From c1ccbfe0311e2380a6d2dcb0714b36904f5d586f Mon Sep 17 00:00:00 2001
From: Sumit Rai <sumitrai96@gmail.com>
Date: Wed, 20 Jul 2016 13:59:42 -0700
Subject: [PATCH] target: Fix residual overflow handling in
target_complete_cmd_with_length
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This patch fixes residual overflow handling to correctly set the
residual_count using SPDTL, instead of SCSI Allocation Length.
Allocation Length is the maximum value of the SPDTL and not substitute
for it, hence it shouldn’t be used to calculate ResidualCount except for
cases where SPDTL > Allocation Length and Data is truncated (in that
case both Alloc Len and SPDTL are same). (SPC 5r01 Section 4.2.5.6).
Thanks to Ajay Nair in assisting with this patch.
Signed-off-by: Sumit Rai <sumitrai96@gmail.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/target/target_core_transport.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 42c2a44b83dd..6094a6beddde 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -754,7 +754,15 @@ EXPORT_SYMBOL(target_complete_cmd);
void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
{
- if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
+ if (scsi_status != SAM_STAT_GOOD) {
+ return;
+ }
+
+ /*
+ * Calculate new residual count based upon length of SCSI data
+ * transferred.
+ */
+ if (length < cmd->data_length) {
if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
cmd->residual_count += cmd->data_length - length;
} else {
@@ -763,6 +771,12 @@ void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int len
}
cmd->data_length = length;
+ } else if (length > cmd->data_length) {
+ cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
+ cmd->residual_count = length - cmd->data_length;
+ } else {
+ cmd->se_cmd_flags &= ~(SCF_OVERFLOW_BIT | SCF_UNDERFLOW_BIT);
+ cmd->residual_count = 0;
}
target_complete_cmd(cmd, scsi_status);
--
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