From f832287e48b0c3200a0ca46c5b85f9b98f5a095e Mon Sep 17 00:00:00 2001
From: Matthew Dillon <dillon@dragonflybsd.org>
Date: Sat, 27 May 2006 20:17:17 +0000
Subject: [PATCH] Mark various forms of read() and write() MPSAFE.  Note that
 the MP lock is still acquire, but now its a lot deeper in the fileops.

Mark dup(), dup2(), close(), closefrom(), and fcntl() MPSAFE.  Some code
paths don't have to get the MP lock, but most still do deeper into the
fileops.
---
 sys/kern/init_sysent.c   | 28 ++++++++++++++--------------
 sys/kern/kern_subr.c     |  4 +++-
 sys/kern/sys_generic.c   | 38 ++++++++++++++++++++++++++++++++++++--
 sys/kern/syscalls.c      |  2 +-
 sys/kern/syscalls.master | 28 ++++++++++++++--------------
 sys/kern/vfs_bio.c       | 35 ++++++++++++++++++++++++++---------
 sys/kern/vfs_lock.c      |  2 +-
 sys/sys/syscall-args     |  4 ++--
 sys/sys/syscall-hide.h   |  4 ++--
 sys/sys/syscall.h        |  4 ++--
 sys/sys/syscall.mk       |  4 ++--
 sys/sys/sysproto.h       |  4 ++--
 sys/sys/sysunion.h       |  4 ++--
 sys/sys/uio.h            |  5 ++++-
 14 files changed, 111 insertions(+), 55 deletions(-)

diff --git a/sys/kern/init_sysent.c b/sys/kern/init_sysent.c
index 4269c9a4af..3002b5d171 100644
--- a/sys/kern/init_sysent.c
+++ b/sys/kern/init_sysent.c
@@ -2,7 +2,7 @@
  * System call switch table.
  *
  * DO NOT EDIT-- this file is automatically generated.
- * $DragonFly: src/sys/kern/init_sysent.c,v 1.36 2006/05/24 12:42:01 corecode Exp $
+ * $DragonFly: src/sys/kern/init_sysent.c,v 1.37 2006/05/27 20:17:16 dillon Exp $
  * created from DragonFly: src/sys/kern/syscalls.master,v 1.35 2006/05/24 12:40:19 corecode Exp 
  */
 
