d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Clean up the fifo_open() implementation:

Browse Source 
Restructure the error handling portion of the resource allocation
        code to eliminate duplicated code.

        Test for the O_NONBLOCK && fi_readers == 0 case before incrementing
        fi_writers and modifying the the socket flag to avoid having to
        undo these operations in this error case.

        Restructure and simplify the code that handles blocking opens.

There should be no change to functionality.
This commit is contained in:
Don Lewis 2003-06-13 06:58:11 +00:00
parent 33a609ece0
commit b156281658
1 changed files with 30 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

75
sys/fs/fifofs/fifo_vnops.c
View File

@ -172,40 +172,33 @@ fifo_open(ap)
struct vnode *vp = ap->a_vp;
struct fifoinfo *fip;
struct thread *td = ap->a_td;
struct ucred *cred = ap->a_cred;
struct socket *rso, *wso;
int error;
if ((fip = vp->v_fifoinfo) == NULL) {
MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_VNODE, M_WAITOK);
vp->v_fifoinfo = fip;
error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0,
ap->a_td->td_ucred, ap->a_td);
if (error) {
free(fip, M_VNODE);
vp->v_fifoinfo = NULL;
return (error);
}
error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0, cred, td);
if (error)
goto fail1;
fip->fi_readsock = rso;
error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0,
ap->a_td->td_ucred, ap->a_td);
if (error) {
(void)soclose(rso);
free(fip, M_VNODE);
vp->v_fifoinfo = NULL;
return (error);
}
error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0, cred, td);
if (error)
goto fail2;
fip->fi_writesock = wso;
error = unp_connect2(wso, rso);
if (error) {
(void)soclose(wso);
fail2:
(void)soclose(rso);
fail1:
free(fip, M_VNODE);
vp->v_fifoinfo = NULL;
return (error);
}
fip->fi_readers = fip->fi_writers = 0;
wso->so_snd.sb_lowat = PIPE_BUF;
rso->so_state |= SS_CANTRCVMORE;
vp->v_fifoinfo = fip;
}
/*
@ -233,6 +226,10 @@ fifo_open(ap)
}
}
if (ap->a_mode & FWRITE) {
if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
VI_UNLOCK(vp);
return (ENXIO);
}
fip->fi_writers++;
if (fip->fi_writers == 1) {
fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
@ -244,8 +241,8 @@ fifo_open(ap)
}
}
}
if ((ap->a_mode & FREAD) && (ap->a_mode & O_NONBLOCK) == 0) {
if (fip->fi_writers == 0) {
if ((ap->a_mode & O_NONBLOCK) == 0) {
if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
VOP_UNLOCK(vp, 0, td);
error = msleep(&fip->fi_readers, VI_MTX(vp),
PCATCH | PSOCK, "fifoor", 0);
@ -263,36 +260,24 @@ fifo_open(ap)
* that we must wait for.
*/
}
}
if (ap->a_mode & FWRITE) {
if (ap->a_mode & O_NONBLOCK) {
if (fip->fi_readers == 0) {
VI_UNLOCK(vp);
if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) {
VOP_UNLOCK(vp, 0, td);
error = msleep(&fip->fi_writers, VI_MTX(vp),
PCATCH | PSOCK, "fifoow", 0);
vn_lock(vp,
LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK, td);
if (error) {
fip->fi_writers--;
if (fip->fi_writers == 0)
socantrcvmore(fip->fi_readsock);
return (ENXIO);
}
} else {
if (fip->fi_readers == 0) {
VOP_UNLOCK(vp, 0, td);
error = msleep(&fip->fi_writers, VI_MTX(vp),
PCATCH | PSOCK, "fifoow", 0);
vn_lock(vp,
LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK, td);
if (error) {
fip->fi_writers--;
if (fip->fi_writers == 0)
socantrcvmore(fip->fi_readsock);
return (error);
}
/*
* We must have got woken up because we had
* a reader. That (and not still having one)
* is the condition that we must wait for.
*/
return (0);
return (error);
}
/*
* We must have got woken up because we had
* a reader. That (and not still having one)
* is the condition that we must wait for.
*/
return (0);
}
}
VI_UNLOCK(vp);