Extend the meaning of the CTLFLAG_TUN flag to automatically check if

there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.

Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.

MFC after:	2 weeks
Sponsored by:	Mellanox Technologies

1 files changed, 13 insertions, 19 deletions

diff --git a/sys/kern/sysv_shm.c b/sys/kern/sysv_shm.c
index 4144d94..a7a7c16 100644
--- a/sys/kern/sysv_shm.c
+++ b/sys/kern/sysv_shm.c
@@ -156,29 +156,29 @@ static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS);
 #endif
 
 struct	shminfo shminfo = {
-	SHMMAX,
-	SHMMIN,
-	SHMMNI,
-	SHMSEG,
-	SHMALL
+	.shmmax = SHMMAX,
+	.shmmin = SHMMIN,
+	.shmmni = SHMMNI,
+	.shmseg = SHMSEG,
+	.shmall = SHMALL
 };
 
 static int shm_use_phys;
 static int shm_allow_removed;
 
-SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0,
+SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RWTUN, &shminfo.shmmax, 0,
     "Maximum shared memory segment size");
-SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0,
+SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RWTUN, &shminfo.shmmin, 0,
     "Minimum shared memory segment size");
 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0,
     "Number of shared memory identifiers");
 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0,
     "Number of segments per process");
-SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0,
+SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RWTUN, &shminfo.shmall, 0,
     "Maximum number of pages available for shared memory");
-SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW,
+SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RWTUN,
     &shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core");
-SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW,
+SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RWTUN,
     &shm_allow_removed, 0,
     "Enable/Disable attachment to attached segments marked for removal");
 SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLTYPE_OPAQUE | CTLFLAG_RD,
@@ -887,20 +887,14 @@ shminit()
 	if (TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall) != 0)
 		printf("kern.ipc.shmmaxpgs is now called kern.ipc.shmall!\n");
 #endif
-	TUNABLE_ULONG_FETCH("kern.ipc.shmall", &shminfo.shmall);
-	if (!TUNABLE_ULONG_FETCH("kern.ipc.shmmax", &shminfo.shmmax)) {
+	if (shminfo.shmmax == SHMMAX) {
 		/* Initialize shmmax dealing with possible overflow. */
-		for (i = PAGE_SIZE; i > 0; i--) {
+		for (i = PAGE_SIZE; i != 0; i--) {
 			shminfo.shmmax = shminfo.shmall * i;
-			if (shminfo.shmmax >= shminfo.shmall)
+			if ((shminfo.shmmax / shminfo.shmall) == (u_long)i)
 				break;
 		}
 	}
-	TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin);
-	TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni);
-	TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg);
-	TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys);
-
 	shmalloced = shminfo.shmmni;
 	shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 	for (i = 0; i < shmalloced; i++) {