@@ -37,10 +37,10 @@ struct sysent sysent[] = {
 	{ 0, (sy_call_t *)nosys },			/* 0 = syscall */
 	{ AS(sys_exit_args), (sy_call_t *)sys_exit },	/* 1 = exit */
 	{ 0, (sy_call_t *)fork },			/* 2 = fork */
-	{ AS(read_args), (sy_call_t *)read },		/* 3 = read */
-	{ AS(write_args), (sy_call_t *)write },		/* 4 = write */
+	{ SYF_MPSAFE | AS(read_args), (sy_call_t *)read },	/* 3 = read */
+	{ SYF_MPSAFE | AS(write_args), (sy_call_t *)write },	/* 4 = write */
 	{ AS(open_args), (sy_call_t *)open },		/* 5 = open */
-	{ AS(close_args), (sy_call_t *)close },		/* 6 = close */
+	{ SYF_MPSAFE | AS(close_args), (sy_call_t *)close },	/* 6 = close */
 	{ AS(wait_args), (sy_call_t *)wait4 },		/* 7 = wait4 */
 	{ compat(AS(ocreat_args),creat) },		/* 8 = old creat */
 	{ AS(link_args), (sy_call_t *)link },		/* 9 = link */
@@ -75,7 +75,7 @@ struct sysent sysent[] = {
 	{ compat(AS(ostat_args),stat) },		/* 38 = old stat */
 	{ 0, (sy_call_t *)getppid },			/* 39 = getppid */
 	{ compat(AS(olstat_args),lstat) },		/* 40 = old lstat */
-	{ AS(dup_args), (sy_call_t *)dup },		/* 41 = dup */
+	{ SYF_MPSAFE | AS(dup_args), (sy_call_t *)dup },	/* 41 = dup */
 	{ 0, (sy_call_t *)pipe },			/* 42 = pipe */
 	{ 0, (sy_call_t *)getegid },			/* 43 = getegid */
 	{ AS(profil_args), (sy_call_t *)profil },	/* 44 = profil */
@@ -124,9 +124,9 @@ struct sysent sysent[] = {
 	{ compat(AS(gethostname_args),gethostname) },	/* 87 = old gethostname */
 	{ compat(AS(sethostname_args),sethostname) },	/* 88 = old sethostname */
 	{ SYF_MPSAFE | 0, (sy_call_t *)getdtablesize },	/* 89 = getdtablesize */
-	{ AS(dup2_args), (sy_call_t *)dup2 },		/* 90 = dup2 */
+	{ SYF_MPSAFE | AS(dup2_args), (sy_call_t *)dup2 },	/* 90 = dup2 */
 	{ 0, (sy_call_t *)nosys },			/* 91 = getdopt */
-	{ AS(fcntl_args), (sy_call_t *)fcntl },		/* 92 = fcntl */
+	{ SYF_MPSAFE | AS(fcntl_args), (sy_call_t *)fcntl },	/* 92 = fcntl */
 	{ AS(select_args), (sy_call_t *)select },	/* 93 = select */
 	{ 0, (sy_call_t *)nosys },			/* 94 = setdopt */
 	{ AS(fsync_args), (sy_call_t *)fsync },		/* 95 = fsync */
@@ -154,8 +154,8 @@ struct sysent sysent[] = {
 	{ AS(getrusage_args), (sy_call_t *)getrusage },	/* 117 = getrusage */
 	{ AS(getsockopt_args), (sy_call_t *)getsockopt },	/* 118 = getsockopt */
 	{ 0, (sy_call_t *)nosys },			/* 119 = resuba */
-	{ AS(readv_args), (sy_call_t *)readv },		/* 120 = readv */
-	{ AS(writev_args), (sy_call_t *)writev },	/* 121 = writev */
+	{ SYF_MPSAFE | AS(readv_args), (sy_call_t *)readv },	/* 120 = readv */
+	{ SYF_MPSAFE | AS(writev_args), (sy_call_t *)writev },	/* 121 = writev */
 	{ AS(settimeofday_args), (sy_call_t *)settimeofday },	/* 122 = settimeofday */
 	{ AS(fchown_args), (sy_call_t *)fchown },	/* 123 = fchown */
 	{ AS(fchmod_args), (sy_call_t *)fchmod },	/* 124 = fchmod */
@@ -207,8 +207,8 @@ struct sysent sysent[] = {
 	{ AS(msgsys_args), (sy_call_t *)msgsys },	/* 170 = msgsys */
 	{ AS(shmsys_args), (sy_call_t *)shmsys },	/* 171 = shmsys */
 	{ 0, (sy_call_t *)nosys },			/* 172 = nosys */
-	{ AS(pread_args), (sy_call_t *)pread },		/* 173 = pread */
-	{ AS(pwrite_args), (sy_call_t *)pwrite },	/* 174 = pwrite */
+	{ SYF_MPSAFE | AS(pread_args), (sy_call_t *)pread },	/* 173 = pread */
+	{ SYF_MPSAFE | AS(pwrite_args), (sy_call_t *)pwrite },	/* 174 = pwrite */
 	{ 0, (sy_call_t *)nosys },			/* 175 = nosys */
 	{ AS(ntp_adjtime_args), (sy_call_t *)ntp_adjtime },	/* 176 = ntp_adjtime */
 	{ 0, (sy_call_t *)nosys },			/* 177 = sfork */
@@ -323,8 +323,8 @@ struct sysent sysent[] = {
 	{ 0, (sy_call_t *)nosys },			/* 286 = nosys */
 	{ 0, (sy_call_t *)nosys },			/* 287 = nosys */
 	{ 0, (sy_call_t *)nosys },			/* 288 = nosys */
-	{ AS(preadv_args), (sy_call_t *)preadv },	/* 289 = preadv */
-	{ AS(pwritev_args), (sy_call_t *)pwritev },	/* 290 = pwritev */
+	{ SYF_MPSAFE | AS(preadv_args), (sy_call_t *)preadv },	/* 289 = preadv */
+	{ SYF_MPSAFE | AS(pwritev_args), (sy_call_t *)pwritev },	/* 290 = pwritev */
 	{ 0, (sy_call_t *)nosys },			/* 291 = nosys */
 	{ 0, (sy_call_t *)nosys },			/* 292 = nosys */
 	{ 0, (sy_call_t *)nosys },			/* 293 = nosys */
@@ -508,7 +508,7 @@ struct sysent sysent[] = {
 	{ AS(jail_attach_args), (sy_call_t *)jail_attach },	/* 471 = jail_attach */
 	{ AS(sys_set_tls_area_args), (sy_call_t *)sys_set_tls_area },	/* 472 = sys_set_tls_area */
 	{ AS(sys_get_tls_area_args), (sy_call_t *)sys_get_tls_area },	/* 473 = sys_get_tls_area */
-	{ AS(closefrom_args), (sy_call_t *)closefrom },	/* 474 = closefrom */
+	{ SYF_MPSAFE | AS(closefrom_args), (sy_call_t *)closefrom },	/* 474 = closefrom */
 	{ AS(stat_args), (sy_call_t *)stat },		/* 475 = stat */
 	{ AS(fstat_args), (sy_call_t *)fstat },		/* 476 = fstat */
 	{ AS(lstat_args), (sy_call_t *)lstat },		/* 477 = lstat */
diff --git a/sys/kern/kern_subr.c b/sys/kern/kern_subr.c
index e537cbe715..f1401a4d6c 100644
--- a/sys/kern/kern_subr.c
+++ b/sys/kern/kern_subr.c
@@ -37,7 +37,7 @@
  *
  *	@(#)kern_subr.c	8.3 (Berkeley) 1/21/94
  * $FreeBSD: src/sys/kern/kern_subr.c,v 1.31.2.2 2002/04/21 08:09:37 bde Exp $
- * $DragonFly: src/sys/kern/kern_subr.c,v 1.22 2006/04/26 17:42:53 dillon Exp $
+ * $DragonFly: src/sys/kern/kern_subr.c,v 1.23 2006/05/27 20:17:16 dillon Exp $
  */
 
