tmpfs kqueue

[Ted Unangst]

As noticed by aja, kqueue doesn't work on tmpfs.

Copy more better bits from ufs instead of using generic bits.

Index: tmpfs_vnops.c
===================================================================
RCS file: /cvs/src/sys/tmpfs/tmpfs_vnops.c,v
retrieving revision 1.12
diff -u -p -r1.12 tmpfs_vnops.c
--- tmpfs_vnops.c       7 Jan 2014 04:44:56 -0000       1.12
+++ tmpfs_vnops.c       21 Jan 2014 20:34:26 -0000
@@ -53,6 +53,7 @@ __KERNEL_RCSID(0, "$NetBSD: tmpfs_vnops.
 #include <sys/vnode.h>
 #include <sys/lockf.h>
 #include <sys/poll.h>
+#include <sys/file.h>
 
 #include <uvm/uvm.h>
 
@@ -60,6 +61,8 @@ __KERNEL_RCSID(0, "$NetBSD: tmpfs_vnops.
 #include <tmpfs/tmpfs_vnops.h>
 #include <tmpfs/tmpfs.h>
 
+int tmpfs_kqfilter(void *v);
+
 /*
  * vnode operations vector used for files stored in a tmpfs file system.
  */
@@ -76,7 +79,7 @@ struct vops tmpfs_vops = {
        .vop_write      = tmpfs_write,
        .vop_ioctl      = tmpfs_ioctl,
        .vop_poll       = tmpfs_poll,
-       .vop_kqfilter   = vop_generic_kqfilter,
+       .vop_kqfilter   = tmpfs_kqfilter,
        .vop_revoke     = vop_generic_revoke,
        .vop_fsync      = tmpfs_fsync,
        .vop_remove     = tmpfs_remove,
@@ -2567,4 +2570,104 @@ tmpfs_rename_abort(void *v)
        VOP_ABORTOP(fdvp, fcnp);
        vrele(fdvp);
        vrele(fvp);
+}
+
+void filt_tmpfsdetach(struct knote *kn);
+int filt_tmpfsread(struct knote *kn, long hint);
+int filt_tmpfswrite(struct knote *kn, long hint);
+int filt_tmpfsvnode(struct knote *kn, long hint);
+
+struct filterops tmpfsread_filtops = 
+       { 1, NULL, filt_tmpfsdetach, filt_tmpfsread };
+struct filterops tmpfswrite_filtops = 
+       { 1, NULL, filt_tmpfsdetach, filt_tmpfswrite };
+struct filterops tmpfsvnode_filtops = 
+       { 1, NULL, filt_tmpfsdetach, filt_tmpfsvnode };
+
+int
+tmpfs_kqfilter(void *v)
+{
+       struct vop_kqfilter_args *ap = v;
+       struct vnode *vp = ap->a_vp;
+       struct knote *kn = ap->a_kn;
+
+       switch (kn->kn_filter) {
+       case EVFILT_READ:
+               kn->kn_fop = &tmpfsread_filtops;
+               break;
+       case EVFILT_WRITE:
+               kn->kn_fop = &tmpfswrite_filtops;
+               break;
+       case EVFILT_VNODE:
+               kn->kn_fop = &tmpfsvnode_filtops;
+               break;
+       default:
+               return (EINVAL);
+       }
+
+       kn->kn_hook = (caddr_t)vp;
+
+       SLIST_INSERT_HEAD(&vp->v_selectinfo.si_note, kn, kn_selnext);
+
+       return (0);
+}
+
+void
+filt_tmpfsdetach(struct knote *kn)
+{
+       struct vnode *vp = (struct vnode *)kn->kn_hook;
+
+       SLIST_REMOVE(&vp->v_selectinfo.si_note, kn, knote, kn_selnext);
+}
+
+int
+filt_tmpfsread(struct knote *kn, long hint)
+{
+       struct vnode *vp = (struct vnode *)kn->kn_hook;
+       tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp);
+
+       /*
+        * filesystem is gone, so set the EOF flag and schedule 
+        * the knote for deletion.
+        */
+       if (hint == NOTE_REVOKE) {
+               kn->kn_flags |= (EV_EOF | EV_ONESHOT);
+               return (1);
+       }
+
+        kn->kn_data = node->tn_size - kn->kn_fp->f_offset;
+       if (kn->kn_data == 0 && kn->kn_sfflags & NOTE_EOF) {
+               kn->kn_fflags |= NOTE_EOF;
+               return (1);
+       }
+
+        return (kn->kn_data != 0);
+}
+
+int
+filt_tmpfswrite(struct knote *kn, long hint)
+{
+       /*
+        * filesystem is gone, so set the EOF flag and schedule 
+        * the knote for deletion.
+        */
+       if (hint == NOTE_REVOKE) {
+               kn->kn_flags |= (EV_EOF | EV_ONESHOT);
+               return (1);
+       }
+
+        kn->kn_data = 0;
+        return (1);
+}
+
+int
+filt_tmpfsvnode(struct knote *kn, long hint)
+{
+       if (kn->kn_sfflags & hint)
+               kn->kn_fflags |= hint;
+       if (hint == NOTE_REVOKE) {
+               kn->kn_flags |= EV_EOF;
+               return (1);
+       }
+       return (kn->kn_fflags != 0);
 }