On 19/03/2024 02:17, Christophe JAILLET wrote:

Le 18/03/2024 à 02:28, Li Zhijian a écrit :

quoted

Per filesystems/sysfs.rst, show() should only use sysfs_emit()
or sysfs_emit_at() when formatting the value to be returned to user space.

coccinelle complains that there are still a couple of functions that use
snprintf(). Convert them to sysfs_emit().

scnprintf() will be converted as weel if they have.

Generally, this patch is generated by
make coccicheck M=<path/to/file> MODE=patch \
COCCI=scripts/coccinelle/api/device_attr_show.cocci

No functional change intended

CC: "Bruno Prémont" <bonbons@linux-vserver.org>
CC: Jiri Kosina <jikos@kernel.org>
CC: Benjamin Tissoires <redacted>
CC: linux-input@vger.kernel.org
Signed-off-by: Li Zhijian <redacted>
---
V3:
    Covert more file(drivers/hid/hid-picolcd_fb.c) as suggested by Bruno

This is a part of the work "Fix coccicheck device_attr_show warnings"[1]
Split them per subsystem so that the maintainer can review it easily
[1] https://lore.kernel.org/lkml/20240116041129.3937800-1-lizhijian@fujitsu.com/ (local)
Signed-off-by: Li Zhijian <redacted>
---
  drivers/hid/hid-picolcd_core.c | 6 +++---
  drivers/hid/hid-picolcd_fb.c   | 4 ++--
  2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/hid/hid-picolcd_core.c b/drivers/hid/hid-picolcd_core.c
index bbda231a7ce3..fa46fb6eab3f 100644
--- a/drivers/hid/hid-picolcd_core.c
+++ b/drivers/hid/hid-picolcd_core.c

@@ -256,9 +256,9 @@ static ssize_t picolcd_operation_mode_show(struct device *dev,

      struct picolcd_data *data = dev_get_drvdata(dev);
      if (data->status & PICOLCD_BOOTLOADER)
-        return snprintf(buf, PAGE_SIZE, "[bootloader] lcd\n");
+        return sysfs_emit(buf, "[bootloader] lcd\n");
      else
-        return snprintf(buf, PAGE_SIZE, "bootloader [lcd]\n");
+        return sysfs_emit(buf, "bootloader [lcd]\n");
  }
  static ssize_t picolcd_operation_mode_store(struct device *dev,

@@ -301,7 +301,7 @@ static ssize_t picolcd_operation_mode_delay_show(struct device *dev,

  {
      struct picolcd_data *data = dev_get_drvdata(dev);
-    return snprintf(buf, PAGE_SIZE, "%hu\n", data->opmode_delay);
+    return sysfs_emit(buf, "%hu\n", data->opmode_delay);
  }
  static ssize_t picolcd_operation_mode_delay_store(struct device *dev,

diff --git a/drivers/hid/hid-picolcd_fb.c b/drivers/hid/hid-picolcd_fb.c
index d7dddd99d325..369c78d70e66 100644
--- a/drivers/hid/hid-picolcd_fb.c
+++ b/drivers/hid/hid-picolcd_fb.c

@@ -424,9 +424,9 @@ static ssize_t picolcd_fb_update_rate_show(struct device *dev,

Hi,

just above we have:
     for (i = 1; i <= PICOLCDFB_UPDATE_RATE_LIMIT; i++)

quoted

          if (ret >= PAGE_SIZE)
              break;

and PICOLCDFB_UPDATE_RATE_LIMIT is 10, so it is not possible to have ret >= PAGE_SIZE. Should it happen, sysfs_emit_at() handles it.
So, this test can also be removed, IMHO.

Good catch, i will update it.


Thanks
Zhijian

CJ

quoted

          else if (i == fb_update_rate)
-            ret += scnprintf(buf+ret, PAGE_SIZE-ret, "[%u] ", i);
+            ret += sysfs_emit_at(buf, ret, "[%u] ", i);
          else
-            ret += scnprintf(buf+ret, PAGE_SIZE-ret, "%u ", i);
+            ret += sysfs_emit_at(buf, ret, "%u ", i);
      if (ret > 0)
          buf[min(ret, (size_t)PAGE_SIZE)-1] = '\n';
      return ret;