 #include "opt_ddb.h"
@@ -322,6 +322,8 @@ phashinit(elements, type, nentries)
  * Copyin an iovec.  If the iovec array fits, use the preallocated small
  * iovec structure.  If it is too big, dynamically allocate an iovec array
  * of sufficient size.
+ *
+ * MPSAFE
  */
 int
 iovec_copyin(struct iovec *uiov, struct iovec **kiov, struct iovec *siov,
diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index 94203b0e25..6b2163376d 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -37,7 +37,7 @@
  *
  *	@(#)sys_generic.c	8.5 (Berkeley) 1/21/94
  * $FreeBSD: src/sys/kern/sys_generic.c,v 1.55.2.10 2001/03/17 10:39:32 peter Exp $
- * $DragonFly: src/sys/kern/sys_generic.c,v 1.30 2006/05/19 07:33:45 dillon Exp $
+ * $DragonFly: src/sys/kern/sys_generic.c,v 1.31 2006/05/27 20:17:16 dillon Exp $
  */
 
 #include "opt_ktrace.h"
@@ -85,6 +85,8 @@ static int	dofilewrite(int, struct file *, struct uio *, int, int *);
 
 /*
  * Read system call.
+ *
+ * MPSAFE
  */
 int
 read(struct read_args *uap)
@@ -113,6 +115,8 @@ read(struct read_args *uap)
 
 /*
  * Positioned (Pread) read system call
+ *
+ * MPSAFE
  */
 int
 pread(struct pread_args *uap)
@@ -141,6 +145,8 @@ pread(struct pread_args *uap)
 
 /*
  * Scatter read system call.
+ *
+ * MPSAFE
  */
 int
 readv(struct readv_args *uap)
@@ -170,6 +176,8 @@ readv(struct readv_args *uap)
 
 /*
  * Scatter positioned read system call.
+ *
+ * MPSAFE
  */
 int
 preadv(struct preadv_args *uap)
@@ -196,6 +204,9 @@ preadv(struct preadv_args *uap)
 	return(error);
 }
 
+/*
+ * MPSAFE
+ */
 int
 kern_preadv(int fd, struct uio *auio, int flags, int *res)
 {
@@ -223,6 +234,8 @@ kern_preadv(int fd, struct uio *auio, int flags, int *res)
 /*
  * Common code for readv and preadv that reads data in
  * from a file using the passed in uio, offset, and flags.
+ *
+ * MPALMOSTSAFE - ktrace needs help
  */
 static int
 dofileread(int fd, struct file *fp, struct uio *auio, int flags, int *res)
@@ -260,7 +273,9 @@ dofileread(int fd, struct file *fp, struct uio *auio, int flags, int *res)
 		if (error == 0) {
 			ktruio.uio_iov = ktriov;
 			ktruio.uio_resid = len - auio->uio_resid;
+			get_mplock();
 			ktrgenio(p, fd, UIO_READ, &ktruio, error);
+			rel_mplock();
 		}
 		FREE(ktriov, M_TEMP);
 	}
@@ -273,6 +288,8 @@ dofileread(int fd, struct file *fp, struct uio *auio, int flags, int *res)
 
