Subject: Re: [PATCH 6/8] csiostor: Chelsio FCoE offload driver submission (headers part 1).

From: Naresh Kumar Inna <[email-masked]>
Date: Sat, 25 Aug 2012 00:06:07 +0530

On 8/24/2012 1:28 AM, Nicholas A. Bellinger wrote:
> On Fri, 2012-08-24 at 03:57 +0530, Naresh Kumar Inna wrote:
>> This patch contains the first set of the header files for csiostor driver.
>>
>> Signed-off-by: Naresh Kumar Inna <[email-masked]>
>> ---
>>  drivers/scsi/csiostor/csio_defs.h       |  143 ++++++
>>  drivers/scsi/csiostor/csio_fcoe_proto.h |  843 +++++++++++++++++++++++++++++++
>>  drivers/scsi/csiostor/csio_hw.h         |  668 ++++++++++++++++++++++++
>>  drivers/scsi/csiostor/csio_init.h       |  158 ++++++
>>  4 files changed, 1812 insertions(+), 0 deletions(-)
>>  create mode 100644 drivers/scsi/csiostor/csio_defs.h
>>  create mode 100644 drivers/scsi/csiostor/csio_fcoe_proto.h
>>  create mode 100644 drivers/scsi/csiostor/csio_hw.h
>>  create mode 100644 drivers/scsi/csiostor/csio_init.h
>>
> 
> Hi Naresh,
> 
> Just commenting on csio_defs.h bits here...  As Robert mentioned, you'll
> need to convert the driver to use (or add to) upstream protocol
> definitions and drop the csio_fcoe_proto.h bits..
> 

Hi Nicholas,

I would like take up the discussion of the protocol header file in that
email thread. Please find the rest of my replies inline.

Thanks for reviewing,
Naresh.

>> diff --git a/drivers/scsi/csiostor/csio_defs.h b/drivers/scsi/csiostor/csio_defs.h
>> new file mode 100644
>> index 0000000..4f1c713
>> --- /dev/null
>> +++ b/drivers/scsi/csiostor/csio_defs.h
>> @@ -0,0 +1,143 @@
>> +/*
>> + * This file is part of the Chelsio FCoE driver for Linux.
>> + *
>> + * Copyright (c) 2008-2012 Chelsio Communications, Inc. All rights reserved.
>> + *
>> + * This software is available to you under a choice of one of two
>> + * licenses.  You may choose to be licensed under the terms of the GNU
>> + * General Public License (GPL) Version 2, available from the file
>> + * COPYING in the main directory of this source tree, or the
>> + * OpenIB.org BSD license below:
>> + *
>> + *     Redistribution and use in source and binary forms, with or
>> + *     without modification, are permitted provided that the following
>> + *     conditions are met:
>> + *
>> + *      - Redistributions of source code must retain the above
>> + *        copyright notice, this list of conditions and the following
>> + *        disclaimer.
>> + *
>> + *      - Redistributions in binary form must reproduce the above
>> + *        copyright notice, this list of conditions and the following
>> + *        disclaimer in the documentation and/or other materials
>> + *        provided with the distribution.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
>> + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
>> + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
>> + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
>> + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
>> + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
>> + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
>> + * SOFTWARE.
>> + */
>> +
>> +#ifndef __CSIO_DEFS_H__
>> +#define __CSIO_DEFS_H__
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/timer.h>
>> +#include <linux/list.h>
>> +#include <linux/bug.h>
>> +#include <linux/pci.h>
>> +#include <linux/jiffies.h>
>> +
>> +/* Function returns */
>> +enum csio_retval {
>> +	CSIO_SUCCESS = 0,
>> +	CSIO_INVAL = 1,
>> +	CSIO_BUSY = 2,
>> +	CSIO_NOSUPP = 3,
>> +	CSIO_TIMEOUT = 4,
>> +	CSIO_NOMEM = 5,
>> +	CSIO_NOPERM = 6,
>> +	CSIO_RETRY = 7,
>> +	CSIO_EPROTO = 8,
>> +	CSIO_EIO = 9,
>> +	CSIO_CANCELLED = 10,
>> +};
>> +
> 
> Please don't assign macros for errno's, and give them positive values.
>

Although some of these return values appear to be mapped to errno
values, there are others that do not have an errno equivalent (example
CSIO_CANCELLED). We may have future needs to have more driver/protocol
specific return values as well. What do you suggest?

>> +#define csio_retval_t enum csio_retval
> 
> Please get rid of this csio_retval_t nonsense.

I can get rid of the typedef and use enum csio_retval instead.

