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Date:      Tue, 09 Dec 2025 15:59:55 +0000
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Subject:   git: 305f85a3d6f2 - main - rman: Embed the mutex in struct rman instead of using a separate allocation
Message-ID:  <6938477b.350ae.527f6dd@gitrepo.freebsd.org>
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The branch main has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=305f85a3d6f2ec32ee8178413a716de7c0a73eaa

commit 305f85a3d6f2ec32ee8178413a716de7c0a73eaa
Author:     John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2025-12-09 15:59:30 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2025-12-09 15:59:30 +0000

    rman: Embed the mutex in struct rman instead of using a separate allocation
    
    This used a separate allocation when rman was first imported (back
    when the lock was a pre-SMPng "simplelock" instead of a mutex).
    
    Reported by:    des
    Reviewed by:    des
    Differential Revision:  https://reviews.freebsd.org/D54143
---
 sys/kern/subr_rman.c | 68 +++++++++++++++++++++++++---------------------------
 sys/sys/rman.h       |  3 ++-
 2 files changed, 34 insertions(+), 37 deletions(-)

diff --git a/sys/kern/subr_rman.c b/sys/kern/subr_rman.c
index b8528104ba28..e09ca10f0a2e 100644
--- a/sys/kern/subr_rman.c
+++ b/sys/kern/subr_rman.c
@@ -131,10 +131,7 @@ rman_init(struct rman *rm)
 		panic("implement RMAN_GAUGE");
 
 	TAILQ_INIT(&rm->rm_list);
-	rm->rm_mtx = malloc(sizeof *rm->rm_mtx, M_RMAN, M_NOWAIT | M_ZERO);
-	if (rm->rm_mtx == NULL)
-		return ENOMEM;
-	mtx_init(rm->rm_mtx, "rman", NULL, MTX_DEF);
+	mtx_init(&rm->rm_mtx, "rman", NULL, MTX_DEF);
 
 	mtx_lock(&rman_mtx);
 	TAILQ_INSERT_TAIL(&rman_head, rm, rm_link);
@@ -159,7 +156,7 @@ rman_manage_region(struct rman *rm, rman_res_t start, rman_res_t end)
 	r->r_end = end;
 	r->r_rm = rm;
 
-	mtx_lock(rm->rm_mtx);
+	mtx_lock(&rm->rm_mtx);
 
 	/* Skip entries before us. */
 	TAILQ_FOREACH(s, &rm->rm_list, r_link) {
@@ -216,7 +213,7 @@ rman_manage_region(struct rman *rm, rman_res_t start, rman_res_t end)
 		}
 	}
 out:
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	return rv;
 }
 
@@ -235,10 +232,10 @@ rman_fini(struct rman *rm)
 {
 	struct resource_i *r;
 
-	mtx_lock(rm->rm_mtx);
+	mtx_lock(&rm->rm_mtx);
 	TAILQ_FOREACH(r, &rm->rm_list, r_link) {
 		if (r->r_flags & RF_ALLOCATED) {
-			mtx_unlock(rm->rm_mtx);
+			mtx_unlock(&rm->rm_mtx);
 			return EBUSY;
 		}
 	}
@@ -252,12 +249,11 @@ rman_fini(struct rman *rm)
 		TAILQ_REMOVE(&rm->rm_list, r, r_link);
 		free(r, M_RMAN);
 	}
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	mtx_lock(&rman_mtx);
 	TAILQ_REMOVE(&rman_head, rm, rm_link);
 	mtx_unlock(&rman_mtx);
-	mtx_destroy(rm->rm_mtx);
-	free(rm->rm_mtx, M_RMAN);
+	mtx_destroy(&rm->rm_mtx);
 
 	return 0;
 }
@@ -267,16 +263,16 @@ rman_first_free_region(struct rman *rm, rman_res_t *start, rman_res_t *end)
 {
 	struct resource_i *r;
 
-	mtx_lock(rm->rm_mtx);
+	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);
+			mtx_unlock(&rm->rm_mtx);
 			return (0);
 		}
 	}
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	return (ENOENT);
 }
 
@@ -285,16 +281,16 @@ rman_last_free_region(struct rman *rm, rman_res_t *start, rman_res_t *end)
 {
 	struct resource_i *r;
 
-	mtx_lock(rm->rm_mtx);
+	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);
+			mtx_unlock(&rm->rm_mtx);
 			return (0);
 		}
 	}
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	return (ENOENT);
 }
 
@@ -323,7 +319,7 @@ rman_adjust_resource(struct resource *rr, rman_res_t start, rman_res_t end)
 	 * allocated resource.
 	 */
 	rm = r->r_rm;
-	mtx_lock(rm->rm_mtx);
+	mtx_lock(&rm->rm_mtx);
 #ifdef INVARIANTS
 	TAILQ_FOREACH(s, &rm->rm_list, r_link) {
 		if (s == r)
@@ -345,12 +341,12 @@ rman_adjust_resource(struct resource *rr, rman_res_t start, rman_res_t end)
 	 */
 	if (start < r->r_start && (s == NULL || (s->r_flags & RF_ALLOCATED) ||
 	    s->r_start > start)) {
-		mtx_unlock(rm->rm_mtx);
+		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);
+		mtx_unlock(&rm->rm_mtx);
 		return (EBUSY);
 	}
 