 /*
  * Write system call
+ *
+ * MPSAFE
  */
 int
 write(struct write_args *uap)
@@ -302,6 +319,8 @@ write(struct write_args *uap)
 
 /*
  * Pwrite system call
+ *
+ * MPSAFE
  */
 int
 pwrite(struct pwrite_args *uap)
@@ -329,6 +348,9 @@ pwrite(struct pwrite_args *uap)
 	return(error);
 }
 
+/*
+ * MPSAFE
+ */
 int
 writev(struct writev_args *uap)
 {
@@ -357,6 +379,8 @@ writev(struct writev_args *uap)
 
 /*
  * Gather positioned write system call
+ *
+ * MPSAFE
  */
 int
 pwritev(struct pwritev_args *uap)
@@ -383,6 +407,9 @@ pwritev(struct pwritev_args *uap)
 	return(error);
 }
 
+/*
+ * MPSAFE
+ */
 int
 kern_pwritev(int fd, struct uio *auio, int flags, int *res)
 {
@@ -409,6 +436,8 @@ kern_pwritev(int fd, struct uio *auio, int flags, int *res)
 /*
  * Common code for writev and pwritev that writes data to
  * a file using the passed in uio, offset, and flags.
+ *
+ * MPALMOSTSAFE - ktrace needs help
  */
 static int
 dofilewrite(int fd, struct file *fp, struct uio *auio, int flags, int *res)
@@ -443,15 +472,20 @@ dofilewrite(int fd, struct file *fp, struct uio *auio, int flags, int *res)
 		    error == EINTR || error == EWOULDBLOCK))
 			error = 0;
 		/* Socket layer is responsible for issuing SIGPIPE. */
-		if (error == EPIPE)
+		if (error == EPIPE) {
+			get_mplock();
 			psignal(p, SIGPIPE);
+			rel_mplock();
+		}
 	}
 #ifdef KTRACE
 	if (ktriov != NULL) {
 		if (error == 0) {
 			ktruio.uio_iov = ktriov;
 			ktruio.uio_resid = len - auio->uio_resid;
+			get_mplock();
 			ktrgenio(p, fd, UIO_WRITE, &ktruio, error);
+			rel_mplock();
 		}
 		FREE(ktriov, M_TEMP);
 	}
diff --git a/sys/kern/syscalls.c b/sys/kern/syscalls.c
index 68c575b586..7b88400ef4 100644
--- a/sys/kern/syscalls.c
+++ b/sys/kern/syscalls.c
@@ -2,7 +2,7 @@
  * System call names.
  *
  * DO NOT EDIT-- this file is automatically generated.
- * $DragonFly: src/sys/kern/syscalls.c,v 1.35 2006/05/24 12:42:01 corecode Exp $
+ * $DragonFly: src/sys/kern/syscalls.c,v 1.36 2006/05/27 20:17:16 dillon Exp $
  * created from DragonFly: src/sys/kern/syscalls.master,v 1.35 2006/05/24 12:40:19 corecode Exp 
  */
 
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index e2bc03e902..0756267215 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -1,4 +1,4 @@
- $DragonFly: src/sys/kern/syscalls.master,v 1.35 2006/05/24 12:40:19 corecode Exp $
+ $DragonFly: src/sys/kern/syscalls.master,v 1.36 2006/05/27 20:17:16 dillon Exp $
 
