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Extend the rman(9) API to support altering an existing resource.

Browse Source 
Specifically, these changes allow a resource to back a relocatable and
resizable resource such as the I/O window decoders in PCI-PCI bridges.
- rman_adjust_resource() can adjust the start and end address of an
  existing resource.  It only succeeds if the newly requested address
  space is already free.  It also supports shrinking a resource in
  which case the freed space will be marked unallocated in the rman.
- rman_first_free_region() and rman_last_free_region() return the
  start and end addresses for the first or last unallocated region in
  an rman, respectively.  This can be used to determine by how much
  the resource backing an rman must be adjusted to accomodate an
  allocation request that does not fit into the existing rman.

While here, document the rm_start and rm_end fields in struct rman,
rman_is_region_manager(), the bound argument to
rman_reserve_resource_bound(), and rman_init_from_resource().
This commit is contained in:
John Baldwin 2011-04-29 20:05:19 +00:00
parent b67d11bbcc
commit bb82622c3e
4 changed files with 288 additions and 5 deletions
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5
share/man/man9/Makefile
View File

@ -967,9 +967,11 @@ MLINKS+=refcount.9 refcount_acquire.9 \
MLINKS+=resource_int_value.9 resource_long_value.9 \
resource_int_value.9 resource_string_value.9
MLINKS+=rman.9 rman_activate_resource.9 \
rman.9 rman_adjust_resource.9 \
rman.9 rman_await_resource.9 \
rman.9 rman_deactivate_resource.9 \
rman.9 rman_fini.9 \
rman.9 rman_first_free_region.9 \
rman.9 rman_get_bushandle.9 \
rman.9 rman_get_bustag.9 \
rman.9 rman_get_device.9 \
@ -980,6 +982,9 @@ MLINKS+=rman.9 rman_activate_resource.9 \
rman.9 rman_get_start.9 \
rman.9 rman_get_virtual.9 \
rman.9 rman_init.9 \
rman.9 rman_init_from_resource.9 \
rman.9 rman_is_region_manager.9 \
rman.9 rman_last_free_region.9 \
rman.9 rman_make_alignment_flags.9 \
rman.9 rman_manage_region.9 \
rman.9 rman_release_resource.9 \

