scsi: esp_scsi: Avoid sending ABORT TASK SET messages

If an LLD aborts a task set, it should complete the affected commands
with the appropriate result code. In a couple of cases esp_scsi doesn't
do so.

When the initiator receives an unhandled message, just respond by sending
a MESSAGE REJECT instead of ABORT TASK SET, and thus avoid the issue.

OTOH, a MESSAGE REJECT sent by a target can be taken as an indication
that the initiator messed up somehow. It isn't always possible to abort
correctly, so just fall back on a SCSI bus reset, which will complete the
affected commands with the appropriate result code.

For example, certain Apple (Sony) CD-ROM drives, when the non-existent
LUN 1 is scanned, can't handle the INQUIRY command. The problem is not
detected until the initiator gets a MESSAGE REJECT. Whenever esp_scsi
sees that message, it raises ATN and sends ABORT TASK SET -- but
neglects to complete the failed scmd.

The target then goes into DATA OUT phase (probably bogus), while the ESP
device goes into disconnected mode (surprising, given the bus phase).
The next Transfer Information command from esp_scsi then causes
an Invalid Command interrupt because that command is not valid when in
disconnected mode:

mac_esp: using PDMA for controller 0
mac_esp mac_esp.0: esp0: regs[50f10000:(null)] irq[19]
mac_esp mac_esp.0: esp0: is a ESP236, 16 MHz (ccf=4), SCSI ID 7
scsi host0: esp
scsi 0:0:0:0: Direct-Access     SEAGATE  ST318416N        0010 PQ: 0 ANSI: 3
scsi target0:0:0: Beginning Domain Validation
scsi target0:0:0: asynchronous
scsi target0:0:0: Domain Validation skipping write tests
scsi target0:0:0: Ending Domain Validation
scsi 0:0:3:0: CD-ROM            SONY     CD-ROM CDU-8003A 1.9a PQ: 0 ANSI: 2 CCS
scsi target0:0:3: Beginning Domain Validation
scsi target0:0:3: FAST-5 SCSI 2.0 MB/s ST (500 ns, offset 15)
scsi target0:0:3: Domain Validation skipping write tests
scsi target0:0:3: Ending Domain Validation
scsi host0: unexpected IREG 40
scsi host0: Dumping command log
scsi host0: ent[2] CMD val[c2] sreg[90] seqreg[cc] sreg2[00] ireg[20] ss[01] event[0c]
scsi host0: ent[3] CMD val[00] sreg[91] seqreg[04] sreg2[00] ireg[18] ss[00] event[0c]
scsi host0: ent[4] EVENT val[0d] sreg[91] seqreg[04] sreg2[00] ireg[18] ss[00] event[0c]
scsi host0: ent[5] EVENT val[03] sreg[91] seqreg[04] sreg2[00] ireg[18] ss[00] event[0d]
scsi host0: ent[6] CMD val[90] sreg[91] seqreg[04] sreg2[00] ireg[18] ss[00] event[03]
scsi host0: ent[7] EVENT val[05] sreg[91] seqreg[04] sreg2[00] ireg[18] ss[00] event[03]
scsi host0: ent[8] EVENT val[0d] sreg[93] seqreg[cc] sreg2[00] ireg[10] ss[00] event[05]
scsi host0: ent[9] CMD val[01] sreg[93] seqreg[cc] sreg2[00] ireg[10] ss[00] event[0d]
scsi host0: ent[10] CMD val[11] sreg[93] seqreg[cc] sreg2[00] ireg[10] ss[00] event[0d]
scsi host0: ent[11] EVENT val[0b] sreg[93] seqreg[cc] sreg2[00] ireg[10] ss[00] event[0d]
scsi host0: ent[12] CMD val[12] sreg[97] seqreg[cc] sreg2[00] ireg[08] ss[00] event[0b]
scsi host0: ent[13] EVENT val[0c] sreg[97] seqreg[cc] sreg2[00] ireg[08] ss[00] event[0b]
scsi host0: ent[14] CMD val[44] sreg[90] seqreg[cc] sreg2[00] ireg[20] ss[00] event[0c]
scsi host0: ent[15] CMD val[01] sreg[90] seqreg[cc] sreg2[00] ireg[20] ss[01] event[0c]
scsi host0: ent[16] CMD val[c2] sreg[90] seqreg[cc] sreg2[00] ireg[20] ss[01] event[0c]
scsi host0: ent[17] CMD val[00] sreg[87] seqreg[02] sreg2[00] ireg[18] ss[00] event[0c]
scsi host0: ent[18] EVENT val[0d] sreg[87] seqreg[02] sreg2[00] ireg[18] ss[00] event[0c]
scsi host0: ent[19] EVENT val[06] sreg[87] seqreg[02] sreg2[00] ireg[18] ss[00] event[0d]
scsi host0: ent[20] CMD val[01] sreg[87] seqreg[02] sreg2[00] ireg[18] ss[00] event[06]
scsi host0: ent[21] CMD val[10] sreg[87] seqreg[02] sreg2[00] ireg[18] ss[00] event[06]
scsi host0: ent[22] CMD val[1a] sreg[87] seqreg[ca] sreg2[00] ireg[08] ss[00] event[06]
scsi host0: ent[23] CMD val[12] sreg[87] seqreg[ca] sreg2[00] ireg[08] ss[00] event[06]
scsi host0: ent[24] EVENT val[0d] sreg[87] seqreg[ca] sreg2[00] ireg[08] ss[00] event[06]
scsi host0: ent[25] EVENT val[09] sreg[86] seqreg[ca] sreg2[00] ireg[10] ss[00] event[0d]
scsi host0: ent[26] CMD val[01] sreg[86] seqreg[ca] sreg2[00] ireg[10] ss[00] event[09]
scsi host0: ent[27] CMD val[10] sreg[86] seqreg[ca] sreg2[00] ireg[10] ss[00] event[09]
scsi host0: ent[28] EVENT val[0a] sreg[86] seqreg[ca] sreg2[00] ireg[10] ss[00] event[09]
scsi host0: ent[29] EVENT val[0d] sreg[80] seqreg[ca] sreg2[00] ireg[20] ss[00] event[0a]
scsi host0: ent[30] EVENT val[04] sreg[80] seqreg[ca] sreg2[00] ireg[20] ss[00] event[0d]
scsi host0: ent[31] CMD val[01] sreg[80] seqreg[ca] sreg2[00] ireg[20] ss[00] event[04]
scsi host0: ent[0] CMD val[90] sreg[80] seqreg[ca] sreg2[00] ireg[20] ss[00] event[04]
scsi host0: ent[1] EVENT val[05] sreg[80] seqreg[ca] sreg2[00] ireg[20] ss[00] event[04]
scsi target0:0:3: FAST-5 SCSI 2.0 MB/s ST (500 ns, offset 15)
scsi target0:0:0: asynchronous
sr 0:0:3:0: [sr0] scsi-1 drive
cdrom: Uniform CD-ROM driver Revision: 3.20
sd 0:0:0:0: Attached scsi generic sg0 type 0
sr 0:0:3:0: Attached scsi generic sg1 type 5

This patch resolves this issue because the bus reset causes the INQUIRY
command to fail earlier, and return the appropriate result code.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>