 ; @(#)syscalls.master	8.2 (Berkeley) 1/13/94
 ; $FreeBSD: src/sys/kern/syscalls.master,v 1.72.2.10 2002/07/12 08:22:46 alfred Exp $
@@ -48,13 +48,13 @@
 0	STD	NOHIDE	{ int nosys(void); } syscall nosys_args int
 1	STD	NOHIDE	{ void sys_exit(int rval); } exit sys_exit_args void
 2	STD	POSIX	{ int fork(void); }
-3	STD	POSIX	{ ssize_t read(int fd, void *buf, size_t nbyte); }
-4	STD	POSIX	{ ssize_t write(int fd, const void *buf, size_t nbyte); }
+3	MPSAFE	STD	POSIX	{ ssize_t read(int fd, void *buf, size_t nbyte); }
+4	MPSAFE	STD	POSIX	{ ssize_t write(int fd, const void *buf, size_t nbyte); }
 5	STD	POSIX	{ int open(char *path, int flags, int mode); }
 ; XXX should be		{ int open(const char *path, int flags, ...); }
 ; but we're not ready for `const' or varargs.
 ; XXX man page says `mode_t mode'.
-6	STD	POSIX	{ int close(int fd); }
+6	MPSAFE	STD	POSIX	{ int close(int fd); }
 7	STD	BSD	{ int wait4(int pid, int *status, int options, \
 			    struct rusage *rusage); } wait4 wait_args int
 8	COMPAT	BSD	{ int creat(char *path, int mode); }
@@ -95,7 +95,7 @@
 38	COMPAT	POSIX	{ int stat(char *path, struct ostat *ub); }
 39	STD	POSIX	{ pid_t getppid(void); }
 40	COMPAT	POSIX	{ int lstat(char *path, struct ostat *ub); }
-41	STD	POSIX	{ int dup(u_int fd); }
+41	MPSAFE	STD	POSIX	{ int dup(u_int fd); }
 42	STD	POSIX	{ int pipe(void); }
 43	STD	POSIX	{ gid_t getegid(void); }
 44	STD	BSD	{ int profil(caddr_t samples, size_t size, \
@@ -156,9 +156,9 @@
 88	COMPAT	BSD	{ int sethostname(char *hostname, u_int len); } \
 			    sethostname sethostname_args int
 89	MPSAFE	STD	BSD	{ int getdtablesize(void); }
-90	STD	POSIX	{ int dup2(u_int from, u_int to); }
+90	MPSAFE	STD	POSIX	{ int dup2(u_int from, u_int to); }
 91	UNIMPL	BSD	getdopt
-92	STD	POSIX	{ int fcntl(int fd, int cmd, long arg); }
+92	MPSAFE	STD	POSIX	{ int fcntl(int fd, int cmd, long arg); }
 ; XXX should be		{ int fcntl(int fd, int cmd, ...); }
 ; but we're not ready for varargs.
 ; XXX man page says `int arg' too.
@@ -198,8 +198,8 @@
 118	STD	BSD	{ int getsockopt(int s, int level, int name, \
 			    caddr_t val, int *avalsize); }
 119	UNIMPL	NOHIDE	resuba (BSD/OS 2.x)
-120	STD	BSD	{ int readv(int fd, struct iovec *iovp, u_int iovcnt); }
-121	STD	BSD	{ int writev(int fd, struct iovec *iovp, \
+120	MPSAFE	STD	BSD	{ int readv(int fd, struct iovec *iovp, u_int iovcnt); }
+121	MPSAFE	STD	BSD	{ int writev(int fd, struct iovec *iovp, \
 			    u_int iovcnt); }
 122	STD	BSD	{ int settimeofday(struct timeval *tv, \
 			    struct timezone *tzp); }
@@ -274,9 +274,9 @@
 171	STD	BSD	{ int shmsys(int which, int a2, int a3, int a4); }
 ; XXX should be		{ int shmsys(int which, ...); }
 172	UNIMPL	NOHIDE	nosys
-173	STD	POSIX	{ ssize_t pread(int fd, void *buf, size_t nbyte, \
+173	MPSAFE	STD	POSIX	{ ssize_t pread(int fd, void *buf, size_t nbyte, \
 			    int pad, off_t offset); }
-174	STD	POSIX	{ ssize_t pwrite(int fd, const void *buf, \
+174	MPSAFE	STD	POSIX	{ ssize_t pwrite(int fd, const void *buf, \
 			    size_t nbyte, int pad, off_t offset); }
 175	UNIMPL	NOHIDE	nosys
 176	STD	BSD	{ int ntp_adjtime(struct timex *tp); }
@@ -429,8 +429,8 @@
 287	UNIMPL	NOHIDE	nosys
 288	UNIMPL	NOHIDE	nosys
 ; 289 and 290 from NetBSD (OpenBSD: 267 and 268)
-289	STD	BSD	{ ssize_t preadv(int fd, struct iovec *iovp, u_int iovcnt, off_t offset); }
-290	STD	BSD	{ ssize_t pwritev(int fd, struct iovec *iovp, u_int iovcnt, off_t offset); }
+289	MPSAFE	STD	BSD	{ ssize_t preadv(int fd, struct iovec *iovp, u_int iovcnt, off_t offset); }
+290	MPSAFE	STD	BSD	{ ssize_t pwritev(int fd, struct iovec *iovp, u_int iovcnt, off_t offset); }
 291	UNIMPL	NOHIDE	nosys
 292	UNIMPL	NOHIDE	nosys
 293	UNIMPL	NOHIDE	nosys
@@ -644,7 +644,7 @@
 471	STD	BSD	{ int jail_attach(int jid); }
 472	STD	BSD	{ int sys_set_tls_area(int which, struct tls_info *info, size_t infosize); }
 473	STD	BSD	{ int sys_get_tls_area(int which, struct tls_info *info, size_t infosize); }
-474	STD	BSD	{ int closefrom(int fd); }
+474	MPSAFE	STD	BSD	{ int closefrom(int fd); }
 475	STD	POSIX	{ int stat(const char *path, struct stat *ub); }
 476	STD	POSIX	{ int fstat(int fd, struct stat *sb); }
 477	STD	POSIX	{ int lstat(const char *path, struct stat *ub); }
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index efe6633b43..99d31c2239 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -12,7 +12,7 @@
  *		John S. Dyson.
  *
  * $FreeBSD: src/sys/kern/vfs_bio.c,v 1.242.2.20 2003/05/28 18:38:10 alc Exp $
- * $DragonFly: src/sys/kern/vfs_bio.c,v 1.76 2006/05/25 19:31:13 dillon Exp $
+ * $DragonFly: src/sys/kern/vfs_bio.c,v 1.77 2006/05/27 20:17:16 dillon Exp $
  */
 
