[JFFS2][XATTR] Remove 'struct list_head ilist' from jffs2_inode_cache.

This patch can reduce 4-byte of memory usage per inode_cache.

[4/10] jffs2-xattr-v5.1-04-remove_ilist_from_ic.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

1 files changed, 47 insertions, 28 deletions

diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
index c9a185c54ce7..b16bc71c9cd2 100644
--- a/fs/jffs2/xattr.c
+++ b/fs/jffs2/xattr.c
@@ -456,7 +456,7 @@ static struct jffs2_xattr_datum *create_xattr_datum(struct jffs2_sb_info *c,
  *   is called to remove xrefs related to obsolete inode when inode is unlinked.
  * jffs2_xattr_free_inode(c, ic)
  *   is called to release xattr related objects when unmounting. 
- * check_xattr_ref_ilist(c, ic)
+ * check_xattr_ref_inode(c, ic)
  *   is used to confirm inode does not have duplicate xattr name/value pair.
  * -------------------------------------------------- */
 static int verify_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
@@ -549,7 +549,6 @@ static void delete_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *re
         BUG_ON(!ref->node);
         delete_xattr_ref_node(c, ref);
 
-        list_del(&ref->ilist);
         xd = ref->xd;
         xd->refcnt--;
         if (!xd->refcnt)
@@ -629,7 +628,8 @@ static struct jffs2_xattr_ref *create_xattr_ref(struct jffs2_sb_info *c, struct
         }
 
         /* Chain to inode */
-        list_add(&ref->ilist, &ic->ilist);
+        ref->next = ic->xref;
+        ic->xref = ref;
 
         return ref; /* success */
 }
@@ -644,8 +644,11 @@ void jffs2_xattr_delete_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache
                 return;
 
         down_write(&c->xattr_sem);
-        list_for_each_entry_safe(ref, _ref, &ic->ilist, ilist)
+        for (ref = ic->xref; ref; ref = _ref) {
+                _ref = ref->next;
                 delete_xattr_ref(c, ref);
+        }
+        ic->xref = NULL;
         up_write(&c->xattr_sem);
 }
 
@@ -656,8 +659,8 @@ void jffs2_xattr_free_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *i
         struct jffs2_xattr_ref *ref, *_ref;
 
         down_write(&c->xattr_sem);
-        list_for_each_entry_safe(ref, _ref, &ic->ilist, ilist) {
-                list_del(&ref->ilist);
+        for (ref = ic->xref; ref; ref = _ref) {
+                _ref = ref->next;
                 xd = ref->xd;
                 xd->refcnt--;
                 if (!xd->refcnt) {
@@ -666,16 +669,17 @@ void jffs2_xattr_free_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *i
                 }
                 jffs2_free_xattr_ref(ref);
         }
+        ic->xref = NULL;
         up_write(&c->xattr_sem);
 }
 
-static int check_xattr_ref_ilist(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
+static int check_xattr_ref_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
 {
-        /* success of check_xattr_ref_ilist() means taht inode (ic) dose not have
+        /* success of check_xattr_ref_inode() means taht inode (ic) dose not have
          * duplicate name/value pairs. If duplicate name/value pair would be found,
          * one will be removed.
          */
-        struct jffs2_xattr_ref *ref, *cmp;
+        struct jffs2_xattr_ref *ref, *cmp, **pref;
         int rc = 0;
 
