git: a10870ecea81 - main - posix shm: mark backing objects with SHM_POSIXSHM flag

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=a10870ecea813042db7c41e906e1a5c5693f8a34

commit a10870ecea813042db7c41e906e1a5c5693f8a34
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2024-10-07 01:26:38 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2024-10-08 12:37:57 +0000

    posix shm: mark backing objects with SHM_POSIXSHM flag
    
    and consistently store the pointer to shmfd into pager priv data space.
    
    Reviewed by:    markj
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D46970
---
 sys/kern/uipc_shm.c | 16 +++++++++++-----
 sys/vm/vm_object.h  |  2 ++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c
index a5b2e62c568e..cf98e1410074 100644
--- a/sys/kern/uipc_shm.c
+++ b/sys/kern/uipc_shm.c
@@ -945,15 +945,20 @@ shm_alloc(struct ucred *ucred, mode_t mode, bool largepage)
 	shmfd->shm_gid = ucred->cr_gid;
 	shmfd->shm_mode = mode;
 	if (largepage) {
-		shmfd->shm_object = phys_pager_allocate(NULL,
+		obj = shmfd->shm_object = phys_pager_allocate(NULL,
 		    &shm_largepage_phys_ops, NULL, shmfd->shm_size,
 		    VM_PROT_DEFAULT, 0, ucred);
+		VM_OBJECT_WLOCK(shmfd->shm_object);
+		obj->un_pager.phys.phys_priv = shmfd;
+		vm_object_set_flag(obj, OBJ_POSIXSHM);
+		VM_OBJECT_WUNLOCK(shmfd->shm_object);
 		shmfd->shm_lp_alloc_policy = SHM_LARGEPAGE_ALLOC_DEFAULT;
 	} else {
 		obj = vm_pager_allocate(shmfd_pager_type, NULL,
 		    shmfd->shm_size, VM_PROT_DEFAULT, 0, ucred);
 		VM_OBJECT_WLOCK(obj);
 		obj->un_pager.swp.swp_priv = shmfd;
+		vm_object_set_flag(obj, OBJ_POSIXSHM);
 		VM_OBJECT_WUNLOCK(obj);
 		shmfd->shm_object = obj;
 	}
@@ -993,11 +998,12 @@ shm_drop(struct shmfd *shmfd)
 		rangelock_destroy(&shmfd->shm_rl);
 		mtx_destroy(&shmfd->shm_mtx);
 		obj = shmfd->shm_object;
-		if (!shm_largepage(shmfd)) {
-			VM_OBJECT_WLOCK(obj);
+		VM_OBJECT_WLOCK(obj);
+		if (shm_largepage(shmfd))
+			obj->un_pager.phys.phys_priv = NULL;
+		else
 			obj->un_pager.swp.swp_priv = NULL;
-			VM_OBJECT_WUNLOCK(obj);
-		}
+		VM_OBJECT_WUNLOCK(obj);
 		vm_object_deallocate(obj);
 		free(shmfd, M_SHMFD);
 	}
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
index 73284fddd2a6..c7f0dd0943ba 100644
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -172,6 +172,7 @@ struct vm_object {
 				void *data_ptr;
 				uintptr_t data_val;
 			};
+			void *phys_priv;
 		} phys;
 	} un_pager;
 	struct ucred *cred;
@@ -202,6 +203,7 @@ struct vm_object {
 #define	OBJ_PAGERPRIV1	0x00004000	/* Pager private */
 #define	OBJ_PAGERPRIV2	0x00008000	/* Pager private */
 #define	OBJ_SYSVSHM	0x00010000	/* SysV SHM */
+#define	OBJ_POSIXSHM	0x00020000	/* Posix SHM */
 
 /*
  * Helpers to perform conversion between vm_object page indexes and offsets.