Commit f9eca022 authored by Steffen Maier's avatar Steffen Maier Committed by Martin K. Petersen
Browse files

scsi: zfcp: drop duplicate fsf_command from zfcp_fsf_req which is also in QTCB header 



Status read buffers (SRBs, unsolicited notifications) never use a QTCB
[zfcp_fsf_req_create()]. zfcp_fsf_req_send() already uses this to
distinguish SRBs from other FSF request types. We can re-use this method in
zfcp_fsf_req_complete(). Introduce a helper function to make the check for
req->qtcb less magic.

SRBs always are FSF_QTCB_UNSOLICITED_STATUS, so we can hard-code this for
the two trace functions dealing with SRBs.

All other FSF request types have a QTCB and we can get the fsf_command from
there.

zfcp_dbf_hba_fsf_response() and thus zfcp_dbf_hba_fsf_res() are only called
for non-SRB requests so it's safe to dereference the QTCB
[zfcp_fsf_req_complete() returns early on SRB, else calls
zfcp_fsf_protstatus_eval() which calls zfcp_dbf_hba_fsf_response()].  In
zfcp_scsi_forget_cmnd() we guard the QTCB dereference with a preceding NULL
check and rely on boolean shortcut evaluation.

As a side effect, this causes an alignment hole which we can close in
a later patch after having cleaned up all fields of struct zfcp_fsf_req.
Before:
$ pahole -C zfcp_fsf_req drivers/s390/scsi/zfcp.ko
...
	u32                        status;               /*   136     4 */
	u32                        fsf_command;          /*   140     4 */
	struct fsf_qtcb *          qtcb;                 /*   144     8 */
...
After:
$ pahole -C zfcp_fsf_req drivers/s390/scsi/zfcp.ko
...
	u32                        status;               /*   136     4 */
	/* XXX 4 bytes hole, try to pack */
	struct fsf_qtcb *          qtcb;                 /*   144     8 */
...

Signed-off-by: default avatarSteffen Maier <maier@linux.ibm.com>
Reviewed-by: default avatarBenjamin Block <bblock@linux.ibm.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 2c53d8a0

drivers/s390/scsi/zfcp_dbf.c

+4 −4
Original line number Diff line number Diff line
@@ -81,7 +81,7 @@ void zfcp_dbf_hba_fsf_res(char *tag, int level, struct zfcp_fsf_req *req) 
	rec->id = ZFCP_DBF_HBA_RES;

	rec->fsf_req_id = req->req_id;

	rec->fsf_req_status = req->status;

	rec->fsf_cmd = req->fsf_command;

	rec->fsf_cmd = q_head->fsf_command;

	rec->fsf_seq_no = req->seq_no;

	rec->u.res.req_issued = req->issued;

	rec->u.res.prot_status = q_pref->prot_status;
@@ -94,7 +94,7 @@ void zfcp_dbf_hba_fsf_res(char *tag, int level, struct zfcp_fsf_req *req) 
	memcpy(rec->u.res.fsf_status_qual, &q_head->fsf_status_qual,

	       FSF_STATUS_QUALIFIER_SIZE);



	if (req->fsf_command != FSF_QTCB_FCP_CMND) {

	if (q_head->fsf_command != FSF_QTCB_FCP_CMND) {

		rec->pl_len = q_head->log_length;

		zfcp_dbf_pl_write(dbf, (char *)q_pref + q_head->log_start,

				  rec->pl_len, "fsf_res", req->req_id);
@@ -127,7 +127,7 @@ void zfcp_dbf_hba_fsf_uss(char *tag, struct zfcp_fsf_req *req) 
	rec->id = ZFCP_DBF_HBA_USS;

	rec->fsf_req_id = req->req_id;

	rec->fsf_req_status = req->status;

	rec->fsf_cmd = req->fsf_command;

	rec->fsf_cmd = FSF_QTCB_UNSOLICITED_STATUS;



	if (!srb)

		goto log;
@@ -174,7 +174,7 @@ void zfcp_dbf_hba_bit_err(char *tag, struct zfcp_fsf_req *req) 
	rec->id = ZFCP_DBF_HBA_BIT;

	rec->fsf_req_id = req->req_id;

	rec->fsf_req_status = req->status;

	rec->fsf_cmd = req->fsf_command;

	rec->fsf_cmd = FSF_QTCB_UNSOLICITED_STATUS;

	memcpy(&rec->u.be, &sr_buf->payload.bit_error,

	       sizeof(struct fsf_bit_error_payload));

drivers/s390/scsi/zfcp_dbf.h

+2 −2
Original line number Diff line number Diff line
@@ -339,8 +339,8 @@ void zfcp_dbf_hba_fsf_response(struct zfcp_fsf_req *req) 
				      zfcp_dbf_hba_fsf_resp_suppress(req)

				      ? 5 : 1, req);



	} else if ((req->fsf_command == FSF_QTCB_OPEN_PORT_WITH_DID) ||

		   (req->fsf_command == FSF_QTCB_OPEN_LUN)) {

	} else if ((qtcb->header.fsf_command == FSF_QTCB_OPEN_PORT_WITH_DID) ||

		   (qtcb->header.fsf_command == FSF_QTCB_OPEN_LUN)) {

		zfcp_dbf_hba_fsf_resp("fs_open", 4, req);