         if (likely(ic->flags & INO_FLAGS_XATTR_CHECKED))
@@ -683,22 +687,23 @@ static int check_xattr_ref_ilist(struct jffs2_sb_info *c, struct jffs2_inode_cac
         down_write(&c->xattr_sem);
  retry:
         rc = 0;
-        list_for_each_entry(ref, &ic->ilist, ilist) {
+        for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
                 if (!ref->xd->xname) {
                         rc = load_xattr_datum(c, ref->xd);
                         if (unlikely(rc > 0)) {
+                                *pref = ref->next;
                                 delete_xattr_ref(c, ref);
                                 goto retry;
                         } else if (unlikely(rc < 0))
                                 goto out;
                 }
-                cmp = ref;
-                list_for_each_entry_continue(cmp, &ic->ilist, ilist) {
+                for (cmp=ref->next, pref=&ref->next; cmp; pref=&cmp->next, cmp=cmp->next) {
                         if (!cmp->xd->xname) {
                                 ref->xd->flags |= JFFS2_XFLAGS_BIND;
                                 rc = load_xattr_datum(c, cmp->xd);
                                 ref->xd->flags &= ~JFFS2_XFLAGS_BIND;
                                 if (unlikely(rc > 0)) {
+                                        *pref = cmp->next;
                                         delete_xattr_ref(c, cmp);
                                         goto retry;
                                 } else if (unlikely(rc < 0))
@@ -706,6 +711,7 @@ static int check_xattr_ref_ilist(struct jffs2_sb_info *c, struct jffs2_inode_cac
                         }
                         if (ref->xd->xprefix == cmp->xd->xprefix
                             && !strcmp(ref->xd->xname, cmp->xd->xname)) {
+                                *pref = cmp->next;
                                 delete_xattr_ref(c, cmp);
                                 goto retry;
                         }
@@ -736,8 +742,8 @@ void jffs2_init_xattr_subsystem(struct jffs2_sb_info *c)
 
         for (i=0; i < XATTRINDEX_HASHSIZE; i++)
                 INIT_LIST_HEAD(&c->xattrindex[i]);
-        INIT_LIST_HEAD(&c->xattr_temp);
         INIT_LIST_HEAD(&c->xattr_unchecked);
+        c->xref_temp = NULL;
 
         init_rwsem(&c->xattr_sem);
         c->xdatum_mem_usage = 0;
@@ -765,8 +771,11 @@ void jffs2_clear_xattr_subsystem(struct jffs2_sb_info *c)
         struct jffs2_xattr_ref *ref, *_ref;
         int i;
 
-        list_for_each_entry_safe(ref, _ref, &c->xattr_temp, ilist)
+        for (ref=c->xref_temp; ref; ref = _ref) {
+                _ref = ref->next;
                 jffs2_free_xattr_ref(ref);
+        }
+        c->xref_temp = NULL;
 
         for (i=0; i < XATTRINDEX_HASHSIZE; i++) {
                 list_for_each_entry_safe(xd, _xd, &c->xattrindex[i], xindex) {
@@ -788,8 +797,8 @@ void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
         BUG_ON(!(c->flags & JFFS2_SB_FLAG_BUILDING));
 
         /* Phase.1 */
-        list_for_each_entry_safe(ref, _ref, &c->xattr_temp, ilist) {
-                list_del_init(&ref->ilist);
+        for (ref=c->xref_temp; ref; ref=_ref) {
+                _ref = ref->next;
                 /* checking REF_UNCHECKED nodes */
                 if (ref_flags(ref->node) != REF_PRISTINE) {
                         if (verify_xattr_ref(c, ref)) {
@@ -813,9 +822,11 @@ void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
                 ref->xd = xd;
                 ref->ic = ic;
                 xd->refcnt++;
-                list_add_tail(&ref->ilist, &ic->ilist);
+                ref->next = ic->xref;
+                ic->xref = ref;
                 xref_count++;
         }
+        c->xref_temp = NULL;
         /* After this, ref->xid/ino are NEVER used. */
 
         /* Phase.2 */
@@ -931,20 +942,20 @@ ssize_t jffs2_listxattr(struct dentry *dentry, char *buffer, size_t size)
         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
         struct jffs2_inode_cache *ic = f->inocache;
-        struct jffs2_xattr_ref *ref;
+        struct jffs2_xattr_ref *ref, **pref;
         struct jffs2_xattr_datum *xd;
         struct xattr_handler *xhandle;
         ssize_t len, rc;
         int retry = 0;
 
