PERFORCE change 114126 for review

Christian S.J. Peron csjp at FreeBSD.org
Tue Feb 6 22:08:43 UTC 2007


http://perforce.freebsd.org/chv.cgi?CH=114126

Change 114126 by csjp at csjp_rnd01 on 2007/02/06 22:08:32

	Backup the previous timeout code, this was a mistake. Instead take
	the following approach:
	
	- Implement a new ioctl(2) command: BIOCROTZBUF to manually trigger
	  buffer rotations if the hold buffer is NULL and the store buffer
	  contains some packet data.  This ioctl works much like BIOCGETZNEXT 
	  only it doesn't may attention to the immediate flag.  If we are
	  unable to rotate the buffer, we return NULL back to userspace    
	  telling them to try again next wake up.

Affected files ...

.. //depot/projects/zcopybpf/src/sys/net/bpf.c#12 edit
.. //depot/projects/zcopybpf/src/sys/net/bpf.h#7 edit
.. //depot/projects/zcopybpf/src/sys/net/bpf_zerocopy.c#12 edit
.. //depot/projects/zcopybpf/src/sys/net/bpf_zerocopy.h#4 edit

Differences ...

==== //depot/projects/zcopybpf/src/sys/net/bpf.c#12 (text+ko) ====

@@ -310,14 +310,13 @@
 }
 
 static int
-bpf_ioctl_getznext(struct thread *td, struct bpf_d *d, struct bpf_zbuf *bz,
-    int timed_out)
+bpf_ioctl_getznext(struct thread *td, struct bpf_d *d, struct bpf_zbuf *bz)
 {
 
 	if (d->bd_bufmode != BPF_BUFMODE_ZBUF)
 		return (EOPNOTSUPP);
 #ifdef BPF_ZEROCOPY
-	return (bpf_zerocopy_ioctl_getznext(td, d, bz, timed_out));
+	return (bpf_zerocopy_ioctl_getznext(td, d, bz));
 #else
 	panic("bpf_ioctl_getznext");
 #endif
@@ -929,7 +928,7 @@
     struct thread *td)
 {
 	struct bpf_d *d = dev->si_drv1;
-	int timed_out, error = 0;
+	int error = 0;
 	
 	/* 
 	 * Refresh PID associated with this descriptor.
@@ -938,13 +937,6 @@
 	d->bd_pid = td->td_proc->p_pid;
 	if (d->bd_state == BPF_WAITING)
 		callout_stop(&d->bd_callout);
-	/*
-	 * Before we clobber the BPF state, check to see if this descriptor
-	 * was timed out.  If so, we capture that bit of information so we
-	 * can pass it to bpf_ioctl_getznext() so that it knows to rotate
-	 * the buffers.
-	 */
-	timed_out = (d->bd_state == BPF_TIMED_OUT) ? 1 : 0;
 	d->bd_state = BPF_IDLE;
 	BPFD_UNLOCK(d);
 
@@ -1287,11 +1279,14 @@
 		return (bpf_ioctl_getzmax(td, d, (u_int *)addr));
 
 	case BIOCGETZNEXT:
-		return (bpf_ioctl_getznext(td, d, (struct bpf_zbuf *)addr,
-		    timed_out));
+		return (bpf_ioctl_getznext(td, d, (struct bpf_zbuf *)addr));
 
 	case BIOCSETZBUF:
 		return (bpf_ioctl_setzbuf(td, d, (struct bpf_zbuf *)addr));
+
+	case BIOCROTZBUF:
+		return (bpf_zerocopy_ioctl_rotate(td, d, (struct bpf_zbuf *)
+		    addr));
 	}
 	return (error);
 }
@@ -1730,9 +1725,9 @@
 	}
 	else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT)
 		/*
-		 * Immediate mode is set, or the read timeout has
-		 * already expired during a select call.  A packet
-		 * arrived, so the reader should be woken up.
+		 * Immediate mode is set, or the read timeout has already
+		 * expired during a select call.  A packet arrived, so the
+		 * reader should be woken up.
 		 */
 		do_wakeup = 1;
 