127
share/man/man9/rman.9
View File

@ -25,17 +25,22 @@
.\"
.\" $FreeBSD$
.\"
.Dd April 29, 2007
.Dd April 29, 2011
.Dt RMAN 9
.Os
.Sh NAME
.Nm rman ,
.Nm rman_activate_resource ,
.Nm rman_adjust_resource ,
.Nm rman_await_resource ,
.Nm rman_deactivate_resource ,
.Nm rman_fini ,
.Nm rman_init ,
.Nm rman_init_from_resource ,
.Nm rman_is_region_manager ,
.Nm rman_manage_region ,
.Nm rman_first_free_region ,
.Nm rman_last_free_region ,
.Nm rman_release_resource ,
.Nm rman_reserve_resource ,
.Nm rman_reserve_resource_bound ,
@ -60,6 +65,8 @@
.Ft int
.Fn rman_activate_resource "struct resource *r"
.Ft int
.Fn rman_adjust_resource "struct resource *r" "u_long start" "u_long end"
.Ft int
.Fn rman_await_resource "struct resource *r" "int pri2" "int timo"
.Ft int
.Fn rman_deactivate_resource "struct resource *r"
@ -68,8 +75,16 @@
.Ft int
.Fn rman_init "struct rman *rm"
.Ft int
.Fn rman_init_from_resource "struct rman *rm" "struct resource *r"
.Ft int
.Fn rman_is_region_manager "struct resource *r" "struct rman *rm"
.Ft int
.Fn rman_manage_region "struct rman *rm" "u_long start" "u_long end"
.Ft int
.Fn rman_first_free_region "struct rman *rm" "u_long *start" "u_long *end"
.Ft int
.Fn rman_last_free_region "struct rman *rm" "u_long *start" "u_long *end"
.Ft int
.Fn rman_release_resource "struct resource *r"
.Ft "struct resource *"
.Fo rman_reserve_resource
@ -155,6 +170,14 @@ shall be set to
The field
.Va rm_descr
shall be set to a string that describes the resource to be managed.
The
.Va rm_start
and
.Va rm_end
fields may be set to limit the range of acceptable resource addresses.
If these fields are not set,
.Fn rman_init
will initialize them to allow the entire range of resource addresses.
It also initializes any mutexes associated with the structure.
If
.Fn rman_init
@ -194,12 +217,49 @@ If successful,
will return 0.
If the region overlaps with an existing region, it will return
.Er EBUSY .
If any part of the region falls outside of the valid address range for
.Fa rm ,
it will return
.Er EINVAL .
.Er ENOMEM
will be return when
will be returned when
.Fn rman_manage_region
failed to allocate memory for the region.
.Pp
The
.Fn rman_init_from_resource
function is a wrapper routine to create a resource manager backed by an
existing resource.
It initializes
.Fa rm
using
.Fn rman_init
and then adds a region to
.Fa rm
corresponding to the address range allocated to
.Fa r
via
.Fn rman_manage_region .
.Pp
The
.Fn rman_first_free_region
and
.Fn rman_last_free_region
functions can be used to query a resource manager for its first
.Pq or last
unallocated region.
If
.Fa rm
contains no free region,
these functions will return
.Er ENOENT .
Otherwise,
.Fa *start
and
.Fa *end
are set to the bounds of the free region and zero is returned.
.Pp
The
.Fn rman_reserve_resource_bound
function is where the bulk of the
.Nm
@ -212,8 +272,9 @@ The caller can specify the
.Fa start
and
.Fa end
of an acceptable range, as well as
alignment, and the code will attempt to find a free segment which fits.
of an acceptable range,
as well as a boundary restriction and required aligment,
and the code will attempt to find a free segment which fits.
The
.Fa start
argument is the lowest acceptable starting value of the resource.
@ -225,6 +286,19 @@ Therefore,
must be \[<=]
.Fa end
for any allocation to happen.
The aligment requirement
.Pq if any
is specified in
.Fa flags .
The
.Fa bound
argument may be set to specify a boundary restriction such that an
allocated region may cross an address that is a multiple of the
boundary.
The
.Fa bound
argument must be a power of two.
It may be set to zero to specify no boundary restriction.
The default behavior is to allocate an exclusive segment, unless the
.Dv RF_SHAREABLE
or
@ -240,7 +314,7 @@ function is used to reserve resources within a previously established region.
It is a simplified interface to
.Fn rman_reserve_resource_bound
which passes 0 for the
.Fa flags
.Fa bound
argument.
.Pp
The
@ -251,6 +325,49 @@ This should be used when calling
.Fn rman_reserve_resource_bound .
.Pp
The
.Fn rman_is_region_manager
function returns true if the allocated resource
.Fa r
was allocated from
.Fa rm .
Otherwise,
it returns false.
.Pp
The
.Fn rman_adjust_resource
function is used to adjust the reserved address range of an allocated resource
to reserve
.Fa start
through
.Fa end .
It can be used to grow or shrink one or both ends of the resource range.
The current implementation does not support entirely relocating the resource
and will fail with
.Er EINVAL
if the new resource range does not overlap the old resource range.
If either end of the resource range grows and the new resource range would
conflict with another allocated resource,
the function will fail with
.Er EBUSY .
The
.Fn rman_adjust_resource
function does not support adjusting the resource range for shared resources
and will fail such attempts with
.Er EINVAL .
Upon success,
the resource
.Fa r
will have a start address of
.Fa start
and an end address of
.Fa end
and the function will return zero.
Note that none of the constraints of the original allocation request such
as alignment or boundary restrictions are checked by
.Fn rman_adjust_resource .
It is the caller's responsibility to enforce any such requirements.
.Pp
The
.Fn rman_release_resource
function releases the reserved resource
.Fa r .

