[src/trunk]: src/sys/fs/tmpfs Allocate direntp on the stack in tmpfs_dir_getd...

[pedro <pedro%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d09aefcfa659
branches:  trunk
changeset: 792577:d09aefcfa659
user:      pedro <pedro%NetBSD.org@localhost>
date:      Wed Jan 08 16:11:04 2014 +0000

description:
Allocate direntp on the stack in tmpfs_dir_getdents(), thus saving
calls to kmem_zalloc() and kmem_free(); OK rmind@. From OpenBSD.

diffstat:

 sys/fs/tmpfs/tmpfs_subr.c |  37 ++++++++++++++++++-------------------
 1 files changed, 18 insertions(+), 19 deletions(-)

diffs (96 lines):

diff -r db687344e602 -r d09aefcfa659 sys/fs/tmpfs/tmpfs_subr.c
--- a/sys/fs/tmpfs/tmpfs_subr.c Wed Jan 08 12:30:27 2014 +0000
+++ b/sys/fs/tmpfs/tmpfs_subr.c Wed Jan 08 16:11:04 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tmpfs_subr.c,v 1.93 2014/01/03 09:53:12 hannken Exp $  */
+/*     $NetBSD: tmpfs_subr.c,v 1.94 2014/01/08 16:11:04 pedro Exp $    */
 
 /*
  * Copyright (c) 2005-2013 The NetBSD Foundation, Inc.
@@ -74,7 +74,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tmpfs_subr.c,v 1.93 2014/01/03 09:53:12 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tmpfs_subr.c,v 1.94 2014/01/08 16:11:04 pedro Exp $");
 
 #include <sys/param.h>
 #include <sys/cprng.h>
@@ -797,26 +797,26 @@
 tmpfs_dir_getdents(tmpfs_node_t *node, struct uio *uio, off_t *cntp)
 {
        tmpfs_dirent_t *de;
-       struct dirent *dentp;
+       struct dirent dent;
        int error = 0;
 
        KASSERT(VOP_ISLOCKED(node->tn_vnode));
        TMPFS_VALIDATE_DIR(node);
 
        /*
-        * Allocate struct dirent and first check for the "." and "..".
+        * First check for the "." and ".." cases.
         * Note: tmpfs_dir_getdotents() will "seek" for us.
         */
-       dentp = kmem_zalloc(sizeof(struct dirent), KM_SLEEP);
+       memset(&dent, 0, sizeof(dent));
 
        if (uio->uio_offset == TMPFS_DIRSEQ_DOT) {
-               if ((error = tmpfs_dir_getdotents(node, dentp, uio)) != 0) {
+               if ((error = tmpfs_dir_getdotents(node, &dent, uio)) != 0) {
                        goto done;
                }
                (*cntp)++;
        }
        if (uio->uio_offset == TMPFS_DIRSEQ_DOTDOT) {
-               if ((error = tmpfs_dir_getdotents(node, dentp, uio)) != 0) {
+               if ((error = tmpfs_dir_getdotents(node, &dent, uio)) != 0) {
                        goto done;
                }
                (*cntp)++;
@@ -840,26 +840,26 @@
         */
        do {
                if (de->td_node == TMPFS_NODE_WHITEOUT) {
-                       dentp->d_fileno = 1;
-                       dentp->d_type = DT_WHT;
+                       dent.d_fileno = 1;
+                       dent.d_type = DT_WHT;
                } else {
-                       dentp->d_fileno = de->td_node->tn_id;
-                       dentp->d_type = vtype2dt(de->td_node->tn_type);
+                       dent.d_fileno = de->td_node->tn_id;
+                       dent.d_type = vtype2dt(de->td_node->tn_type);
                }
-               dentp->d_namlen = de->td_namelen;
-               KASSERT(de->td_namelen < sizeof(dentp->d_name));
-               memcpy(dentp->d_name, de->td_name, de->td_namelen);
-               dentp->d_name[de->td_namelen] = '\0';
-               dentp->d_reclen = _DIRENT_SIZE(dentp);
+               dent.d_namlen = de->td_namelen;
+               KASSERT(de->td_namelen < sizeof(dent.d_name));
+               memcpy(dent.d_name, de->td_name, de->td_namelen);
+               dent.d_name[de->td_namelen] = '\0';
+               dent.d_reclen = _DIRENT_SIZE(&dent);
 
-               if (dentp->d_reclen > uio->uio_resid) {
+               if (dent.d_reclen > uio->uio_resid) {
                        /* Exhausted UIO space. */
                        error = EJUSTRETURN;
                        break;
                }
 
                /* Copy out the directory entry and continue. */
-               error = uiomove(dentp, dentp->d_reclen, uio);
+               error = uiomove(&dent, dent.d_reclen, uio);
                if (error) {
                        break;
                }
@@ -873,7 +873,6 @@
        node->tn_spec.tn_dir.tn_readdir_lastp = de;
 done:
        tmpfs_update(node->tn_vnode, TMPFS_UPDATE_ATIME);
-       kmem_free(dentp, sizeof(struct dirent));
 
        if (error == EJUSTRETURN) {
                /* Exhausted UIO space - just return. */