==== //depot/projects/zcopybpf/src/sys/net/bpf.h#7 (text+ko) ====

@@ -153,7 +153,7 @@
 #define	BIOCGETZMAX	_IOR('B', 128, u_int)
 #define	BIOCGETZNEXT	_IOR('B', 129, struct bpf_zbuf)
 #define	BIOCSETZBUF	_IOW('B', 130, struct bpf_zbuf)
-
+#define	BIOCROTZBUF	_IOR('B', 131, struct bpf_zbuf)
 /*
  * Structure prepended to each packet.
  */
@@ -186,7 +186,10 @@
 	volatile u_int	bzh_kernel_gen;	/* Kernel generation number. */
 	volatile u_int	bzh_kernel_len;	/* Length of buffer. */
 	volatile u_int	bzh_user_gen;	/* User generation number. */
-	u_int	_bzh_pad[5];		/* Padding out to 32-byte boundary. */
+	void	*bzh_hbuf;
+	void	*bzh_fbuf;
+	void	*bzh_sbuf;
+	u_char	_bzh_pad[28];
 };
 
 /*

==== //depot/projects/zcopybpf/src/sys/net/bpf_zerocopy.c#12 (text+ko) ====

@@ -374,6 +374,9 @@
 	KASSERT(zb != NULL, ("bpf_zerocopy_bufheld: zb == NULL"));
 	zb->zb_header->bzh_kernel_len = d->bd_hlen;
 	zb->zb_header->bzh_kernel_gen++;
+	zb->zb_header->bzh_hbuf = d->bd_hbuf;
+	zb->zb_header->bzh_fbuf = d->bd_fbuf;
+	zb->zb_header->bzh_sbuf = d->bd_sbuf;
 }
 
 /*
@@ -548,7 +551,7 @@
  */
 int
 bpf_zerocopy_ioctl_getznext(struct thread *td, struct bpf_d *d,
-    struct bpf_zbuf *bz, int timed_out)
+    struct bpf_zbuf *bz)
 {
 	struct zbuf *zb;
 
@@ -564,9 +567,10 @@
 	 * held buffer.
 	 */
 	BPFD_LOCK(d);
-	if ((timed_out || d->bd_immediate) && d->bd_hbuf == NULL
-	    && d->bd_slen != 0)
+	if (d->bd_immediate && d->bd_hbuf == NULL
+	    && d->bd_slen != 0) {
 		ROTATE_BUFFERS(d);
+	}
 	bzero(bz, sizeof(*bz));
 	if (d->bd_hbuf != NULL) {
 		zb = (struct zbuf *)d->bd_hbuf;
@@ -577,6 +581,23 @@
 	return (0);
 }
 
+int
+bpf_zerocopy_ioctl_rotate(struct thread *td, struct bpf_d *d,
+    struct bpf_zbuf *bz)
+{
+	struct zbuf *bzh;
+
+	BPFD_LOCK(d);
+	bzero(bz, sizeof(*bz));
+	if (d->bd_hbuf == NULL && d->bd_slen != 0) {
+		ROTATE_BUFFERS(d);
+		bzh = (struct zbuf *)d->bd_hbuf;
+		bz->bz_bufa = (void *)bzh->zb_uaddr;
+		bz->bz_buflen = d->bd_hlen;
+	}
+	BPFD_UNLOCK(d);
+	return (0);
+}
 /*
  * Ioctl to configure zero-copy buffers -- may be done only once.
  */

==== //depot/projects/zcopybpf/src/sys/net/bpf_zerocopy.h#4 (text+ko) ====

@@ -50,10 +50,11 @@
 int	bpf_zerocopy_ioctl_getzmax(struct thread *td, struct bpf_d *d,
 	    u_int *i);
 int	bpf_zerocopy_ioctl_getznext(struct thread *td, struct bpf_d *d,
-	    struct bpf_zbuf *bz, int timed_out);
+	    struct bpf_zbuf *bz);
 int	bpf_zerocopy_ioctl_setzbuf(struct thread *td, struct bpf_d *d,
 	    struct bpf_zbuf *bz);
 int	bpf_zerocopy_uiomove(struct bpf_d *d, caddr_t buf, u_int len,
 	    struct uio *uio);
-
+int	bpf_zerocopy_ioctl_rotate(struct thread *td, struct bpf_d *d,
+	    struct bpf_zbuf *bz);
 #endif /* !_NET_BPF_ZEROCOPY_H_ */


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