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From abe342a5b4b5aa579f6bf40ba73447c699e6b579 Mon Sep 17 00:00:00 2001

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

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 <[email protected]>
Reviewed-by Mike Christie <[email protected]>
Signed-off-by Xiubo Li <[email protected]>
Cc [email protected] # 3.18+
Signed-off-by Nicholas Bellinger <[email protected]>
drivers/target/target_core_user.c +8 -2
index e58dfd4fe448..9885d1b521fe 100644
@@ -408,6 +408,13 @@ static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
 	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)
 {

@@ -435,8 +442,7 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
 	 * 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);