 /*
@@ -56,6 +56,7 @@
 
 #include <sys/buf2.h>
 #include <sys/thread2.h>
+#include <sys/spinlock2.h>
 #include <vm/vm_page2.h>
 
 #include "opt_ddb.h"
@@ -94,8 +95,6 @@ static void vfs_setdirty(struct buf *bp);
 static void vfs_vmio_release(struct buf *bp);
 static int flushbufqueues(void);
 
-static int bd_request;
-
 static void buf_daemon (void);
 /*
  * bogus page -- for I/O to/from partially complete buffers
@@ -110,13 +109,16 @@ int runningbufspace;
 static int bufspace, maxbufspace,
 	bufmallocspace, maxbufmallocspace, lobufspace, hibufspace;
 static int bufreusecnt, bufdefragcnt, buffreekvacnt;
-static int needsbuffer;
 static int lorunningspace, hirunningspace, runningbufreq;
 static int numdirtybuffers, lodirtybuffers, hidirtybuffers;
 static int numfreebuffers, lofreebuffers, hifreebuffers;
 static int getnewbufcalls;
 static int getnewbufrestarts;
 
+static int needsbuffer;		/* locked by needsbuffer_spin */
+static int bd_request;		/* locked by needsbuffer_spin */
+static struct spinlock needsbuffer_spin;
+
 /*
  * Sysctls for operational control of the buffer cache.
  */
@@ -187,7 +189,9 @@ numdirtywakeup(int level)
 {
 	if (numdirtybuffers <= level) {
 		if (needsbuffer & VFS_BIO_NEED_DIRTYFLUSH) {
+			spin_lock_wr(&needsbuffer_spin);
 			needsbuffer &= ~VFS_BIO_NEED_DIRTYFLUSH;
+			spin_unlock_wr(&needsbuffer_spin);
 			wakeup(&needsbuffer);
 		}
 	}
@@ -211,7 +215,9 @@ bufspacewakeup(void)
 	 * process will be able to now.
 	 */
 	if (needsbuffer & VFS_BIO_NEED_BUFSPACE) {
+		spin_lock_wr(&needsbuffer_spin);
 		needsbuffer &= ~VFS_BIO_NEED_BUFSPACE;
+		spin_unlock_wr(&needsbuffer_spin);
 		wakeup(&needsbuffer);
 	}
 }
@@ -249,9 +255,11 @@ bufcountwakeup(void)
 {
 	++numfreebuffers;
 	if (needsbuffer) {
+		spin_lock_wr(&needsbuffer_spin);
 		needsbuffer &= ~VFS_BIO_NEED_ANY;
 		if (numfreebuffers >= hifreebuffers)
 			needsbuffer &= ~VFS_BIO_NEED_FREE;
+		spin_unlock_wr(&needsbuffer_spin);
 		wakeup(&needsbuffer);
 	}
 }
@@ -319,7 +327,9 @@ void
 bd_wakeup(int dirtybuflevel)
 {
 	if (bd_request == 0 && numdirtybuffers >= dirtybuflevel) {
+		spin_lock_wr(&needsbuffer_spin);
 		bd_request = 1;
+		spin_unlock_wr(&needsbuffer_spin);
 		wakeup(&bd_request);
 	}
 }
@@ -350,6 +360,8 @@ bufinit(void)
 	vm_offset_t bogus_offset;
 	int i;
 
