minphys(9f) 맨 페이지 - 윈디하나의 솔라나라

개요

섹션
맨 페이지 이름
검색(S)

minphys(9f)

physio(9F)                     Kernel Functions                     physio(9F)



NAME
       physio, minphys - perform physical I/O

SYNOPSIS
       #include <sys/types.h>
       #include <sys/buf.h>
       #include <sys/uio.h>

       int physio(int(*strat)(struct buf *), struct buf *bp, dev_t dev,
            int rw, void (*mincnt)(struct buf *), struct uio *uio);


       void minphys(struct buf *bp);

INTERFACE LEVEL
       Solaris DDI specific (Solaris DDI).

PARAMETERS
   physio()
       strat     Pointer to device strategy routine.


       bp        Pointer to a buf(9S) structure describing the transfer. If bp
                 is set to NULL then physio() allocates one which is automati‐
                 cally released upon completion.


       dev       The device number.


       rw        Read/write  flag. This is either B_READ when reading from the
                 device, or B_WRITE when writing to the device.


       mincnt    Routine which bounds the maximum transfer unit size.


       uio       Pointer to the uio structure which  describes  the  user  I/O
                 request.


   minphys()
       bp    Pointer to a buf structure.


DESCRIPTION
       physio()  performs unbuffered I/O operations between the device dev and
       the address space described in the uio structure.


       Prior to the start of the  transfer  physio()  verifies  the  requested
       operation  is  valid  by  checking  the protection of the address space
       specified in the uio structure. It then locks the pages involved in the
       I/O transfer so they can not be paged out. The device strategy routine,
       strat(), is then called one or more times to perform the  physical  I/O
       operations.  physio()  uses biowait(9F) to block until strat() has com‐
       pleted each transfer.  Upon  completion,  or  detection  of  an  error,
       physio() unlocks the pages and returns the error status.


       physio()  uses  mincnt() to bound the maximum transfer unit size to the
       system, or device, maximum length. minphys()  is  the  system  mincnt()
       routine  for use with physio() operations. Drivers which do not provide
       their own local mincnt() routines should call physio() with minphys().


       minphys() limits the value of bp->b_bcount to a  sensible  default  for
       the capabilities of the system. Drivers that provide their own mincnt()
       routine should also call minphys() to make sure they do not exceed  the
       system limit.

RETURN VALUES
       physio() returns:

       0           Upon success.


       non-zero    Upon failure.


CONTEXT
       physio() can be called from user context only.

SEE ALSO
       strategy(9E), biodone(9F), biowait(9F), buf(9S), uio(9S)


       Writing Device Drivers in Oracle Solaris 11.4

WARNINGS
       Since physio() calls biowait() to block until each buf transfer is com‐
       plete, it is the drivers responsibility to call  biodone(9F)  when  the
       transfer is complete, or physio() will block forever.



Oracle Solaris 11.4               2 Apr 1993                        physio(9F)
맨 페이지 내용의 저작권은 맨 페이지 작성자에게 있습니다.
RSS ATOM XHTML 5 CSS3