[PATCH] zram: use scnprintf() in attrs show() methods

Sergey Senozhatsky
2014-03-09T19:30:55Z

sysfs.txt documentation lists the following requirements:

- The buffer will always be PAGE_SIZE bytes in length. On i386, this
is 4096.

- show() methods should return the number of bytes printed into the
buffer. This is the return value of scnprintf().

- show() should always use scnprintf().

Use scnprintf() in show() functions.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
drivers/block/zram/zcomp.c | 8 +++++---
drivers/block/zram/zram_drv.c | 12 ++++++------
2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 92a83df..ffcaff7 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -274,12 +274,14 @@ ssize_t zcomp_available_show(const char *comp, char *buf)

while (backends[i]) {
if (sysfs_streq(comp, backends[i]->name))
- sz += sprintf(buf + sz, "[%s] ", backends[i]->name);
+ sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
+ "[%s] ", backends[i]->name);
else
- sz += sprintf(buf + sz, "%s ", backends[i]->name);
+ sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
+ "%s ", backends[i]->name);
i++;
}
- sz += sprintf(buf + sz, "\n");
+ sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
return sz;
}

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 7631ef0..e6ff420 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -47,7 +47,7 @@ static ssize_t zram_attr_##name##_show(struct device *d, \
struct device_attribute *attr, char *b) \
{ \
struct zram *zram = dev_to_zram(d); \
- return sprintf(b, "%llu\n", \
+ return scnprintf(b, PAGE_SIZE, "%llu\n", \
(u64)atomic64_read(&zram->stats.name)); \
} \
static struct device_attribute dev_attr_##name = \
@@ -68,7 +68,7 @@ static ssize_t disksize_show(struct device *dev,
{
struct zram *zram = dev_to_zram(dev);

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

static ssize_t initstate_show(struct device *dev,
@@ -81,7 +81,7 @@ static ssize_t initstate_show(struct device *dev,
val = init_done(zram);
up_read(&zram->init_lock);

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

static ssize_t orig_data_size_show(struct device *dev,
@@ -89,7 +89,7 @@ static ssize_t orig_data_size_show(struct device *dev,
{
struct zram *zram = dev_to_zram(dev);

- return sprintf(buf, "%llu\n",
+ return scnprintf(buf, PAGE_SIZE, "%llu\n",
(u64)(atomic64_read(&zram->stats.pages_stored)) << PAGE_SHIFT);
}

@@ -105,7 +105,7 @@ static ssize_t mem_used_total_show(struct device *dev,
val = zs_get_total_size_bytes(meta->mem_pool);
up_read(&zram->init_lock);

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

static ssize_t max_comp_streams_show(struct device *dev,
@@ -118,7 +118,7 @@ static ssize_t max_comp_streams_show(struct device *dev,
val = zram->max_comp_streams;
up_read(&zram->init_lock);

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

static ssize_t max_comp_streams_store(struct device *dev,
--
1.9.0.477.g83111a0