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Date:      Tue, 26 Jul 2016 17:23:49 +0000 (UTC)
From:      Ed Schouten <ed@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r303340 - in head/sys: compat/freebsd32 kern sys
Message-ID:  <201607261723.u6QHNnhm080076@repo.freebsd.org>
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Author: ed
Date: Tue Jul 26 17:23:49 2016
New Revision: 303340
URL: https://svnweb.freebsd.org/changeset/base/303340

Log:
  Add shmatt_t.
  
  It looks like our "struct shmid_ds::shm_nattch" deviates from the
  standard in the sense that it is a signed integer, whereas POSIX
  requires that it is unsigned, having a special type shmatt_t.
  
  Patch up our native and 32-bit copies to use a new shmatt_t that is an
  unsigned integer. As it's unsigned, we can relax the comparisons that
  are performed on it. Leave the Linux, iBCS2, etc. copies of the
  structure alone.
  
  Reviewed by:	ngie
  Differential Revision:	https://reviews.freebsd.org/D6655

Modified:
  head/sys/compat/freebsd32/freebsd32_ipc.h
  head/sys/kern/sysv_shm.c
  head/sys/sys/shm.h

Modified: head/sys/compat/freebsd32/freebsd32_ipc.h
==============================================================================
--- head/sys/compat/freebsd32/freebsd32_ipc.h	Tue Jul 26 16:40:03 2016	(r303339)
+++ head/sys/compat/freebsd32/freebsd32_ipc.h	Tue Jul 26 17:23:49 2016	(r303340)
@@ -72,7 +72,7 @@ struct shmid_ds32 {
 	int32_t		shm_segsz;
 	pid_t		shm_lpid;
 	pid_t		shm_cpid;
-	int		shm_nattch;
+	unsigned int	shm_nattch;
 	int32_t		shm_atime;
 	int32_t		shm_dtime;
 	int32_t		shm_ctime;

Modified: head/sys/kern/sysv_shm.c
==============================================================================
--- head/sys/kern/sysv_shm.c	Tue Jul 26 16:40:03 2016	(r303339)
+++ head/sys/kern/sysv_shm.c	Tue Jul 26 17:23:49 2016	(r303340)
@@ -275,7 +275,7 @@ shm_delete_mapping(struct vmspace *vm, s
 		return (EINVAL);
 	shmmap_s->shmid = -1;
 	shmseg->u.shm_dtime = time_second;
-	if ((--shmseg->u.shm_nattch <= 0) &&
+	if (--shmseg->u.shm_nattch == 0 &&
 	    (shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) {
 		shm_deallocate_segment(shmseg);
 		shm_last_free = segnum;
@@ -289,7 +289,7 @@ shm_remove(struct shmid_kernel *shmseg, 
 
 	shmseg->u.shm_perm.key = IPC_PRIVATE;
 	shmseg->u.shm_perm.mode |= SHMSEG_REMOVED;
-	if (shmseg->u.shm_nattch <= 0) {
+	if (shmseg->u.shm_nattch == 0) {
 		shm_deallocate_segment(shmseg);
 		shm_last_free = segnum;
 	}

Modified: head/sys/sys/shm.h
==============================================================================
--- head/sys/sys/shm.h	Tue Jul 26 16:40:03 2016	(r303339)
+++ head/sys/sys/shm.h	Tue Jul 26 17:23:49 2016	(r303340)
@@ -92,12 +92,14 @@ struct shmid_ds_old {
 };
 #endif
 
+typedef unsigned int shmatt_t;
+
 struct shmid_ds {
 	struct ipc_perm shm_perm;	/* operation permission structure */
 	size_t          shm_segsz;	/* size of segment in bytes */
 	pid_t           shm_lpid;   /* process ID of last shared memory op */
 	pid_t           shm_cpid;	/* process ID of creator */
-	int		shm_nattch;	/* number of current attaches */
+	shmatt_t        shm_nattch;	/* number of current attaches */
 	time_t          shm_atime;	/* time of last shmat() */
 	time_t          shm_dtime;	/* time of last shmdt() */
 	time_t          shm_ctime;	/* time of last change by shmctl() */

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