Use consistently "bufq_private(bufq)" instead of "bufq->bq_private"

No functional change.

Define a new module class for the bufq_strategy modules. These need to
be loaded and intialized before autoconfigure runs, since some devices
(like disks and floppy drives) want to call bufq_alloc().

Modularize the various bufq strategies

branches: 1.18.6; 1.18.10;
Mark a diagnostic only variable

branches: 1.17.2; 1.17.4;
BUFQ_PRIOCSCAN:

- to reduce cpu consumption for a long queue, maintain the sorted lists of
buffers with rbtree instead of TAILQ. i vaguely remember that the problem
pointed out by someone on a public mailing list while ago. sorry, i can't
remember who and where.

- add some #ifdef'ed out experimental code.

- bump kernel version for struct buf change.

branches: 1.16.4;
Move an assertion to the right place.

Ok: YAMAMOTO Takashi <yamt@netbsd.org>

Fixes PR #45578 (kernel crash with BUFQ_PRIOCSCAN)

branches: 1.15.2;
- don't forget to decrement burst count after reset
- signed -> unsigned where appropriate
- comments

malloc -> kmem_alloc

replace clearly broken bufq_priocscan_cancel with
something which might work. (hi reinoud)

branches: 1.12.8;
add a comment.

Add a BUFQ_CANCEL() next to BUFQ_PUT() and BUFQ_GET().

BUFQ_CANCEL(queue, element) removes the specified element previously queued
on the queue. It returns NULL if it was not found on the queue and the
element if it was successfully removed.

Run trough tech-kern and changed name from BUFQ_REVOKE() by suggestion of
Jason Thorpe.

branches: 1.10.38; 1.10.40; 1.10.42;
TRUE -> true, FALSE -> false

Replace the Mach-derived boolean_t type with the C99 bool type. A
future commit will replace use of TRUE and FALSE with true and false.

branches: 1.8.12;
use consistent order of function specifiers and type specifiers.
(int inline -> inline int)

branches: 1.7.4; 1.7.6; 1.7.8; 1.7.12; 1.7.14;
Remove leading __ from __(const|inline|signed|volatile) -- it is obsolete.

merge ktrace-lwp.

- change the way to specify a bufq strategy. (by string rather than by number)
- rather than embedding bufq_state in driver softc,
have a pointer to the former.
- move bufq related functions from kern/subr_disk.c to kern/subr_bufq.c.
- rename method to strategy for consistency.
- move some definitions which don't need to be exposed to the rest of kernel
from sys/bufq.h to sys/bufq_impl.h.
(is it better to move it to kern/ or somewhere?)
- fix some obvious breakage in dev/qbus/ts.c. (not tested)

branches: 1.4.4;
bufq_priocscan_get: don't update state in the case of !remove. fix BUFQ_PEEK.

branches: 1.3.4; 1.3.6;
lookup bufq using link_set rather than a switch statement.

move buffer queue related stuffs from buf.h to their own header, bufq.h.

branches: 1.1.2;
move i/o schedulers to their own files.
namely, from kern/subr_disk.c to kern/bufq_{fcfs,disksort,readprio,priocscan}.c.

Define a new module class for the bufq_strategy modules. These need to
be loaded and intialized before autoconfigure runs, since some devices
(like disks and floppy drives) want to call bufq_alloc().

Modularize the various bufq strategies

branches: 1.18.6;
Mark a diagnostic only variable

branches: 1.17.2; 1.17.4;
BUFQ_PRIOCSCAN:

- to reduce cpu consumption for a long queue, maintain the sorted lists of
buffers with rbtree instead of TAILQ. i vaguely remember that the problem
pointed out by someone on a public mailing list while ago. sorry, i can't
remember who and where.

- add some #ifdef'ed out experimental code.

- bump kernel version for struct buf change.

branches: 1.16.4;
Move an assertion to the right place.

Ok: YAMAMOTO Takashi <yamt@netbsd.org>

Fixes PR #45578 (kernel crash with BUFQ_PRIOCSCAN)

branches: 1.15.2;
- don't forget to decrement burst count after reset
- signed -> unsigned where appropriate
- comments

malloc -> kmem_alloc

replace clearly broken bufq_priocscan_cancel with
something which might work. (hi reinoud)

branches: 1.12.8;
add a comment.

Add a BUFQ_CANCEL() next to BUFQ_PUT() and BUFQ_GET().

BUFQ_CANCEL(queue, element) removes the specified element previously queued
on the queue. It returns NULL if it was not found on the queue and the
element if it was successfully removed.

Run trough tech-kern and changed name from BUFQ_REVOKE() by suggestion of
Jason Thorpe.

branches: 1.10.38; 1.10.40; 1.10.42;
TRUE -> true, FALSE -> false

Replace the Mach-derived boolean_t type with the C99 bool type. A
future commit will replace use of TRUE and FALSE with true and false.

branches: 1.8.12;
use consistent order of function specifiers and type specifiers.
(int inline -> inline int)

branches: 1.7.4; 1.7.6; 1.7.8; 1.7.12; 1.7.14;
Remove leading __ from __(const|inline|signed|volatile) -- it is obsolete.

merge ktrace-lwp.

- change the way to specify a bufq strategy. (by string rather than by number)
- rather than embedding bufq_state in driver softc,
have a pointer to the former.
- move bufq related functions from kern/subr_disk.c to kern/subr_bufq.c.
- rename method to strategy for consistency.
- move some definitions which don't need to be exposed to the rest of kernel
from sys/bufq.h to sys/bufq_impl.h.
(is it better to move it to kern/ or somewhere?)
- fix some obvious breakage in dev/qbus/ts.c. (not tested)

branches: 1.4.4;
bufq_priocscan_get: don't update state in the case of !remove. fix BUFQ_PEEK.

branches: 1.3.4; 1.3.6;
lookup bufq using link_set rather than a switch statement.

move buffer queue related stuffs from buf.h to their own header, bufq.h.

branches: 1.1.2;
move i/o schedulers to their own files.
namely, from kern/subr_disk.c to kern/bufq_{fcfs,disksort,readprio,priocscan}.c.