@@ -380,7 +376,7 @@ rman_adjust_resource(struct resource *rr, rman_res_t start, rman_res_t end)
 		} else
 			t->r_start = end + 1;
 	}
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 
 	/*
 	 * Handle the shrinking cases that require allocating a new
@@ -392,7 +388,7 @@ rman_adjust_resource(struct resource *rr, rman_res_t start, rman_res_t end)
 		new->r_start = r->r_start;
 		new->r_end = start - 1;
 		new->r_rm = rm;
-		mtx_lock(rm->rm_mtx);
+		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)) {
@@ -400,14 +396,14 @@ rman_adjust_resource(struct resource *rr, rman_res_t start, rman_res_t end)
 			free(new, M_RMAN);
 		} else
 			TAILQ_INSERT_BEFORE(r, new, r_link);
-		mtx_unlock(rm->rm_mtx);
+		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);
+		mtx_lock(&rm->rm_mtx);
 		r->r_end = end;
 		t = TAILQ_NEXT(r, r_link);
 		if (t != NULL && !(t->r_flags & RF_ALLOCATED)) {
@@ -415,7 +411,7 @@ rman_adjust_resource(struct resource *rr, rman_res_t start, rman_res_t end)
 			free(new, M_RMAN);
 		} else
 			TAILQ_INSERT_AFTER(&rm->rm_list, r, new, r_link);
-		mtx_unlock(rm->rm_mtx);
+		mtx_unlock(&rm->rm_mtx);
 	}
 	return (0);
 }
@@ -441,7 +437,7 @@ rman_reserve_resource(struct rman *rm, rman_res_t start, rman_res_t end,
 	    ("invalid flags %#x", flags));
 	new_rflags = (flags & ~RF_FIRSTSHARE) | RF_ALLOCATED;
 
-	mtx_lock(rm->rm_mtx);
+	mtx_lock(&rm->rm_mtx);
 
 	r = TAILQ_FIRST(&rm->rm_list);
 	if (r == NULL)
@@ -628,7 +624,7 @@ rman_reserve_resource(struct rman *rm, rman_res_t start, rman_res_t end,
 	 */
 
 out:
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	return (rv == NULL ? NULL : &rv->r_r);
 }
 
@@ -640,9 +636,9 @@ rman_activate_resource(struct resource *re)
 
 	r = re->__r_i;
 	rm = r->r_rm;
-	mtx_lock(rm->rm_mtx);
+	mtx_lock(&rm->rm_mtx);
 	r->r_flags |= RF_ACTIVE;
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	return 0;
 }
 
@@ -652,9 +648,9 @@ rman_deactivate_resource(struct resource *r)
 	struct rman *rm;
 
 	rm = r->__r_i->r_rm;
-	mtx_lock(rm->rm_mtx);
+	mtx_lock(&rm->rm_mtx);
 	r->__r_i->r_flags &= ~RF_ACTIVE;
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	return 0;
 }
 
@@ -761,9 +757,9 @@ rman_release_resource(struct resource *re)
 
 	r = re->__r_i;
 	rm = r->r_rm;
-	mtx_lock(rm->rm_mtx);
+	mtx_lock(&rm->rm_mtx);
 	rv = int_rman_release_resource(rm, r);
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	return (rv);
 }
 
@@ -991,7 +987,7 @@ sysctl_rman(SYSCTL_HANDLER_ARGS)
 	/*
 	 * Find the indexed resource and return it.
 	 */
-	mtx_lock(rm->rm_mtx);
+	mtx_lock(&rm->rm_mtx);
 	TAILQ_FOREACH(res, &rm->rm_list, r_link) {
 		if (res->r_sharehead != NULL) {
 			LIST_FOREACH(sres, res->r_sharehead, r_sharelink)
@@ -1003,7 +999,7 @@ sysctl_rman(SYSCTL_HANDLER_ARGS)
 		else if (res_idx-- == 0)
 				goto found;
 	}
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	return (ENOENT);
 
 found:
@@ -1028,7 +1024,7 @@ found:
 	ures.r_size = res->r_end - res->r_start + 1;
 	ures.r_flags = res->r_flags;
 
-	mtx_unlock(rm->rm_mtx);
+	mtx_unlock(&rm->rm_mtx);
 	error = SYSCTL_OUT(req, &ures, sizeof(ures));
 	return (error);
 }
diff --git a/sys/sys/rman.h b/sys/sys/rman.h
index 323da4a62201..2479942c3217 100644
--- a/sys/sys/rman.h
+++ b/sys/sys/rman.h
@@ -35,6 +35,7 @@
 #ifndef	_KERNEL
 #include <sys/queue.h>
 #else
+#include <sys/_mutex.h>
 #include <machine/_bus.h>
 #include <machine/resource.h>
 #endif
@@ -112,7 +113,7 @@ TAILQ_HEAD(resource_head, resource_i);
 
 struct rman {
 	struct	resource_head 	rm_list;
-	struct	mtx *rm_mtx;	/* mutex used to protect rm_list */
+	struct	mtx rm_mtx;	/* mutex used to protect rm_list */
 	TAILQ_ENTRY(rman)	rm_link; /* link in list of all rmans */
 	rman_res_t	rm_start;	/* index of globally first entry */
 	rman_res_t	rm_end;	/* index of globally last entry */

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