-        rc = check_xattr_ref_ilist(c, ic);
+        rc = check_xattr_ref_inode(c, ic);
         if (unlikely(rc))
                 return rc;
 
         down_read(&c->xattr_sem);
  retry:
         len = 0;
-        list_for_each_entry(ref, &ic->ilist, ilist) {
+        for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
                 BUG_ON(ref->ic != ic);
                 xd = ref->xd;
                 if (!xd->xname) {
@@ -957,6 +968,7 @@ ssize_t jffs2_listxattr(struct dentry *dentry, char *buffer, size_t size)
                         } else {
                                 rc = load_xattr_datum(c, xd);
                                 if (unlikely(rc > 0)) {
+                                        *pref = ref->next;
                                         delete_xattr_ref(c, ref);
                                         goto retry;
                                 } else if (unlikely(rc < 0))
@@ -992,16 +1004,16 @@ int do_jffs2_getxattr(struct inode *inode, int xprefix, const char *xname,
         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
         struct jffs2_inode_cache *ic = f->inocache;
         struct jffs2_xattr_datum *xd;
-        struct jffs2_xattr_ref *ref;
+        struct jffs2_xattr_ref *ref, **pref;
         int rc, retry = 0;
 
-        rc = check_xattr_ref_ilist(c, ic);
+        rc = check_xattr_ref_inode(c, ic);
         if (unlikely(rc))
                 return rc;
 
         down_read(&c->xattr_sem);
  retry:
-        list_for_each_entry(ref, &ic->ilist, ilist) {
+        for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
                 BUG_ON(ref->ic!=ic);
 
                 xd = ref->xd;
@@ -1017,6 +1029,7 @@ int do_jffs2_getxattr(struct inode *inode, int xprefix, const char *xname,
                         } else {
                                 rc = load_xattr_datum(c, xd);
                                 if (unlikely(rc > 0)) {
+                                        *pref = ref->next;
                                         delete_xattr_ref(c, ref);
                                         goto retry;
                                 } else if (unlikely(rc < 0)) {
@@ -1053,11 +1066,11 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
         struct jffs2_inode_cache *ic = f->inocache;
         struct jffs2_xattr_datum *xd;
-        struct jffs2_xattr_ref *ref, *newref;
+        struct jffs2_xattr_ref *ref, *newref, **pref;
         uint32_t phys_ofs, length, request;
         int rc;
 
-        rc = check_xattr_ref_ilist(c, ic);
+        rc = check_xattr_ref_inode(c, ic);
         if (unlikely(rc))
                 return rc;
 
@@ -1072,13 +1085,14 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
         /* Find existing xattr */
         down_write(&c->xattr_sem);
  retry:
-        list_for_each_entry(ref, &ic->ilist, ilist) {
+        for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
                 xd = ref->xd;
                 if (xd->xprefix != xprefix)
                         continue;
                 if (!xd->xname) {
                         rc = load_xattr_datum(c, xd);
                         if (unlikely(rc > 0)) {
+                                *pref = ref->next;
                                 delete_xattr_ref(c, ref);
                                 goto retry;
                         } else if (unlikely(rc < 0))
@@ -1090,6 +1104,7 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
                                 goto out;
                         }
                         if (!buffer) {
+                                *pref = ref->next;
                                 delete_xattr_ref(c, ref);
                                 rc = 0;
                                 goto out;
@@ -1098,7 +1113,6 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
                 }
         }
         /* not found */
-        ref = NULL;
         if (flags & XATTR_REPLACE) {
                 rc = -ENODATA;
                 goto out;
@@ -1130,14 +1144,19 @@ int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
                 return rc;
         }
         down_write(&c->xattr_sem);
+        if (ref)
+                *pref = ref->next;
         newref = create_xattr_ref(c, ic, xd, phys_ofs);
         if (IS_ERR(newref)) {
+                if (ref) {
+                        ref->next = ic->xref;
+                        ic->xref = ref;
+                }
                 rc = PTR_ERR(newref);
                 xd->refcnt--;
                 if (!xd->refcnt)
                         delete_xattr_datum(c, xd);
         } else if (ref) {
-                /* If replaced xattr_ref exists */
                 delete_xattr_ref(c, ref);
         }
  out: