JFFS2: Improve speed reading flash files
authorMark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Wed, 1 Jul 2015 04:38:25 +0000 (16:38 +1200)
committerLothar Waßmann <LW@KARO-electronics.de>
Thu, 10 Sep 2015 06:24:12 +0000 (08:24 +0200)
jffs2_1pass_read_inode() would read the entire data for each node
in the filesystem, regardless of whether it was part of the file
to be loaded or not. By only reading the header data for an inode,
and then reading the data only when it is found to be part of the
file to be loaded, much copying of data is saved.

jffs2_1pass_list_inodes() read each inode for every file in the
directory into a buffer. By using NULL as a buffer pointer, NOR
flash simply returns a pointer, and therefore avoids a memory copy.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
fs/jffs2/jffs2_1pass.c

index 346f3a1..e58e7d2 100644 (file)
@@ -735,8 +735,13 @@ jffs2_1pass_read_inode(struct b_lists *pL, u32 inode, char *dest)
 #endif
 
        for (b = pL->frag.listHead; b != NULL; b = b->next) {
-               jNode = (struct jffs2_raw_inode *) get_node_mem(b->offset,
-                                                               pL->readbuf);
+               /*
+                * Copy just the node and not the data at this point,
+                * since we don't yet know if we need this data.
+                */
+               jNode = (struct jffs2_raw_inode *)get_fl_mem(b->offset,
+                               sizeof(struct jffs2_raw_inode),
+                               pL->readbuf);
                if (inode == jNode->ino) {
 #if 0
                        putLabeledWord("\r\n\r\nread_inode: totlen = ", jNode->totlen);
@@ -760,7 +765,15 @@ jffs2_1pass_read_inode(struct b_lists *pL, u32 inode, char *dest)
 #endif
 
                        if(dest) {
-                               src = ((uchar *) jNode) + sizeof(struct jffs2_raw_inode);
+                               /*
+                                * Now that the inode has been checked,
+                                * read the entire inode, including data.
+                                */
+                               put_fl_mem(jNode, pL->readbuf);
+                               jNode = (struct jffs2_raw_inode *)
+                                       get_node_mem(b->offset, pL->readbuf);
+                               src = ((uchar *)jNode) +
+                                       sizeof(struct jffs2_raw_inode);
                                /* ignore data behind latest known EOF */
                                if (jNode->offset > totalSize) {
                                        put_fl_mem(jNode, pL->readbuf);
@@ -967,7 +980,6 @@ jffs2_1pass_list_inodes(struct b_lists * pL, u32 pino)
                                                                pL->readbuf);
                if (pino == jDir->pino) {
                        u32 i_version = 0;
-                       struct jffs2_raw_inode ojNode;
                        struct jffs2_raw_inode *jNode, *i = NULL;
                        struct b_node *b2;
 
@@ -1003,8 +1015,10 @@ jffs2_1pass_list_inodes(struct b_lists * pL, u32 pino)
 
                        for (b2 = pL->frag.listHead; b2; b2 = b2->next) {
                                jNode = (struct jffs2_raw_inode *)
-                                       get_fl_mem(b2->offset, sizeof(ojNode), &ojNode);
-                               if (jNode->ino == jDir->ino && jNode->version >= i_version) {
+                                       get_fl_mem(b2->offset, sizeof(*jNode),
+                                                  NULL);
+                               if (jNode->ino == jDir->ino &&
+                                   jNode->version >= i_version) {
                                        i_version = jNode->version;
                                        if (i)
                                                put_fl_mem(i, NULL);
@@ -1017,6 +1031,7 @@ jffs2_1pass_list_inodes(struct b_lists * pL, u32 pino)
                                                               sizeof(*i),
                                                               NULL);
                                }
+                               put_fl_mem(jNode, NULL);
                        }
 
                        dump_inode(pL, jDir, i);