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Message-Id: <1327674295-3700-2-git-send-email-akinobu.mita@gmail.com>
Date: Fri, 27 Jan 2012 23:24:49 +0900
From: Akinobu Mita <akinobu.mita@...il.com>
To: linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Cc: Akinobu Mita <akinobu.mita@...il.com>,
Jiandong Zheng <jdzheng@...adcom.com>,
Scott Branden <sbranden@...adcom.com>,
David Woodhouse <dwmw2@...radead.org>,
linux-mtd@...ts.infradead.org
Subject: [PATCH] mtd/nand: use string library
- Use memchr_inv to check if the data contains all 0xFF bytes.
It is faster than looping for each byte.
- Use memcmp to compare memory areas
Signed-off-by: Akinobu Mita <akinobu.mita@...il.com>
Cc: Jiandong Zheng <jdzheng@...adcom.com>
Cc: Scott Branden <sbranden@...adcom.com>
Cc: David Woodhouse <dwmw2@...radead.org>
Cc: linux-mtd@...ts.infradead.org
---
drivers/mtd/nand/davinci_nand.c | 7 +++----
drivers/mtd/nand/denali.c | 7 +++----
drivers/mtd/nand/diskonchip.c | 18 +++---------------
drivers/mtd/nand/nand_bbt.c | 16 +++++-----------
drivers/mtd/nand/nand_bcm_umi.c | 10 +++-------
5 files changed, 17 insertions(+), 41 deletions(-)
diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
index 6e56615..423a7cc 100644
--- a/drivers/mtd/nand/davinci_nand.c
+++ b/drivers/mtd/nand/davinci_nand.c
@@ -315,10 +315,9 @@ static int nand_davinci_correct_4bit(struct mtd_info *mtd,
unsigned long timeo;
/* All bytes 0xff? It's an erased page; ignore its ECC. */
- for (i = 0; i < 10; i++) {
- if (ecc_code[i] != 0xff)
- goto compare;
- }
+ if (memchr_inv(ecc_code, 0xff, 10))
+ goto compare;
+
return 0;
compare:
diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
index 3984d48..a87e3a4 100644
--- a/drivers/mtd/nand/denali.c
+++ b/drivers/mtd/nand/denali.c
@@ -908,10 +908,9 @@ static void read_oob_data(struct mtd_info *mtd, uint8_t *buf, int page)
*/
bool is_erased(uint8_t *buf, int len)
{
- int i = 0;
- for (i = 0; i < len; i++)
- if (buf[i] != 0xFF)
- return false;
+ if (memchr_inv(buf, 0xFF, len))
+ return false;
+
return true;
}
#define ECC_SECTOR_SIZE 512
diff --git a/drivers/mtd/nand/diskonchip.c b/drivers/mtd/nand/diskonchip.c
index df921e7..bf0602e 100644
--- a/drivers/mtd/nand/diskonchip.c
+++ b/drivers/mtd/nand/diskonchip.c
@@ -945,12 +945,8 @@ static int doc200x_calculate_ecc(struct mtd_info *mtd, const u_char *dat, unsign
/* Note: this somewhat expensive test should not be triggered
often. It could be optimized away by examining the data in
the writebuf routine, and remembering the result. */
- for (i = 0; i < 512; i++) {
- if (dat[i] == 0xff)
- continue;
+ if (memchr_inv(dat, 0xff, 512))
emptymatch = 0;
- break;
- }
}
/* If emptymatch still =1, we do have an all-0xff data buffer.
Return all-0xff ecc value instead of the computed one, so
@@ -1000,24 +996,16 @@ static int doc200x_correct_data(struct mtd_info *mtd, u_char *dat,
/* If emptymatch=1, the read syndrome is consistent with an
all-0xff data and stored ecc block. Check the stored ecc. */
if (emptymatch) {
- for (i = 0; i < 6; i++) {
- if (read_ecc[i] == 0xff)
- continue;
+ if (memchr_inv(read_ecc, 0xff, 6))
emptymatch = 0;
- break;
- }
}
/* If emptymatch still =1, check the data block. */
if (emptymatch) {
/* Note: this somewhat expensive test should not be triggered
often. It could be optimized away by examining the data in
the readbuf routine, and remembering the result. */
- for (i = 0; i < 512; i++) {
- if (dat[i] == 0xff)
- continue;
+ if (memchr_inv(dat, 0xff, 512))
emptymatch = 0;
- break;
- }
}
/* If emptymatch still =1, this is almost certainly a freshly-
erased block, in which case the ECC will not come out right.
diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
index 20a112f..a1b2dd5 100644
--- a/drivers/mtd/nand/nand_bbt.c
+++ b/drivers/mtd/nand/nand_bbt.c
@@ -100,10 +100,8 @@ static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_desc
end = paglen + td->offs;
if (td->options & NAND_BBT_SCANEMPTY) {
- for (i = 0; i < end; i++) {
- if (p[i] != 0xff)
- return -1;
- }
+ if (memchr_inv(p, 0xff, end))
+ return -1;
}
p += end;
@@ -133,14 +131,10 @@ static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_desc
*/
static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
{
- int i;
- uint8_t *p = buf;
-
/* Compare the pattern */
- for (i = 0; i < td->len; i++) {
- if (p[td->offs + i] != td->pattern[i])
- return -1;
- }
+ if (memcmp(buf + td->offs, td->pattern, td->len))
+ return -1;
+
return 0;
}
diff --git a/drivers/mtd/nand/nand_bcm_umi.c b/drivers/mtd/nand/nand_bcm_umi.c
index 46a6bc9..ad51dad 100644
--- a/drivers/mtd/nand/nand_bcm_umi.c
+++ b/drivers/mtd/nand/nand_bcm_umi.c
@@ -109,13 +109,9 @@ int nand_bcm_umi_bch_correct_page(uint8_t *datap, uint8_t *readEccData,
* see if errors are correctible
*/
if ((regValue & REG_UMI_BCH_CTRL_STATUS_UNCORR_ERR) > 0) {
- int i;
-
- for (i = 0; i < numEccBytes; i++) {
- if (readEccData[i] != 0xff) {
- /* errors cannot be fixed, return -1 */
- return -1;
- }
+ if (memchr_inv(readEccData, 0xff, numEccBytes)) {
+ /* errors cannot be fixed, return -1 */
+ return -1;
}
/* If ECC is unprogrammed then we can't correct,
* assume everything OK */
--
1.7.4.4
--
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