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Code Issues Releases Activity

Don't acquire Giant unconditionally.

Browse Source 
Reviewed by:	rwatson
This commit is contained in:
Wojciech A. Koszek 2007-05-06 12:00:38 +00:00
parent 0738dfc386
commit 9e2894466a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=169307
1 changed files with 20 additions and 14 deletions
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34
sys/kern/uipc_usrreq.c
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@ -375,7 +375,7 @@ uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct sockaddr_un *soun = (struct sockaddr_un *)nam;
struct vattr vattr;
int error, namelen;
int error, namelen, vfslocked;
struct nameidata nd;
struct unpcb *unp;
struct vnode *vp;
@ -414,16 +414,16 @@ uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
buf = malloc(namelen + 1, M_TEMP, M_WAITOK);
strlcpy(buf, soun->sun_path, namelen + 1);
mtx_lock(&Giant);
restart:
mtx_assert(&Giant, MA_OWNED);
NDINIT(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME, UIO_SYSSPACE,
buf, td);
vfslocked = 0;
NDINIT(&nd, CREATE, MPSAFE | NOFOLLOW | LOCKPARENT | SAVENAME,
UIO_SYSSPACE, buf, td);
/* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
error = namei(&nd);
if (error)
goto error;
vp = nd.ni_vp;
vfslocked = NDHASGIANT(&nd);
if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {
NDFREE(&nd, NDF_ONLY_PNBUF);
if (nd.ni_dvp == vp)
@ -438,6 +438,7 @@ uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH);
if (error)
goto error;
VFS_UNLOCK_GIANT(vfslocked);
goto restart;
}
VATTR_NULL(&vattr);
@ -471,15 +472,15 @@ uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
UNP_GLOBAL_WUNLOCK();
VOP_UNLOCK(vp, 0, td);
vn_finished_write(mp);
mtx_unlock(&Giant);
VFS_UNLOCK_GIANT(vfslocked);
free(buf, M_TEMP);
return (0);
error:
VFS_UNLOCK_GIANT(vfslocked);
UNP_PCB_LOCK(unp);
unp->unp_flags &= ~UNP_BINDING;
UNP_PCB_UNLOCK(unp);
mtx_unlock(&Giant);
free(buf, M_TEMP);
return (error);
}
@ -1121,7 +1122,7 @@ unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
struct vnode *vp;
struct socket *so2, *so3;
struct unpcb *unp, *unp2, *unp3;
int error, len;
int error, len, vfslocked;
struct nameidata nd;
char buf[SOCK_MAXADDRLEN];
struct sockaddr *sa;
@ -1146,14 +1147,15 @@ unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
UNP_PCB_UNLOCK(unp);
sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
mtx_lock(&Giant);
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, td);
NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf,
td);
error = namei(&nd);
if (error)
vp = NULL;
else
vp = nd.ni_vp;
ASSERT_VOP_LOCKED(vp, "unp_connect");
vfslocked = NDHASGIANT(&nd);
NDFREE(&nd, NDF_ONLY_PNBUF);
if (error)
goto bad;
@ -1170,7 +1172,7 @@ unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td);
if (error)
goto bad;
mtx_unlock(&Giant);
VFS_UNLOCK_GIANT(vfslocked);
unp = sotounpcb(so);
KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
@ -1259,12 +1261,16 @@ unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
UNP_PCB_UNLOCK(unp);
bad2:
UNP_GLOBAL_WUNLOCK();
mtx_lock(&Giant);
if (vfslocked)
/*
* Giant has been previously acquired. This means filesystem
* isn't MPSAFE. Do it once again.
*/
mtx_lock(&Giant);
bad:
mtx_assert(&Giant, MA_OWNED);
if (vp != NULL)
vput(vp);
mtx_unlock(&Giant);
VFS_UNLOCK_GIANT(vfslocked);
free(sa, M_SONAME);
UNP_GLOBAL_WLOCK();
UNP_PCB_LOCK(unp);