> 
>> +
>> +enum {
>> +	CSIO_FALSE = 0,
>> +	CSIO_TRUE = 1,
>> +};
>> +
> 
> Same here, please use normal Boolean macros
> 
>> +#define CSIO_ROUNDUP(__v, __r)		(((__v) + (__r) - 1) / (__r))
>> +#define CSIO_INVALID_IDX		0xFFFFFFFF
>> +#define csio_inc_stats(elem, val)	((elem)->stats.val++)
>> +#define csio_dec_stats(elem, val)	((elem)->stats.val--)
> 
> No reason for either of this stats inc+dec macros.  Please drop them.

I will get rid of them.

> 
>> +#define csio_valid_wwn(__n)		((*__n >> 4) == 0x5 ? CSIO_TRUE : \
>> +						CSIO_FALSE)
>> +#define CSIO_WORD_TO_BYTE		4
>> +
>> +static inline int
>> +csio_list_deleted(struct list_head *list)
>> +{
>> +	return ((list->next == list) && (list->prev == list));
>> +}
>> +
>> +#define csio_list_next(elem)	(((struct list_head *)(elem))->next)
>> +#define csio_list_prev(elem)	(((struct list_head *)(elem))->prev)
>> +
>> +#define csio_deq_from_head(head, elem)					  \
>> +do {									  \
>> +	if (!list_empty(head)) {					  \
>> +		*((struct list_head **)(elem)) = csio_list_next((head));  \
>> +		csio_list_next((head)) =				  \
>> +				csio_list_next(csio_list_next((head)));   \
>> +		csio_list_prev(csio_list_next((head))) = (head);	  \
>> +		INIT_LIST_HEAD(*((struct list_head **)(elem)));	          \
>> +	} else								  \
>> +		*((struct list_head **)(elem)) = (struct list_head *)NULL;\
>> +} while (0)
>> +
> 
> This code is confusing as hell..  Why can't you just use normal list.h
> macros for this..?  

I have not found an equivalent function in list.h that does the above
and the following macro. Could you please point me to it? I have seen a
couple of other drivers define their own macros to achieve what this
macro does, hence I assumed there isnt a list.h macro that does this.

>> +#define csio_deq_from_tail(head, elem)					  \
>> +do {									  \
>> +	if (!list_empty(head)) {					  \
>> +		*((struct list_head **)(elem)) = csio_list_prev((head));  \
>> +		csio_list_prev((head)) =				  \
>> +				csio_list_prev(csio_list_prev((head)));	  \
>> +		csio_list_next(csio_list_prev((head))) = (head);	  \
>> +		INIT_LIST_HEAD(*((struct list_head **)(elem)));		  \
>> +	} else								  \
>> +		*((struct list_head **)(elem)) = (struct list_head *)NULL;\
>> +} while (0)
>> +
> 
> Same here..  Please don't use macros like this.
> 
>> +/* State machine */
>> +typedef void (*csio_sm_state_t)(void *, uint32_t);
>> +
>> +struct csio_sm {
>> +	struct list_head	sm_list;
>> +	csio_sm_state_t		sm_state;
>> +};
>> +
>> +#define csio_init_state(__smp, __state)					\
>> +	(((struct csio_sm *)(__smp))->sm_state = (csio_sm_state_t)(__state))
>> +
>> +#define	csio_set_state(__smp, __state)					\
>> +	(((struct csio_sm *)(__smp))->sm_state = (csio_sm_state_t)(__state))
>> +
>> +
>> +#define csio_post_event(__smp, __evt)					\
>> +	(((struct csio_sm *)(__smp))->sm_state((__smp), (uint32_t)(__evt)))
>> +
>> +#define	csio_get_state(__smp)	(((struct csio_sm *)(__smp))->sm_state)
>> +
>> +#define	csio_match_state(__smp, __state)				\
>> +	(csio_get_state((__smp)) == (csio_sm_state_t)(__state))
>> +
> 
> Why does any of the sm_state stuff need to be in macros..?  Please
> inline all of this code.

I will change them to static inline.

> 
>> +#define	CSIO_ASSERT(cond)						\
>> +do {									\
>> +	if (unlikely(!((cond))))					\
>> +		BUG();                                                  \
>> +} while (0)
>> +
>> +#ifdef __CSIO_DEBUG__
>> +#define CSIO_DB_ASSERT(__c)		CSIO_ASSERT((__c))
>> +#else
>> +#define CSIO_DB_ASSERT(__c)
>> +#endif
>> +
>> +#endif /* ifndef __CSIO_DEFS_H__ */
> 
>