158
sys/kern/subr_rman.c
View File

@ -272,6 +272,164 @@ rman_fini(struct rman *rm)
return 0;
}
int
rman_first_free_region(struct rman *rm, u_long *start, u_long *end)
{
struct resource_i *r;
mtx_lock(rm->rm_mtx);
TAILQ_FOREACH(r, &rm->rm_list, r_link) {
if (!(r->r_flags & RF_ALLOCATED)) {
*start = r->r_start;
*end = r->r_end;
mtx_unlock(rm->rm_mtx);
return (0);
}
}
mtx_unlock(rm->rm_mtx);
return (ENOENT);
}
int
rman_last_free_region(struct rman *rm, u_long *start, u_long *end)
{
struct resource_i *r;
mtx_lock(rm->rm_mtx);
TAILQ_FOREACH_REVERSE(r, &rm->rm_list, resource_head, r_link) {
if (!(r->r_flags & RF_ALLOCATED)) {
*start = r->r_start;
*end = r->r_end;
mtx_unlock(rm->rm_mtx);
return (0);
}
}
mtx_unlock(rm->rm_mtx);
return (ENOENT);
}
/* Shrink or extend one or both ends of an allocated resource. */
int
rman_adjust_resource(struct resource *rr, u_long start, u_long end)
{
struct resource_i *r, *s, *t, *new;
struct rman *rm;
/* Not supported for shared resources. */
r = rr->__r_i;
if (r->r_flags & (RF_TIMESHARE | RF_SHAREABLE))
return (EINVAL);
/*
* This does not support wholesale moving of a resource. At
* least part of the desired new range must overlap with the
* existing resource.
*/
if (end < r->r_start || r->r_end < start)
return (EINVAL);
/*
* Find the two resource regions immediately adjacent to the
* allocated resource.
*/
rm = r->r_rm;
mtx_lock(rm->rm_mtx);
#ifdef INVARIANTS
TAILQ_FOREACH(s, &rm->rm_list, r_link) {
if (s == r)
break;
}
if (s == NULL)
panic("resource not in list");
#endif
s = TAILQ_PREV(r, resource_head, r_link);
t = TAILQ_NEXT(r, r_link);
KASSERT(s == NULL || s->r_end + 1 == r->r_start,
("prev resource mismatch"));
KASSERT(t == NULL || r->r_end + 1 == t->r_start,
("next resource mismatch"));
/*
* See if the changes are permitted. Shrinking is always allowed,
* but growing requires sufficient room in the adjacent region.
*/
if (start < r->r_start && (s == NULL || (s->r_flags & RF_ALLOCATED) ||
s->r_start > start)) {
mtx_unlock(rm->rm_mtx);
return (EBUSY);
}
if (end > r->r_end && (t == NULL || (t->r_flags & RF_ALLOCATED) ||
t->r_end < end)) {
mtx_unlock(rm->rm_mtx);
return (EBUSY);
}
/*
* While holding the lock, grow either end of the resource as
* needed and shrink either end if the shrinking does not require
* allocating a new resource. We can safely drop the lock and then
* insert a new range to handle the shrinking case afterwards.
*/
if (start < r->r_start ||
(start > r->r_start && s != NULL && !(s->r_flags & RF_ALLOCATED))) {
KASSERT(s->r_flags == 0, ("prev is busy"));
r->r_start = start;
if (s->r_start == start) {
TAILQ_REMOVE(&rm->rm_list, s, r_link);
free(s, M_RMAN);
} else
s->r_end = start - 1;
}
if (end > r->r_end ||
(end < r->r_end && t != NULL && !(t->r_flags & RF_ALLOCATED))) {
KASSERT(t->r_flags == 0, ("next is busy"));
r->r_end = end;
if (t->r_end == end) {
TAILQ_REMOVE(&rm->rm_list, t, r_link);
free(t, M_RMAN);
} else
t->r_start = end + 1;
}
mtx_unlock(rm->rm_mtx);
/*
* Handle the shrinking cases that require allocating a new
* resource to hold the newly-free region. We have to recheck
* if we still need this new region after acquiring the lock.
*/
if (start > r->r_start) {
new = int_alloc_resource(M_WAITOK);
new->r_start = r->r_start;
new->r_end = start - 1;
new->r_rm = rm;
mtx_lock(rm->rm_mtx);
r->r_start = start;
s = TAILQ_PREV(r, resource_head, r_link);
if (s != NULL && !(s->r_flags & RF_ALLOCATED)) {
s->r_end = start - 1;
free(new, M_RMAN);
} else
TAILQ_INSERT_BEFORE(r, new, r_link);
mtx_unlock(rm->rm_mtx);
}
if (end < r->r_end) {
new = int_alloc_resource(M_WAITOK);
new->r_start = end + 1;
new->r_end = r->r_end;
new->r_rm = rm;
mtx_lock(rm->rm_mtx);
r->r_end = end;
t = TAILQ_NEXT(r, r_link);
if (t != NULL && !(t->r_flags & RF_ALLOCATED)) {
t->r_start = end + 1;
free(new, M_RMAN);
} else
TAILQ_INSERT_AFTER(&rm->rm_list, r, new, r_link);
mtx_unlock(rm->rm_mtx);
}
return (0);
}
struct resource *
rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
u_long count, u_long bound, u_int flags,

3
sys/sys/rman.h
View File

@ -116,7 +116,9 @@ struct rman {
TAILQ_HEAD(rman_head, rman);
int rman_activate_resource(struct resource *r);
int rman_adjust_resource(struct resource *r, u_long start, u_long end);
int rman_await_resource(struct resource *r, int pri, int timo);
int rman_first_free_region(struct rman *rm, u_long *start, u_long *end);
bus_space_handle_t rman_get_bushandle(struct resource *);
bus_space_tag_t rman_get_bustag(struct resource *);
u_long rman_get_end(struct resource *);
@ -130,6 +132,7 @@ int rman_deactivate_resource(struct resource *r);
int rman_fini(struct rman *rm);
int rman_init(struct rman *rm);
int rman_init_from_resource(struct rman *rm, struct resource *r);
int rman_last_free_region(struct rman *rm, u_long *start, u_long *end);
uint32_t rman_make_alignment_flags(uint32_t size);
int rman_manage_region(struct rman *rm, u_long start, u_long end);
int rman_is_region_manager(struct resource *r, struct rman *rm);