+	spin_init(&needsbuffer_spin);
+
 	/* next, make a null set of free lists */
 	for (i = 0; i < BUFFER_QUEUES; i++)
 		TAILQ_INIT(&bufqueues[i]);
@@ -918,13 +930,16 @@ void
 bwillwrite(void)
 {
 	if (numdirtybuffers >= hidirtybuffers) {
-		crit_enter();
 		while (numdirtybuffers >= hidirtybuffers) {
 			bd_wakeup(1);
-			needsbuffer |= VFS_BIO_NEED_DIRTYFLUSH;
-			tsleep(&needsbuffer, 0, "flswai", 0);
+			spin_lock_wr(&needsbuffer_spin);
+			if (numdirtybuffers >= hidirtybuffers) {
+				needsbuffer |= VFS_BIO_NEED_DIRTYFLUSH;
+				msleep(&needsbuffer, &needsbuffer_spin, 0,
+				       "flswai", 0);
+			}
+			spin_unlock_wr(&needsbuffer_spin);
 		}
-		crit_exit();
 	}
 }
 
@@ -1875,8 +1890,10 @@ buf_daemon()
 			 * request and sleep until we are needed again.
 			 * The sleep is just so the suspend code works.
 			 */
+			spin_lock_wr(&needsbuffer_spin);
 			bd_request = 0;
-			tsleep(&bd_request, 0, "psleep", hz);
+			msleep(&bd_request, &needsbuffer_spin, 0, "psleep", hz);
+			spin_unlock_wr(&needsbuffer_spin);
 		} else {
 			/*
 			 * We couldn't find any flushable dirty buffers but
diff --git a/sys/kern/vfs_lock.c b/sys/kern/vfs_lock.c
index 80ef065df8..8a5789fc56 100644
--- a/sys/kern/vfs_lock.c
+++ b/sys/kern/vfs_lock.c
@@ -31,7 +31,7 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $DragonFly: src/sys/kern/vfs_lock.c,v 1.18 2006/05/24 03:23:31 dillon Exp $
+ * $DragonFly: src/sys/kern/vfs_lock.c,v 1.19 2006/05/27 20:17:16 dillon Exp $
  */
 
 /*
diff --git a/sys/sys/syscall-args b/sys/sys/syscall-args
index 4d9c3cb904..44c0bd9bb0 100644
--- a/sys/sys/syscall-args
+++ b/sys/sys/syscall-args
@@ -1,8 +1,8 @@
 # System call argument table.
 # DO NOT EDIT-- this file is automatically generated.
-# $DragonFly: src/sys/sys/Attic/syscall-args,v 1.20 2006/04/26 17:17:57 dillon Exp $
+# $DragonFly: src/sys/sys/Attic/syscall-args,v 1.21 2006/05/27 20:17:17 dillon Exp $
 
-# Created from DragonFly: src/sys/kern/syscalls.master,v 1.31 2006/03/24 06:45:04 dillon Exp 
+# Created from DragonFly: src/sys/kern/syscalls.master,v 1.35 2006/05/24 12:40:19 corecode Exp 
 
 int	syscall	nosys	nosys_args
 void	exit	sys_exit	sys_exit_args	int	rval
diff --git a/sys/sys/syscall-hide.h b/sys/sys/syscall-hide.h
index 2021caf7dd..e2eb35d7ec 100644
--- a/sys/sys/syscall-hide.h
+++ b/sys/sys/syscall-hide.h
@@ -2,8 +2,8 @@
  * System call hiders.
  *
  * DO NOT EDIT-- this file is automatically generated.
- * $DragonFly: src/sys/sys/syscall-hide.h,v 1.36 2006/04/26 17:17:57 dillon Exp $
- * created from DragonFly: src/sys/kern/syscalls.master,v 1.31 2006/03/24 06:45:04 dillon Exp 
+ * $DragonFly: src/sys/sys/syscall-hide.h,v 1.37 2006/05/27 20:17:17 dillon Exp $
+ * created from DragonFly: src/sys/kern/syscalls.master,v 1.35 2006/05/24 12:40:19 corecode Exp 
  */
 
