Disable unused pathname::pn_path* (unneeded in Linux)

struct pathname is originally from Solaris VFS, and it has been used in ZoL to merely call VOP from Linux VFS interface without API change, therefore pathname::pn_path* are unused and unneeded. Technically, struct pathname is a wrapper for C string in ZoL. Saves stack a bit on lookup and unlink. (#if0'd members instead of removing since comments refer to them.) Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Richard Elling <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Tomohiro Kusumi <[email protected]> Closes #9025
openzfs · Sep 25, 2019 · 0a22324 · 0a22324
1 parent cf966cb
commit 0a22324
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Showing 2 changed files with 13 additions and 4 deletions.
diff --git a/include/sys/pathname.h b/include/sys/pathname.h
@@ -54,8 +54,10 @@ extern "C" {
  */
 typedef struct pathname {
 	char	*pn_buf;		/* underlying storage */
+#if 0 /* unused in ZoL */
 	char	*pn_path;		/* remaining pathname */
 	size_t	pn_pathlen;		/* remaining length */
+#endif
 	size_t	pn_bufsize;		/* total size of pn_buf */
 } pathname_t;
 

diff --git a/module/zfs/pathname.c b/module/zfs/pathname.c
@@ -71,9 +71,12 @@ pn_alloc(struct pathname *pnp)
 void
 pn_alloc_sz(struct pathname *pnp, size_t sz)
 {
-	pnp->pn_path = pnp->pn_buf = kmem_alloc(sz, KM_SLEEP);
-	pnp->pn_pathlen = 0;
+	pnp->pn_buf = kmem_alloc(sz, KM_SLEEP);
 	pnp->pn_bufsize = sz;
+#if 0 /* unused in ZoL */
+	pnp->pn_path = pnp->pn_buf;
+	pnp->pn_pathlen = 0;
+#endif
 }
 
 /*
@@ -84,6 +87,10 @@ pn_free(struct pathname *pnp)
 {
 	/* pn_bufsize is usually MAXPATHLEN, but may not be */
 	kmem_free(pnp->pn_buf, pnp->pn_bufsize);
-	pnp->pn_path = pnp->pn_buf = NULL;
-	pnp->pn_pathlen = pnp->pn_bufsize = 0;
+	pnp->pn_buf = NULL;
+	pnp->pn_bufsize = 0;
+#if 0 /* unused in ZoL */
+	pnp->pn_path = NULL;
+	pnp->pn_pathlen = 0;
+#endif
 }