Re: [PATCH 1/1] mm/block: convert rw_page users to bio op use

[Mike Christie <mchristi@redhat.com>]

On 08/04/2016 03:15 PM, Jens Axboe wrote:
> On 08/04/2016 01:59 PM, Mike Christie wrote:
>> On 08/04/2016 02:27 PM, Jens Axboe wrote:
>>> On 08/04/2016 11:50 AM, kbuild test robot wrote:
>>>> Hi Mike,
>>>>
>>>> [auto build test ERROR on linus/master]
>>>> [also build test ERROR on next-20160804]
>>>> [cannot apply to v4.7]
>>>> [if your patch is applied to the wrong git tree, please drop us a note
>>>> to help improve the system]
>>>>
>>>> url:
>>>> https://github.com/0day-ci/linux/commits/Mike-Christie/mm-block-convert-rw_page-users-to-bio-op-use/20160805-012041
>>>>
>>>>
>>>> config: i386-tinyconfig (attached as .config)
>>>> compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
>>>> reproduce:
>>>>         # save the attached .config to linux build tree
>>>>         make ARCH=i386
>>>>
>>>> All errors (new ones prefixed by >>):
>>>>
>>>>    mm/filemap.c: In function 'page_endio':
>>>>>> mm/filemap.c:892:7: error: implicit declaration of function
>>>>>> 'op_is_write' [-Werror=implicit-function-declaration]
>>>>      if (!op_is_write(op)) {
>>>>           ^~~~~~~~~~~
>>>
>>> Mike, how about moving op_is_write() outside of CONFIG_BLOCK protection
>>> in fs.h, and making the REQ_OP_* enum generally available as well? That
>>> should fix it.
>>>
>>>
>>> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
>>> index f254eb264924..14b28ff2caf8 100644
>>> --- a/include/linux/blk_types.h
>>> +++ b/include/linux/blk_types.h
>>> @@ -18,6 +18,17 @@ struct cgroup_subsys_state;
>>>  typedef void (bio_end_io_t) (struct bio *);
>>>  typedef void (bio_destructor_t) (struct bio *);
>>>
>>> +enum req_op {
>>> +    REQ_OP_READ,
>>> +    REQ_OP_WRITE,
>>> +    REQ_OP_DISCARD,        /* request to discard sectors */
>>> +    REQ_OP_SECURE_ERASE,    /* request to securely erase sectors */
>>> +    REQ_OP_WRITE_SAME,    /* write same block many times */
>>> +    REQ_OP_FLUSH,        /* request for cache flush */
>>> +};
>>> +
>>> +#define REQ_OP_BITS 3
>>> +
>>>  #ifdef CONFIG_BLOCK
>>>  /*
>>>   * main unit of I/O for the block layer and lower layers (ie drivers
>>> and
>>> @@ -228,17 +239,6 @@ enum rq_flag_bits {
>>>  #define REQ_HASHED        (1ULL << __REQ_HASHED)
>>>  #define REQ_MQ_INFLIGHT        (1ULL << __REQ_MQ_INFLIGHT)
>>>
>>> -enum req_op {
>>> -    REQ_OP_READ,
>>> -    REQ_OP_WRITE,
>>> -    REQ_OP_DISCARD,        /* request to discard sectors */
>>> -    REQ_OP_SECURE_ERASE,    /* request to securely erase sectors */
>>> -    REQ_OP_WRITE_SAME,    /* write same block many times */
>>> -    REQ_OP_FLUSH,        /* request for cache flush */
>>> -};
>>> -
>>> -#define REQ_OP_BITS 3
>>> -
>>>  typedef unsigned int blk_qc_t;
>>>  #define BLK_QC_T_NONE    -1U
>>>  #define BLK_QC_T_SHIFT    16
>>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>>> index f2a69f20926f..13cc1bfce9aa 100644
>>> --- a/include/linux/fs.h
>>> +++ b/include/linux/fs.h
>>> @@ -2465,12 +2465,13 @@ extern void init_special_inode(struct inode *,
>>> umode_t, dev_t);
>>>  extern void make_bad_inode(struct inode *);
>>>  extern bool is_bad_inode(struct inode *);
>>>
>>> -#ifdef CONFIG_BLOCK
>>>  static inline bool op_is_write(unsigned int op)
>>>  {
>>>      return op == REQ_OP_READ ? false : true;
>>>  }
>>>
>>> +#ifdef CONFIG_BLOCK
>>> +
>>>  /*
>>>   * return data direction, READ or WRITE
>>>   */
>>>
>>
>>
>> Looks ok to me. Did a quick build and test run with it.
> 
> Is anyone using the op_flags in the ->rw_page() strategy?

Not in the current code. I had just passed it in because the code was
currently passing that extra info, and I thought the original
implementer was going to use it in the future.