[patch 05/11] zfcp: Fix warnings from smatch

Christof Schmitt
2010-02-17T10:20:23Z

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From: Christof Schmitt <christof.schmitt@de.ibm.com>

The smatch tool from http://repo.or.cz/w/smatch.git warns about this:

drivers/s390/scsi/zfcp_scsi.c +64 zfcp_scsi_command_fail(5) warn: variable dereferenced before check 'scpnt->device'
drivers/s390/scsi/zfcp_scsi.c +64 zfcp_scsi_command_fail(5) warn: variable dereferenced before check 'scpnt->device->host'
drivers/s390/scsi/zfcp_scsi.c +93 zfcp_scsi_queuecommand(23) warn: variable dereferenced before check 'unit'

Fix the first two warnings by removing the checks for scpnt->device
and -> host: As long as the SCSI command exists, there is also a
scsi_device and a Scsi_Host.

Fix the last warning by removing the BUG_ON checks in
zfcp_scsi_queuecommand, they are leftovers from previous paranoia
about wrong pointers between data structures.

Reviewed-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
---

drivers/s390/scsi/zfcp_scsi.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)

diff -urpN linux-2.6/drivers/s390/scsi/zfcp_scsi.c linux-2.6-patched/drivers/s390/scsi/zfcp_scsi.c
--- linux-2.6/drivers/s390/scsi/zfcp_scsi.c 2010-02-16 09:43:29.000000000 +0100
+++ linux-2.6-patched/drivers/s390/scsi/zfcp_scsi.c 2010-02-16 09:43:30.000000000 +0100
@@ -60,10 +60,9 @@ static void zfcp_scsi_command_fail(struc
{
struct zfcp_adapter *adapter =
(struct zfcp_adapter *) scpnt->device->host->hostdata[0];
+
set_host_byte(scpnt, result);
- if ((scpnt->device != NULL) && (scpnt->device->host != NULL))
- zfcp_dbf_scsi_result("fail", 4, adapter->dbf, scpnt, NULL);
- /* return directly */
+ zfcp_dbf_scsi_result("fail", 4, adapter->dbf, scpnt, NULL);
scpnt->scsi_done(scpnt);
}

@@ -87,14 +86,6 @@ static int zfcp_scsi_queuecommand(struct
adapter = (struct zfcp_adapter *) scpnt->device->host->hostdata[0];
unit = scpnt->device->hostdata;

- BUG_ON(!adapter || (adapter != unit->port->adapter));
- BUG_ON(!scpnt->scsi_done);
-
- if (unlikely(!unit)) {
- zfcp_scsi_command_fail(scpnt, DID_NO_CONNECT);
- return 0;
- }
-
scsi_result = fc_remote_port_chkready(rport);
if (unlikely(scsi_result)) {
scpnt->result = scsi_result;