	} else if (qtcb->header.log_length) {

drivers/s390/scsi/zfcp_def.h

+5 −2
Original line number Diff line number Diff line
@@ -277,7 +277,6 @@ static inline u64 zfcp_scsi_dev_lun(struct scsi_device *sdev) 
 * @qdio_req: qdio queue related values

 * @completion: used to signal the completion of the request

 * @status: status of the request

 * @fsf_command: FSF command issued

 * @qtcb: associated QTCB

 * @seq_no: sequence number of this request

 * @data: private data
@@ -294,7 +293,6 @@ struct zfcp_fsf_req { 
	struct zfcp_qdio_req	qdio_req;

	struct completion	completion;

	u32			status;

	u32			fsf_command;

	struct fsf_qtcb		*qtcb;

	u32			seq_no;

	void			*data;
@@ -311,4 +309,9 @@ int zfcp_adapter_multi_buffer_active(struct zfcp_adapter *adapter) 
	return atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_MB_ACT;

}



static inline bool zfcp_fsf_req_is_status_read_buffer(struct zfcp_fsf_req *req)

{

	return req->qtcb == NULL;

}



#endif /* ZFCP_DEF_H */

drivers/s390/scsi/zfcp_fsf.c

+6 −8
Original line number Diff line number Diff line
@@ -84,13 +84,13 @@ static void zfcp_fsf_class_not_supp(struct zfcp_fsf_req *req) 
void zfcp_fsf_req_free(struct zfcp_fsf_req *req)

{

	if (likely(req->pool)) {

		if (likely(req->qtcb))

		if (likely(!zfcp_fsf_req_is_status_read_buffer(req)))

			mempool_free(req->qtcb, req->adapter->pool.qtcb_pool);

		mempool_free(req, req->pool);

		return;

	}



	if (likely(req->qtcb))

	if (likely(!zfcp_fsf_req_is_status_read_buffer(req)))

		kmem_cache_free(zfcp_fsf_qtcb_cache, req->qtcb);

	kfree(req);

}
@@ -393,7 +393,7 @@ static void zfcp_fsf_protstatus_eval(struct zfcp_fsf_req *req) 
 */

static void zfcp_fsf_req_complete(struct zfcp_fsf_req *req)

{

	if (unlikely(req->fsf_command == FSF_QTCB_UNSOLICITED_STATUS)) {

	if (unlikely(zfcp_fsf_req_is_status_read_buffer(req))) {

		zfcp_fsf_status_read_handler(req);

		return;

	}
@@ -710,7 +710,6 @@ static struct zfcp_fsf_req *zfcp_fsf_req_create(struct zfcp_qdio *qdio, 
	init_completion(&req->completion);



	req->adapter = adapter;

	req->fsf_command = fsf_cmd;

	req->req_id = adapter->req_no;



	if (likely(fsf_cmd != FSF_QTCB_UNSOLICITED_STATUS)) {
@@ -729,10 +728,10 @@ static struct zfcp_fsf_req *zfcp_fsf_req_create(struct zfcp_qdio *qdio, 
		req->qtcb->prefix.req_seq_no = adapter->fsf_req_seq_no;

		req->qtcb->prefix.req_id = req->req_id;

		req->qtcb->prefix.ulp_info = 26;

		req->qtcb->prefix.qtcb_type = fsf_qtcb_type[req->fsf_command];

		req->qtcb->prefix.qtcb_type = fsf_qtcb_type[fsf_cmd];

		req->qtcb->prefix.qtcb_version = FSF_QTCB_CURRENT_VERSION;

		req->qtcb->header.req_handle = req->req_id;

		req->qtcb->header.fsf_command = req->fsf_command;

		req->qtcb->header.fsf_command = fsf_cmd;

	}



	zfcp_qdio_req_init(adapter->qdio, &req->qdio_req, req->req_id, sbtype,
@@ -745,7 +744,6 @@ static int zfcp_fsf_req_send(struct zfcp_fsf_req *req) 
{

	struct zfcp_adapter *adapter = req->adapter;

	struct zfcp_qdio *qdio = adapter->qdio;

	int with_qtcb = (req->qtcb != NULL);

	int req_id = req->req_id;



	zfcp_reqlist_add(adapter->req_list, req);
@@ -761,7 +759,7 @@ static int zfcp_fsf_req_send(struct zfcp_fsf_req *req) 
	}



	/* Don't increase for unsolicited status */

	if (with_qtcb)

	if (!zfcp_fsf_req_is_status_read_buffer(req))

		adapter->fsf_req_seq_no++;

	adapter->req_no++;

drivers/s390/scsi/zfcp_scsi.c

+3 −1
Original line number Diff line number Diff line
@@ -226,7 +226,9 @@ static void zfcp_scsi_forget_cmnd(struct zfcp_fsf_req *old_req, void *data) 
		(struct zfcp_scsi_req_filter *)data;



	/* already aborted - prevent side-effects - or not a SCSI command */

	if (old_req->data == NULL || old_req->fsf_command != FSF_QTCB_FCP_CMND)

	if (old_req->data == NULL ||

	    zfcp_fsf_req_is_status_read_buffer(old_req) ||

	    old_req->qtcb->header.fsf_command != FSF_QTCB_FCP_CMND)

		return;



	/* (tmf_scope == FCP_TMF_TGT_RESET || tmf_scope == FCP_TMF_LUN_RESET) */

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