[PATCH 1/2] firewire: Kill unnecessary buf check in device_attribute.show

Li Zhijian
2024-01-22T05:40:02Z

Per Documentation/filesystems/sysfs.rst:
> sysfs allocates a buffer of size (PAGE_SIZE) and passes it to the
> method.

So we can kill the unnecessary buf check safely.

Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
---
drivers/firewire/core-device.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/drivers/firewire/core-device.c b/drivers/firewire/core-device.c
index 0547253d16fe..47d6cb3dc916 100644
--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -323,7 +323,7 @@ static ssize_t show_immediate(struct device *dev,
if (value < 0)
return -ENOENT;

- return snprintf(buf, buf ? PAGE_SIZE : 0, "0x%06x\n", value);
+ return snprintf(buf, PAGE_SIZE, "0x%06x\n", value);
}

#define IMMEDIATE_ATTR(name, key) \
@@ -335,8 +335,6 @@ static ssize_t show_text_leaf(struct device *dev,
struct config_rom_attribute *attr =
container_of(dattr, struct config_rom_attribute, attr);
const u32 *directories[] = {NULL, NULL};
- size_t bufsize;
- char dummy_buf[2];
int i, ret = -ENOENT;

down_read(&fw_device_rwsem);
@@ -358,15 +356,9 @@ static ssize_t show_text_leaf(struct device *dev,
}
}

- if (buf) {
- bufsize = PAGE_SIZE - 1;
- } else {
- buf = dummy_buf;
- bufsize = 1;
- }
-
for (i = 0; i < ARRAY_SIZE(directories) && !!directories[i]; ++i) {
- int result = fw_csr_string(directories[i], attr->key, buf, bufsize);
+ int result = fw_csr_string(directories[i], attr->key, buf,
+ PAGE_SIZE - 1);
// Detected.
if (result >= 0)
ret = result;
--
2.29.2