devmap_dup(9e)

1devmap_dup(9E)                Driver Entry Points               devmap_dup(9E)
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NAME

6       devmap_dup - device mapping duplication entry point
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SYNOPSIS

9       #include <sys/ddi.h>
10       #include <sys/sunddi.h
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14        int prefixdevmap_dup(devmap_cookie_t dhp, void *pvtp,
15            devmap_cookie_t new_dhp, void **new_pvtp);
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INTERFACE LEVEL

19       Solaris DDI specific (Solaris DDI).
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ARGUMENTS

22       dhp          An  opaque mapping handle that the system uses to describe
23                    the mapping currently being duplicated.
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26       pvtp         Driver private mapping  data  for  the  mapping  currently
27                    being duplicated.
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30       new_dhp      An  opaque data structure that the system uses to describe
31                    the duplicated device mapping.
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34       new_pvtp     A pointer to be filled  in  by  device  drivers  with  the
35                    driver private mapping data for the duplicated device map‐
36                    ping.
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DESCRIPTION

40       The system calls devmap_dup() when a device mapping is duplicated, such
41       as during the execution of the fork(2) system call.  The system expects
42       devmap_dup() to generate new driver private data for the  new  mapping,
43       and  to  set  new_pvtp to point to it. new_dhp is the handle of the new
44       mapped object.
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47       A non-zero return value from  devmap_dup() will cause  a  corresponding
48       operation such as fork() to fail.
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RETURN VALUES

51       devmap_dup() returns the following values:
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53       0           Successful completion.
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56       Non-zero    An error occurred.
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EXAMPLES

60         static int
61         xxdevmap_dup(devmap_cookie_t dhp, void *pvtp, \
62             devmap_cookie_t new_dhp,
63             void **new_pvtp)
64         {
65             struct xxpvtdata    *prvtdata;
66             struct xxpvtdata    *p = (struct xxpvtdata *)pvtp;
67             struct xx_softc     *softc = p->softc;
68             mutex_enter(&softc->mutex);
69             /* Allocate a new private data structure */
70             prvtdata = kmem_alloc(sizeof (struct xxpvtdata), KM_SLEEP);
71             /* Return the new data */
72             prvtdata->off = p->off;
73             prvtdata->len = p->len;
74             prvtdata->ctx = p->ctx;
75             prvtdata->dhp = new_dhp;
76             prvtdata->softc = p->softc;
77             *new_pvtp = prvtdata;
78             mutex_exit(&softc->mutex);
79             return (0);
80         }
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