lkml.org 
[lkml]   [2015]   [Nov]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [dm-devel] [PATCH 19/32] block: add helper to get data dir from op
    From
    Date
    On 11/04/2015 04:44 PM, Bart Van Assche wrote:
    > On 11/04/2015 02:08 PM, mchristi@redhat.com wrote:
    >> From: Mike Christie <mchristi@redhat.com>
    >>
    >> In later patches the op will no longer be a bitmap, so we will
    >> not have REQ_WRITE set for all non reads like discard, flush,
    >> and write same. Drivers will still want to treat them as writes
    >> for accounting reasons, so this patch adds a helper to translate
    >> a op to a data direction.
    >>
    >> Signed-off-by: Mike Christie <mchristi@redhat.com>
    >> ---
    >> include/linux/blkdev.h | 12 ++++++++++++
    >> 1 file changed, 12 insertions(+)
    >>
    >> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
    >> index 19c2e94..cf5f518 100644
    >> --- a/include/linux/blkdev.h
    >> +++ b/include/linux/blkdev.h
    >> @@ -586,6 +586,18 @@ static inline void queue_flag_clear(unsigned int
    >> flag, struct request_queue *q)
    >>
    >> #define list_entry_rq(ptr) list_entry((ptr), struct request,
    >> queuelist)
    >>
    >> +/*
    >> + * Non REQ_OP_WRITE requests like discard, write same, etc, are
    >> + * considered WRITEs.
    >> + */
    >> +static inline int op_to_data_dir(int op)
    >> +{
    >> + if (op == REQ_OP_READ)
    >> + return READ;
    >> + else
    >> + return WRITE;
    >> +}
    >> +
    >> #define rq_data_dir(rq) ((int)((rq)->cmd_flags & 1))
    >>
    >> /*
    >>
    >
    > How about introducing two functions - op_is_write() and op_is_read() ? I
    > think that approach will result in shorter and easier to read code in
    > the contexts where these functions are used.
    >

    I can do that. You are right in how they are used. I just did the above,
    to follow the other *_data_dir calls.



    \
     
     \ /
      Last update: 2015-11-05 19:01    [W:3.254 / U:0.644 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site