The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=e59b940dcb45b887974aeae8d8f86665aed2c913
commit e59b940dcb45b887974aeae8d8f86665aed2c913 Author: Konstantin Belousov <[email protected]> AuthorDate: 2022-04-20 22:14:37 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2022-04-27 23:27:34 +0000 unr(9): allow to avoid internal locking Reviewed by: markj Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D35014 --- share/man/man9/unr.9 | 5 ++++- sys/kern/subr_unit.c | 43 +++++++++++++++++++++++++++++-------------- sys/sys/systm.h | 1 + 3 files changed, 34 insertions(+), 15 deletions(-) diff --git a/share/man/man9/unr.9 b/share/man/man9/unr.9 index fe1299d40e5d..c2e9b3943829 100644 --- a/share/man/man9/unr.9 +++ b/share/man/man9/unr.9 @@ -24,7 +24,7 @@ .\" .\" $FreeBSD$ .\" -.Dd October 4, 2017 +.Dd April 21, 2022 .Dt UNR 9 .Os .Sh NAME @@ -72,6 +72,9 @@ If is not .Dv NULL , it is used for locking when allocating and freeing units. +If the passed value is the token +.Va UNR_NO_MTX , +then no locking is applied internally. Otherwise, internal mutex is used. .It Fn clear_unrhdr uh Clear all units from the specified unit number allocator entity. diff --git a/sys/kern/subr_unit.c b/sys/kern/subr_unit.c index 9ca67bcfe7a2..66314887ac39 100644 --- a/sys/kern/subr_unit.c +++ b/sys/kern/subr_unit.c @@ -312,12 +312,15 @@ clean_unrhdrl(struct unrhdr *uh) { struct unr *up; - mtx_assert(uh->mtx, MA_OWNED); + if (uh->mtx != NULL) + mtx_assert(uh->mtx, MA_OWNED); while ((up = TAILQ_FIRST(&uh->ppfree)) != NULL) { TAILQ_REMOVE(&uh->ppfree, up, list); - mtx_unlock(uh->mtx); + if (uh->mtx != NULL) + mtx_unlock(uh->mtx); Free(up); - mtx_lock(uh->mtx); + if (uh->mtx != NULL) + mtx_lock(uh->mtx); } } @@ -326,9 +329,11 @@ void clean_unrhdr(struct unrhdr *uh) { - mtx_lock(uh->mtx); + if (uh->mtx != NULL) + mtx_lock(uh->mtx); clean_unrhdrl(uh); - mtx_unlock(uh->mtx); + if (uh->mtx != NULL) + mtx_unlock(uh->mtx); } void @@ -337,7 +342,9 @@ init_unrhdr(struct unrhdr *uh, int low, int high, struct mtx *mutex) KASSERT(low >= 0 && low <= high, ("UNR: use error: new_unrhdr(%d, %d)", low, high)); - if (mutex != NULL) + if (mutex == UNR_NO_MTX) + uh->mtx = NULL; + else if (mutex != NULL) uh->mtx = mutex; else uh->mtx = &unitmtx; @@ -608,7 +615,8 @@ alloc_unrl(struct unrhdr *uh) u_int x; int y; - mtx_assert(uh->mtx, MA_OWNED); + if (uh->mtx != NULL) + mtx_assert(uh->mtx, MA_OWNED); check_unrhdr(uh, __LINE__); x = uh->low + uh->first; @@ -653,10 +661,12 @@ alloc_unr(struct unrhdr *uh) { int i; - mtx_lock(uh->mtx); + if (uh->mtx != NULL) + mtx_lock(uh->mtx); i = alloc_unrl(uh); clean_unrhdrl(uh); - mtx_unlock(uh->mtx); + if (uh->mtx != NULL) + mtx_unlock(uh->mtx); return (i); } @@ -667,7 +677,8 @@ alloc_unr_specificl(struct unrhdr *uh, u_int item, void **p1, void **p2) struct unrb *ub; u_int i, last, tl; - mtx_assert(uh->mtx, MA_OWNED); + if (uh->mtx != NULL) + mtx_assert(uh->mtx, MA_OWNED); if (item < uh->low + uh->first || item > uh->high) return (-1); @@ -773,9 +784,11 @@ alloc_unr_specific(struct unrhdr *uh, u_int item) p1 = Malloc(sizeof(struct unr)); p2 = Malloc(sizeof(struct unr)); - mtx_lock(uh->mtx); + if (uh->mtx != NULL) + mtx_lock(uh->mtx); i = alloc_unr_specificl(uh, item, &p1, &p2); - mtx_unlock(uh->mtx); + if (uh->mtx != NULL) + mtx_unlock(uh->mtx); if (p1 != NULL) Free(p1); @@ -906,10 +919,12 @@ free_unr(struct unrhdr *uh, u_int item) WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "free_unr"); p1 = Malloc(sizeof(struct unr)); p2 = Malloc(sizeof(struct unr)); - mtx_lock(uh->mtx); + if (uh->mtx != NULL) + mtx_lock(uh->mtx); free_unrl(uh, item, &p1, &p2); clean_unrhdrl(uh); - mtx_unlock(uh->mtx); + if (uh->mtx != NULL) + mtx_unlock(uh->mtx); if (p1 != NULL) Free(p1); if (p2 != NULL) diff --git a/sys/sys/systm.h b/sys/sys/systm.h index 043f347ac0d6..98637c4f4838 100644 --- a/sys/sys/systm.h +++ b/sys/sys/systm.h @@ -498,6 +498,7 @@ int root_mounted(void); * Unit number allocation API. (kern/subr_unit.c) */ struct unrhdr; +#define UNR_NO_MTX ((void *)(uintptr_t)-1) struct unrhdr *new_unrhdr(int low, int high, struct mtx *mutex); void init_unrhdr(struct unrhdr *uh, int low, int high, struct mtx *mutex); void delete_unrhdr(struct unrhdr *uh);
