Remove the sleep from the buffer allocation routine.

The buffer must be allocated (or even changed) before the interface is set
and thus, there is no need to verify if the buffer is in use.

MFC after:	2 weeks
Sponsored by:	Rubicon Communications (Netgate)

sys/net/bpf_buffer.c

@@ -79,8 +79,6 @@ __FBSDID("$FreeBSD$");
 #include <net/bpf_buffer.h>
 #include <net/bpfdesc.h>
 
-#define PRINET  26			/* interruptible */
-
 /*
  * Implement historical kernel memory buffering model for BPF: two malloc(9)
  * kernel buffers are hung off of the descriptor.  The size is fixed prior to
@@ -191,9 +189,6 @@ bpf_buffer_ioctl_sblen(struct bpf_d *d, u_int *i)
 		return (EINVAL);
 	}
 
-	while (d->bd_hbuf_in_use)
-		mtx_sleep(&d->bd_hbuf_in_use, &d->bd_lock,
-		    PRINET, "bd_hbuf", 0);
 	/* Free old buffers if set */
 	if (d->bd_fbuf != NULL)
 		free(d->bd_fbuf, M_BPF);