mtd: core: Convert sysfs sprintf/snprintf family to sysfs_emit

Use sysfs_emit instead of snprintf to avoid buf overrun,because in
sysfs_emit it strictly checks whether buf is null or buf whether
pagesize aligned, otherwise it returns an error.
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/1618220144-33839-2-git-send-email-tiantao6@hisilicon.com

drivers/mtd/mtdcore.c

@@ -131,7 +131,7 @@ static ssize_t mtd_type_show(struct device *dev,
 		type = "unknown";
 	}
 
-	return snprintf(buf, PAGE_SIZE, "%s\n", type);
+	return sysfs_emit(buf, "%s\n", type);
 }
 static DEVICE_ATTR(type, S_IRUGO, mtd_type_show, NULL);
 
@@ -140,7 +140,7 @@ static ssize_t mtd_flags_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)mtd->flags);
+	return sysfs_emit(buf, "0x%lx\n", (unsigned long)mtd->flags);
 }
 static DEVICE_ATTR(flags, S_IRUGO, mtd_flags_show, NULL);
 
@@ -149,8 +149,7 @@ static ssize_t mtd_size_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%llu\n",
-		(unsigned long long)mtd->size);
+	return sysfs_emit(buf, "%llu\n", (unsigned long long)mtd->size);
 }
 static DEVICE_ATTR(size, S_IRUGO, mtd_size_show, NULL);
 
@@ -159,7 +158,7 @@ static ssize_t mtd_erasesize_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->erasesize);
+	return sysfs_emit(buf, "%lu\n", (unsigned long)mtd->erasesize);
 }
 static DEVICE_ATTR(erasesize, S_IRUGO, mtd_erasesize_show, NULL);
 
@@ -168,7 +167,7 @@ static ssize_t mtd_writesize_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->writesize);
+	return sysfs_emit(buf, "%lu\n", (unsigned long)mtd->writesize);
 }
 static DEVICE_ATTR(writesize, S_IRUGO, mtd_writesize_show, NULL);
 
@@ -178,7 +177,7 @@ static ssize_t mtd_subpagesize_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 	unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", subpagesize);
+	return sysfs_emit(buf, "%u\n", subpagesize);
 }
 static DEVICE_ATTR(subpagesize, S_IRUGO, mtd_subpagesize_show, NULL);
 
@@ -187,7 +186,7 @@ static ssize_t mtd_oobsize_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->oobsize);
+	return sysfs_emit(buf, "%lu\n", (unsigned long)mtd->oobsize);
 }
 static DEVICE_ATTR(oobsize, S_IRUGO, mtd_oobsize_show, NULL);
 
@@ -196,7 +195,7 @@ static ssize_t mtd_oobavail_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->oobavail);
+	return sysfs_emit(buf, "%u\n", mtd->oobavail);
 }
 static DEVICE_ATTR(oobavail, S_IRUGO, mtd_oobavail_show, NULL);
 
@@ -205,7 +204,7 @@ static ssize_t mtd_numeraseregions_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->numeraseregions);
+	return sysfs_emit(buf, "%u\n", mtd->numeraseregions);
 }
 static DEVICE_ATTR(numeraseregions, S_IRUGO, mtd_numeraseregions_show,
 	NULL);
@@ -215,7 +214,7 @@ static ssize_t mtd_name_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%s\n", mtd->name);
+	return sysfs_emit(buf, "%s\n", mtd->name);
 }
 static DEVICE_ATTR(name, S_IRUGO, mtd_name_show, NULL);
 
@@ -224,7 +223,7 @@ static ssize_t mtd_ecc_strength_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_strength);
+	return sysfs_emit(buf, "%u\n", mtd->ecc_strength);
 }
 static DEVICE_ATTR(ecc_strength, S_IRUGO, mtd_ecc_strength_show, NULL);
 
@@ -234,7 +233,7 @@ static ssize_t mtd_bitflip_threshold_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->bitflip_threshold);
+	return sysfs_emit(buf, "%u\n", mtd->bitflip_threshold);
 }
 
 static ssize_t mtd_bitflip_threshold_store(struct device *dev,
@@ -261,7 +260,7 @@ static ssize_t mtd_ecc_step_size_show(struct device *dev,
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_step_size);
+	return sysfs_emit(buf, "%u\n", mtd->ecc_step_size);
 
 }
 static DEVICE_ATTR(ecc_step_size, S_IRUGO, mtd_ecc_step_size_show, NULL);
@@ -272,7 +271,7 @@ static ssize_t mtd_ecc_stats_corrected_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", ecc_stats->corrected);
+	return sysfs_emit(buf, "%u\n", ecc_stats->corrected);
 }
 static DEVICE_ATTR(corrected_bits, S_IRUGO,
 		   mtd_ecc_stats_corrected_show, NULL);
@@ -283,7 +282,7 @@ static ssize_t mtd_ecc_stats_errors_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", ecc_stats->failed);
+	return sysfs_emit(buf, "%u\n", ecc_stats->failed);
 }
 static DEVICE_ATTR(ecc_failures, S_IRUGO, mtd_ecc_stats_errors_show, NULL);
 
@@ -293,7 +292,7 @@ static ssize_t mtd_badblocks_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", ecc_stats->badblocks);
+	return sysfs_emit(buf, "%u\n", ecc_stats->badblocks);
 }
 static DEVICE_ATTR(bad_blocks, S_IRUGO, mtd_badblocks_show, NULL);
 
@@ -303,7 +302,7 @@ static ssize_t mtd_bbtblocks_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", ecc_stats->bbtblocks);
+	return sysfs_emit(buf, "%u\n", ecc_stats->bbtblocks);
 }
 static DEVICE_ATTR(bbt_blocks, S_IRUGO, mtd_bbtblocks_show, NULL);