[JFFS2] Core changes required to support JFFS2-on-Dataflash devices.

DataFlash page-sizes are not a power of two (they're multiples of 528
bytes).  There are a few places in JFFS2 code where sector_size is used
as a bitmask.  A new macro (SECTOR_ADDR) was defined to calculate these
sector addresses. For non-DataFlash devices, the original (faster)
bitmask operation is still used.

In scan.c, the EMPTY_SCAN_SIZE was a constant of 1024.
Since this could be larger than the sector size of the DataFlash, this
is now basically set to MIN(sector_size, 1024).

Addition of a jffs2_is_writebuffered() macro.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 14 insertions, 6 deletions

diff --git a/fs/jffs2/scan.c b/fs/jffs2/scan.c
index ded53584a897..76859ff53437 100644
--- a/fs/jffs2/scan.c
+++ b/fs/jffs2/scan.c
@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: scan.c,v 1.115 2004/11/17 12:59:08 dedekind Exp $
+ * $Id: scan.c,v 1.116 2005/02/09 09:09:02 pavlov Exp $
  *
  */
 #include <linux/kernel.h>
@@ -19,7 +19,7 @@
 #include <linux/compiler.h>
 #include "nodelist.h"
 
-#define EMPTY_SCAN_SIZE 1024
+#define DEFAULT_EMPTY_SCAN_SIZE 1024
 
 #define DIRTY_SPACE(x) do { typeof(x) _x = (x); \
                 c->free_size -= _x; c->dirty_size += _x; \
@@ -75,6 +75,14 @@ static inline int min_free(struct jffs2_sb_info *c)
         return min;
 
 }
+
+static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
+        if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
+                return sector_size;
+        else
+                return DEFAULT_EMPTY_SCAN_SIZE;
+}
+
 int jffs2_scan_medium(struct jffs2_sb_info *c)
 {
         int i, ret;
@@ -316,7 +324,7 @@ static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblo
         if (!buf_size) {
                 buf_len = c->sector_size;
         } else {
-                buf_len = EMPTY_SCAN_SIZE;
+                buf_len = EMPTY_SCAN_SIZE(c->sector_size);
                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
                 if (err)
                         return err;
@@ -326,10 +334,10 @@ static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblo
         ofs = 0;
 
         /* Scan only 4KiB of 0xFF before declaring it's empty */
-        while(ofs < EMPTY_SCAN_SIZE && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
+        while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
                 ofs += 4;
 
-        if (ofs == EMPTY_SCAN_SIZE) {
+        if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 #ifdef CONFIG_JFFS2_FS_NAND
                 if (jffs2_cleanmarker_oob(c)) {
                         /* scan oob, take care of cleanmarker */
@@ -423,7 +431,7 @@ scan_more:
                            bail now */
                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) && 
                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_in_ino) {
-                                D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE));
+                                D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
                                 return BLK_STATE_CLEANMARKER;
                         }