MFC r322258, r324941, r324956, r325018

r322258:
Make p1003_1b.aio_listio_max a tunable

p1003_1b.aio_listio_max is now a tunable. Its value is reflected in the
sysctl of the same name, and the sysconf(3) variable _SC_AIO_LISTIO_MAX.
Its value will be bounded from below by the compile-time constant
AIO_LISTIO_MAX and from above by the compile-time constant
MAX_AIO_QUEUE_PER_PROC and the tunable vfs.aio.max_aio_queue.

Reviewed by:	jhb, kib
Relnotes:	yes
Sponsored by:	Spectra Logic Corp
Differential Revision:	https://reviews.freebsd.org/D11601

r324941:
Remove artificial restriction on lio_listio's operation count

In r322258 I made p1003_1b.aio_listio_max a tunable. However, further
investigation shows that there was never any good reason for that limit to
exist in the first place. It's used in two completely different ways:

* To size a UMA zone, which globally limits the number of concurrent
  aio_suspend calls.

* To artifically limit the number of operations in a single lio_listio call.
  There doesn't seem to be any memory allocation associated with this limit.

This change does two things:

* Properly names aio_suspend's UMA zone, and sizes it based on a new constant.

* Eliminates the artifical restriction on lio_listio. Instead, lio_listio
  calls will now be limited by the more generous max_aio_queue_per_proc. The
  old p1003_1b.aio_listio_max is now an alias for
  vfs.aio.max_aio_queue_per_proc, so sysconf(3) will still work with
  _SC_AIO_LISTIO_MAX.

Reported by:	bde
Reviewed by:	jhb
Sponsored by:	Spectra Logic Corp
Differential Revision:	https://reviews.freebsd.org/D12120

r324956:
Bump man page revision dates for r324941

Reported by:	jhb
X-MFC-with:	324941
Sponsored by:	Spectra Logic Corp

r325018:
Fix aio_suspend in 32-bit emulation

An off-by-one error has been present since the system call was first present
in 185878.  It additionally became a memory corruption bug after change
324941.  The failure is actually revealed by our existing AIO tests.
However, apparently nobody's been running those in 32-bit emulation mode.

Reported by:	Coverity, cem
CID:		1382114
X-MFC-With:	324941
Sponsored by:	Spectra Logic Corp

2 files changed, 8 insertions, 8 deletions

diff --git a/lib/libc/sys/aio_suspend.2 b/lib/libc/sys/aio_suspend.2
index 0ff25f5..be6d7e1 100644
--- a/lib/libc/sys/aio_suspend.2
+++ b/lib/libc/sys/aio_suspend.2
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 2, 1999
+.Dd Oct 23, 2017
 .Dt AIO_SUSPEND 2
 .Os
 .Sh NAME
@@ -85,10 +85,10 @@ expired before any I/O requests completed.
 The
 .Fa iocbs
 argument
-contains more than
-.Dv AIO_LISTIO_MAX
-asynchronous I/O requests, or at least one of the requests is not
-valid.
+contains more asynchronous I/O requests than the
+.Va vfs.aio.max_aio_queue_per_proc
+.Xr sysctl 8
+variable, or at least one of the requests is not valid.
 .It Bq Er EINTR
 the suspend was interrupted by a signal.
 .El
diff --git a/lib/libc/sys/lio_listio.2 b/lib/libc/sys/lio_listio.2
index ae228f7..abc9f0c 100644
--- a/lib/libc/sys/lio_listio.2
+++ b/lib/libc/sys/lio_listio.2
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 15, 2016
+.Dd Oct 23, 2017
 .Dt LIO_LISTIO 2
 .Os
 .Sh NAME
@@ -161,7 +161,7 @@ function will fail if:
 There are not enough resources to enqueue the requests.
 .It Bq Er EAGAIN
 The request would cause the system-wide limit
-.Dv AIO_MAX
+.Dv {AIO_MAX}
 to be exceeded.
 .It Bq Er EINVAL
 The
@@ -173,7 +173,7 @@ nor
 or
 .Fa nent
 is greater than
-.Dv AIO_LISTIO_MAX .
+.Dv {AIO_LISTIO_MAX} .
 .It Bq Er EINVAL
 The asynchronous notification method in
 .Fa sig->sigev_notify