Commit 61f36166 authored by Nicholas Bellinger's avatar Nicholas Bellinger

Revert "target: Fix residual overflow handling in target_complete_cmd_with_length"

This reverts commit c1ccbfe0.

Reverting this patch, as it incorrectly assumes the additional length
for INQUIRY in target_complete_cmd_with_length() is SCSI allocation
length, which breaks existing user-space code when SCSI allocation
length is smaller than additional length.

  root@scsi-mq:~# sg_inq --len=4 -vvvv /dev/sdb
  found bsg_major=253
  open /dev/sdb with flags=0x800
      inquiry cdb: 12 00 00 00 04 00
        duration=0 ms
      inquiry: pass-through requested 4 bytes (data-in) but got -28 bytes
      inquiry: pass-through can't get negative bytes, say it got none
      inquiry: got too few bytes (0)
  INQUIRY resid (32) should never exceed requested len=4
      inquiry: failed requesting 4 byte response: Malformed response to
               SCSI command [resid=32]

AFAICT the original change was not to address a specific host issue,
so go ahead and revert to original logic for now.

Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Sumit Rai <sumitrai96@gmail.com>
Cc: stable@vger.kernel.org # 4.8+
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 926317de
...@@ -754,15 +754,7 @@ EXPORT_SYMBOL(target_complete_cmd); ...@@ -754,15 +754,7 @@ EXPORT_SYMBOL(target_complete_cmd);
void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length) void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
{ {
if (scsi_status != SAM_STAT_GOOD) { if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
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) { if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
cmd->residual_count += cmd->data_length - length; cmd->residual_count += cmd->data_length - length;
} else { } else {
...@@ -771,12 +763,6 @@ void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int len ...@@ -771,12 +763,6 @@ void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int len
} }
cmd->data_length = length; 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); target_complete_cmd(cmd, scsi_status);
......
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