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Commit 41bdc602 authored by Joakim Tjernlund's avatar Joakim Tjernlund Committed by David Woodhouse
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jffs2: Reduce excessive scan of empty blocks 



Scanning 1024 bytes to see if an EB is empty is a bit much.
Lower it to 256 bytes and make sure the while loop is
optimized.

Signed-off-by: default avatarJoakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 81cfc9f1

fs/jffs2/scan.c

+6 −6
Original line number Diff line number Diff line
@@ -20,7 +20,7 @@ 
#include "summary.h"

#include "debug.h"



#define DEFAULT_EMPTY_SCAN_SIZE 1024

#define DEFAULT_EMPTY_SCAN_SIZE 256



#define noisy_printk(noise, args...) do { \

	if (*(noise)) { \
@@ -435,7 +435,7 @@ static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblo 
				  unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {

	struct jffs2_unknown_node *node;

	struct jffs2_unknown_node crcnode;

	uint32_t ofs, prevofs;

	uint32_t ofs, prevofs, max_ofs;

	uint32_t hdr_crc, buf_ofs, buf_len;

	int err;

	int noise = 0;
@@ -550,12 +550,12 @@ static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblo 


	/* We temporarily use 'ofs' as a pointer into the buffer/jeb */

	ofs = 0;



	/* Scan only 4KiB of 0xFF before declaring it's empty */

	while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)

	max_ofs = EMPTY_SCAN_SIZE(c->sector_size);

	/* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */

	while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)

		ofs += 4;



	if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {

	if (ofs == max_ofs) {

#ifdef CONFIG_JFFS2_FS_WRITEBUFFER

		if (jffs2_cleanmarker_oob(c)) {

			/* scan oob, take care of cleanmarker */