2022-11-15 13:01:13

by Yang Yang

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

From: Xu Panda <[email protected]>

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

Signed-off-by: Xu Panda <[email protected]>
Signed-off-by: Yang Yang <[email protected]>
---
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

2022-11-16 00:15:47

by Minchan Kim

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

Hi,

On Tue, Nov 15, 2022 at 08:04:47PM +0800, [email protected] wrote:
> From: Xu Panda <[email protected]>
>
> Replace the open-code with sysfs_emit() to simplify the code.
> ---
> change for v2
> - realign params of sysfs_emit().
> ---
>
> Signed-off-by: Xu Panda <[email protected]>
> Signed-off-by: Yang Yang <[email protected]>

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

Could you also change it?

Thanks!