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authorJoakim Tjernlund <Joakim.Tjernlund@transmode.se>2007-03-27 13:32:09 +0200
committerDavid Woodhouse <dwmw2@infradead.org>2007-04-17 14:07:34 -0400
commitc2aecda79cd872679b9b11f9e59d797fb4c7d677 (patch)
tree3e4faadfeaf51cd849592029f757503008720585 /fs/jffs2
parent10731f83009e2556f98ffa5c7c2cbffe66dacfb3 (diff)
downloadlinux-c2aecda79cd872679b9b11f9e59d797fb4c7d677.tar.gz
[JFFS2] Speed up mount for directly-mapped NOR flash
Remove excessive scanning of empty flash after a clean
marker for users of the point/unpoint method. cfi_cmdset_0001
uses point/unpoint by default iff flash mapping is linear.
The speedup is several orders of magnitude if FS is less than
half full.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Diffstat (limited to 'fs/jffs2')
-rw-r--r--fs/jffs2/scan.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/fs/jffs2/scan.c b/fs/jffs2/scan.c
index a5103df5242e..7a46a436edfc 100644
--- a/fs/jffs2/scan.c
+++ b/fs/jffs2/scan.c
@@ -636,16 +636,17 @@ scan_more:
 
 		if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 			uint32_t inbuf_ofs;
-			uint32_t empty_start;
+			uint32_t empty_start, scan_end;
 
 			empty_start = ofs;
 			ofs += 4;
+			scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 
 			D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 		more_empty:
 			inbuf_ofs = ofs - buf_ofs;
-			while (inbuf_ofs < buf_len) {
-				if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
+			while (inbuf_ofs < scan_end) {
+				if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 					printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 					       empty_start, ofs);
 					if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
@@ -666,7 +667,11 @@ scan_more:
 				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;
 			}
-
+			if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
+				scan_end = buf_len;
+				goto more_empty;
+			}
+			
 			/* See how much more there is to read in this eraseblock... */
 			buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 			if (!buf_len) {
@@ -676,6 +681,8 @@ scan_more:
 					  empty_start));
 				break;
 			}
+			/* point never reaches here */
+			scan_end = buf_len;
 			D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 			err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 			if (err)