This is what was "fdfix2.patch," a fix for fd sharing. It's pretty

far-reaching in fd-land, so you'll want to consult the code for
changes.  The biggest change is that now, you don't use
	fp->f_ops->fo_foo(fp, bar)
but instead
	fo_foo(fp, bar),
which increments and decrements the fp refcount upon entry and exit.
Two new calls, fhold() and fdrop(), are provided.  Each does what it
seems like it should, and if fdrop() brings the refcount to zero, the
fd is freed as well.

Thanks to peter ("to hell with it, it looks ok to me.") for his review.
Thanks to msmith for keeping me from putting locks everywhere :)

Reviewed by:	peter

1 files changed, 10 insertions, 11 deletions

diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index e187c21..1371f44 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -176,7 +176,7 @@ dofileread(p, fp, fd, buf, nbyte, offset, flags)
 		ktriov = aiov;
 #endif
 	cnt = nbyte;
-	if ((error = (*fp->f_ops->fo_read)(fp, &auio, fp->f_cred, flags)))
+	if ((error = fo_read(fp, &auio, fp->f_cred, flags, p)))
 		if (auio.uio_resid != cnt && (error == ERESTART ||
 		    error == EINTR || error == EWOULDBLOCK))
 			error = 0;
@@ -256,7 +256,7 @@ readv(p, uap)
 	}
 #endif
 	cnt = auio.uio_resid;
-	if ((error = (*fp->f_ops->fo_read)(fp, &auio, fp->f_cred, 0)))
+	if ((error = fo_read(fp, &auio, fp->f_cred, 0, p)))
 		if (auio.uio_resid != cnt && (error == ERESTART ||
 		    error == EINTR || error == EWOULDBLOCK))
 			error = 0;
@@ -360,7 +360,7 @@ dofilewrite(p, fp, fd, buf, nbyte, offset, flags)
 		ktriov = aiov;
 #endif
 	cnt = nbyte;
-	if ((error = (*fp->f_ops->fo_write)(fp, &auio, fp->f_cred, flags))) {
+	if ((error = fo_write(fp, &auio, fp->f_cred, flags, p))) {
 		if (auio.uio_resid != cnt && (error == ERESTART ||
 		    error == EINTR || error == EWOULDBLOCK))
 			error = 0;
@@ -444,7 +444,7 @@ writev(p, uap)
 	}
 #endif
 	cnt = auio.uio_resid;
-	if ((error = (*fp->f_ops->fo_write)(fp, &auio, fp->f_cred, 0))) {
+	if ((error = fo_write(fp, &auio, fp->f_cred, 0, p))) {
 		if (auio.uio_resid != cnt && (error == ERESTART ||
 		    error == EINTR || error == EWOULDBLOCK))
 			error = 0;
@@ -549,7 +549,7 @@ ioctl(p, uap)
 			fp->f_flag |= FNONBLOCK;
 		else
 			fp->f_flag &= ~FNONBLOCK;
-		error = (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
+		error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, p);
 		break;
 
 	case FIOASYNC:
@@ -557,11 +557,11 @@ ioctl(p, uap)
 			fp->f_flag |= FASYNC;
 		else
 			fp->f_flag &= ~FASYNC;
-		error = (*fp->f_ops->fo_ioctl)(fp, FIOASYNC, (caddr_t)&tmp, p);
+		error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, p);
 		break;
 
 	default:
-		error = (*fp->f_ops->fo_ioctl)(fp, com, data, p);
+		error = fo_ioctl(fp, com, data, p);
 		/*
 		 * Copy any data to user, size was
 		 * already set and checked above.
@@ -740,8 +740,7 @@ selscan(p, ibits, obits, nfd)
 				fp = fdp->fd_ofiles[fd];
 				if (fp == NULL)
 					return (EBADF);
-				if ((*fp->f_ops->fo_poll)(fp, flag[msk],
-				    fp->f_cred, p)) {
+				if (fo_poll(fp, flag[msk], fp->f_cred, p)) {
 					obits[msk][(fd)/NFDBITS] |=
 						(1 << ((fd) % NFDBITS));
 					n++;
@@ -868,8 +867,8 @@ pollscan(p, fds, nfd)
 				 * Note: backend also returns POLLHUP and
 				 * POLLERR if appropriate.
 				 */
-				fds->revents = (*fp->f_ops->fo_poll)(fp,
-				    fds->events, fp->f_cred, p);
+				fds->revents = fo_poll(fp, fds->events,
+				    fp->f_cred, p);
 				if (fds->revents != 0)
 					n++;
 			}