 #ifdef COMPAT_43
diff --git a/sys/sys/syscall.h b/sys/sys/syscall.h
index 78af2dacbb..e7260c1af8 100644
--- a/sys/sys/syscall.h
+++ b/sys/sys/syscall.h
@@ -2,8 +2,8 @@
  * System call numbers.
  *
  * DO NOT EDIT-- this file is automatically generated.
- * $DragonFly: src/sys/sys/syscall.h,v 1.36 2006/04/26 17:17:57 dillon Exp $
- * created from DragonFly: src/sys/kern/syscalls.master,v 1.31 2006/03/24 06:45:04 dillon Exp 
+ * $DragonFly: src/sys/sys/syscall.h,v 1.37 2006/05/27 20:17:17 dillon Exp $
+ * created from DragonFly: src/sys/kern/syscalls.master,v 1.35 2006/05/24 12:40:19 corecode Exp 
  */
 
 #define	SYS_syscall	0
diff --git a/sys/sys/syscall.mk b/sys/sys/syscall.mk
index 4b3b17bbd4..16aefbae72 100644
--- a/sys/sys/syscall.mk
+++ b/sys/sys/syscall.mk
@@ -1,7 +1,7 @@
 # DragonFly system call names.
 # DO NOT EDIT-- this file is automatically generated.
-# $DragonFly: src/sys/sys/syscall.mk,v 1.36 2006/04/26 17:17:57 dillon Exp $
-# created from DragonFly: src/sys/kern/syscalls.master,v 1.31 2006/03/24 06:45:04 dillon Exp 
+# $DragonFly: src/sys/sys/syscall.mk,v 1.37 2006/05/27 20:17:17 dillon Exp $
+# created from DragonFly: src/sys/kern/syscalls.master,v 1.35 2006/05/24 12:40:19 corecode Exp 
 MIASM =  \
 	syscall.o \
 	exit.o \
diff --git a/sys/sys/sysproto.h b/sys/sys/sysproto.h
index b37232431b..884c876756 100644
--- a/sys/sys/sysproto.h
+++ b/sys/sys/sysproto.h
@@ -2,8 +2,8 @@
  * System call prototypes.
  *
  * DO NOT EDIT-- this file is automatically generated.
- * $DragonFly: src/sys/sys/sysproto.h,v 1.36 2006/04/26 17:17:57 dillon Exp $
- * created from DragonFly: src/sys/kern/syscalls.master,v 1.31 2006/03/24 06:45:04 dillon Exp 
+ * $DragonFly: src/sys/sys/sysproto.h,v 1.37 2006/05/27 20:17:17 dillon Exp $
+ * created from DragonFly: src/sys/kern/syscalls.master,v 1.35 2006/05/24 12:40:19 corecode Exp 
  */
 
 #ifndef _SYS_SYSPROTO_H_
diff --git a/sys/sys/sysunion.h b/sys/sys/sysunion.h
index 079ec5f176..df88c20e9f 100644
--- a/sys/sys/sysunion.h
+++ b/sys/sys/sysunion.h
@@ -2,8 +2,8 @@
  * Union of syscall args for messaging.
  *
  * DO NOT EDIT-- this file is automatically generated.
- * $DragonFly: src/sys/sys/sysunion.h,v 1.33 2006/04/26 17:17:57 dillon Exp $
- * created from DragonFly: src/sys/kern/syscalls.master,v 1.31 2006/03/24 06:45:04 dillon Exp 
+ * $DragonFly: src/sys/sys/sysunion.h,v 1.34 2006/05/27 20:17:17 dillon Exp $
+ * created from DragonFly: src/sys/kern/syscalls.master,v 1.35 2006/05/24 12:40:19 corecode Exp 
  */
 
 union sysunion {
diff --git a/sys/sys/uio.h b/sys/sys/uio.h
index 5304d86958..e325bebd43 100644
--- a/sys/sys/uio.h
+++ b/sys/sys/uio.h
@@ -32,7 +32,7 @@
  *
  *	@(#)uio.h	8.5 (Berkeley) 2/22/94
  * $FreeBSD: src/sys/sys/uio.h,v 1.11.2.1 2001/09/28 16:58:35 dillon Exp $
- * $DragonFly: src/sys/sys/uio.h,v 1.13 2006/05/21 03:43:47 dillon Exp $
+ * $DragonFly: src/sys/sys/uio.h,v 1.14 2006/05/27 20:17:17 dillon Exp $
  */
 
 #ifndef _SYS_UIO_H_
@@ -105,6 +105,9 @@ int	uioread (int, struct uio *, struct vm_object *, int *);
 int	iovec_copyin(struct iovec *, struct iovec **, struct iovec *,
 			    size_t, int *);
 
+/*
+ * MPSAFE
+ */
 static __inline void
 iovec_free(struct iovec **kiov, struct iovec *siov)
 {
-- 
2.41.0