[PATCH linux-next v2] zram: use sysfs_emit() to instead of scnprintf()

[PATCH linux-next v2] zram: use sysfs_emit() to instead of scnprintf()

[yang.yang29]

From: Xu Panda <xu.panda@zte.com.cn>

Replace the open-code with sysfs_emit() to simplify the code.
---
change for v2
 - realign params of sysfs_emit().
---

Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
Signed-off-by: Yang Yang <yang.yang29@zte.com>
---
 drivers/block/zram/zram_drv.c | 61 ++++++++++++++++++++-----------------------
 1 file changed, 28 insertions(+), 33 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9d33801e8ba8..251a142a1f0e 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -255,7 +255,7 @@ static ssize_t initstate_show(struct device *dev,
 	val = init_done(zram);
 	up_read(&zram->init_lock);

-	return scnprintf(buf, PAGE_SIZE, "%u\n", val);
+	return sysfs_emit(buf, "%u\n", val);
 }

 static ssize_t disksize_show(struct device *dev,
@@ -263,7 +263,7 @@ static ssize_t disksize_show(struct device *dev,
 {
 	struct zram *zram = dev_to_zram(dev);

-	return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize);
+	return sysfs_emit(buf, "%llu\n", zram->disksize);
 }

 static ssize_t mem_limit_store(struct device *dev,
@@ -404,7 +404,7 @@ static ssize_t writeback_limit_enable_show(struct device *dev,
 	spin_unlock(&zram->wb_limit_lock);
 	up_read(&zram->init_lock);

-	return scnprintf(buf, PAGE_SIZE, "%d\n", val);
+	return sysfs_emit(buf, "%d\n", val);
 }

 static ssize_t writeback_limit_store(struct device *dev,
@@ -439,7 +439,7 @@ static ssize_t writeback_limit_show(struct device *dev,
 	spin_unlock(&zram->wb_limit_lock);
 	up_read(&zram->init_lock);

-	return scnprintf(buf, PAGE_SIZE, "%llu\n", val);
+	return sysfs_emit(buf, "%llu\n", val);
 }

 static void reset_bdev(struct zram *zram)
@@ -1020,7 +1020,7 @@ static void zram_debugfs_unregister(struct zram *zram) {};
 static ssize_t max_comp_streams_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
-	return scnprintf(buf, PAGE_SIZE, "%d\n", num_online_cpus());
+	return sysfs_emit(buf, "%d\n", num_online_cpus());
 }

 static ssize_t max_comp_streams_store(struct device *dev,
@@ -1191,12 +1191,11 @@ static ssize_t io_stat_show(struct device *dev,
 	ssize_t ret;

 	down_read(&zram->init_lock);
-	ret = scnprintf(buf, PAGE_SIZE,
-			"%8llu %8llu %8llu %8llu\n",
-			(u64)atomic64_read(&zram->stats.failed_reads),
-			(u64)atomic64_read(&zram->stats.failed_writes),
-			(u64)atomic64_read(&zram->stats.invalid_io),
-			(u64)atomic64_read(&zram->stats.notify_free));
+	ret = sysfs_emit(buf, "%8llu %8llu %8llu %8llu\n",
+			 (u64)atomic64_read(&zram->stats.failed_reads),
+			 (u64)atomic64_read(&zram->stats.failed_writes),
+			 (u64)atomic64_read(&zram->stats.invalid_io),
+			 (u64)atomic64_read(&zram->stats.notify_free));
 	up_read(&zram->init_lock);

 	return ret;
@@ -1222,17 +1221,16 @@ static ssize_t mm_stat_show(struct device *dev,
 	orig_size = atomic64_read(&zram->stats.pages_stored);
 	max_used = atomic_long_read(&zram->stats.max_used_pages);

-	ret = scnprintf(buf, PAGE_SIZE,
-			"%8llu %8llu %8llu %8lu %8ld %8llu %8lu %8llu %8llu\n",
-			orig_size << PAGE_SHIFT,
-			(u64)atomic64_read(&zram->stats.compr_data_size),
-			mem_used << PAGE_SHIFT,
-			zram->limit_pages << PAGE_SHIFT,
-			max_used << PAGE_SHIFT,
-			(u64)atomic64_read(&zram->stats.same_pages),
-			atomic_long_read(&pool_stats.pages_compacted),
-			(u64)atomic64_read(&zram->stats.huge_pages),
-			(u64)atomic64_read(&zram->stats.huge_pages_since));
+	ret = sysfs_emit(buf, "%8llu %8llu %8llu %8lu %8ld %8llu %8lu %8llu %8llu\n",
+			 orig_size << PAGE_SHIFT,
+			 (u64)atomic64_read(&zram->stats.compr_data_size),
+			 mem_used << PAGE_SHIFT,
+			 zram->limit_pages << PAGE_SHIFT,
+			 max_used << PAGE_SHIFT,
+			 (u64)atomic64_read(&zram->stats.same_pages),
+			 atomic_long_read(&pool_stats.pages_compacted),
+			 (u64)atomic64_read(&zram->stats.huge_pages),
+			 (u64)atomic64_read(&zram->stats.huge_pages_since));
 	up_read(&zram->init_lock);

 	return ret;
@@ -1247,11 +1245,10 @@ static ssize_t bd_stat_show(struct device *dev,
 	ssize_t ret;

 	down_read(&zram->init_lock);
-	ret = scnprintf(buf, PAGE_SIZE,
-		"%8llu %8llu %8llu\n",
-			FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
-			FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)),
-			FOUR_K((u64)atomic64_read(&zram->stats.bd_writes)));
+	ret = sysfs_emit(buf, "%8llu %8llu %8llu\n",
+			 FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
+			 FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)),
+			 FOUR_K((u64)atomic64_read(&zram->stats.bd_writes)));
 	up_read(&zram->init_lock);

 	return ret;
@@ -1266,11 +1263,9 @@ static ssize_t debug_stat_show(struct device *dev,
 	ssize_t ret;

 	down_read(&zram->init_lock);
-	ret = scnprintf(buf, PAGE_SIZE,
-			"version: %d\n%8llu %8llu\n",
-			version,
-			(u64)atomic64_read(&zram->stats.writestall),
-			(u64)atomic64_read(&zram->stats.miss_free));
+	ret = sysfs_emit(buf, "version: %d\n%8llu %8llu\n", version,
+			 (u64)atomic64_read(&zram->stats.writestall),
+			 (u64)atomic64_read(&zram->stats.miss_free));
 	up_read(&zram->init_lock);

 	return ret;
@@ -2504,7 +2499,7 @@ static ssize_t hot_add_show(struct class *class,

 	if (ret < 0)
 		return ret;
-	return scnprintf(buf, PAGE_SIZE, "%d\n", ret);
+	return sysfs_emit(buf, "%d\n", ret);
 }
 static struct class_attribute class_attr_hot_add =
 	__ATTR(hot_add, 0400, hot_add_show, NULL);
-- 
2.15.2

Re: [PATCH linux-next v2] zram: use sysfs_emit() to instead of scnprintf()

[Minchan Kim]

Hi,

On Tue, Nov 15, 2022 at 08:04:47PM +0800, yang.yang29@zte.com.cn wrote:
> From: Xu Panda <xu.panda@zte.com.cn>
> 
> Replace the open-code with sysfs_emit() to simplify the code.
> ---
> change for v2
>  - realign params of sysfs_emit().
> ---
> 
> Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
> Signed-off-by: Yang Yang <yang.yang29@zte.com>

Recently, we added one more stat is using the scnprintf in mm-unstable
tree? recomp_algorithm_show 

Could you also change it?

Thanks!