diff mbox series

mm/damon/dbgfs: remove unnecessary variables

Message ID 20211013130901.1017-1-rongwei.wang@linux.alibaba.com (mailing list archive)
State New
Headers show
Series mm/damon/dbgfs: remove unnecessary variables | expand

Commit Message

Rongwei Wang Oct. 13, 2021, 1:09 p.m. UTC 
In some functions, it's unnecessary to declare 'err'
and 'ret' variables at the same time. This patch mainly
to simplify the issue of such declarations by reusing
one variable.

Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
---
 mm/damon/dbgfs.c | 67 ++++++++++++++++++++++--------------------------
 1 file changed, 31 insertions(+), 36 deletions(-)

Comments

SeongJae Park Oct. 13, 2021, 3:04 p.m. UTC | #1 
Hi Rongwei,


Thank you for this patch!  Looks good to me overall.  I left a couple of
nitpicks below, though.

On Wed, 13 Oct 2021 21:09:01 +0800 Rongwei Wang <rongwei.wang@linux.alibaba.com> wrote:

[...]
> @@ -352,7 +350,7 @@ static ssize_t dbgfs_target_ids_write(struct file *file,
>  
>  	nrs = kbuf;
>  
> -	targets = str_to_target_ids(nrs, ret, &nr_targets);
> +	targets = str_to_target_ids(nrs, count, &nr_targets);
>  	if (!targets) {
>  		ret = -ENOMEM;
>  		goto out;
> @@ -378,12 +376,12 @@ static ssize_t dbgfs_target_ids_write(struct file *file,
>  		goto unlock_out;
>  	}
>  
> -	err = damon_set_targets(ctx, targets, nr_targets);
> -	if (err) {
> +	ret = damon_set_targets(ctx, targets, nr_targets);
> +	if (ret < 0) {

I'd prefer 'if (ret) {', to be consistent with other part.

>  		if (targetid_is_pid(ctx))
>  			dbgfs_put_pids(targets, nr_targets);
> -		ret = err;
> -	}
> +	} else
> +		ret = count;

I'd prefer this to have braces:
https://docs.kernel.org/process/coding-style.html#placing-braces-and-spaces

>  
>  unlock_out:
>  	mutex_unlock(&ctx->kdamond_lock);
> @@ -548,8 +546,7 @@ static ssize_t dbgfs_mk_context_write(struct file *file,
[...]


Thanks,
SJ
Rongwei Wang Oct. 13, 2021, 4:27 p.m. UTC | #2 
On 10/13/21 11:04 PM, SeongJae Park wrote:
> Hi Rongwei,
> 
> 
> Thank you for this patch!  Looks good to me overall.  I left a couple of
> nitpicks below, though.
> 
> On Wed, 13 Oct 2021 21:09:01 +0800 Rongwei Wang <rongwei.wang@linux.alibaba.com> wrote:
> 
> [...]
>> @@ -352,7 +350,7 @@ static ssize_t dbgfs_target_ids_write(struct file *file,
>>   
>>   	nrs = kbuf;
>>   
>> -	targets = str_to_target_ids(nrs, ret, &nr_targets);
>> +	targets = str_to_target_ids(nrs, count, &nr_targets);
>>   	if (!targets) {
>>   		ret = -ENOMEM;
>>   		goto out;
>> @@ -378,12 +376,12 @@ static ssize_t dbgfs_target_ids_write(struct file *file,
>>   		goto unlock_out;
>>   	}
>>   
>> -	err = damon_set_targets(ctx, targets, nr_targets);
>> -	if (err) {
>> +	ret = damon_set_targets(ctx, targets, nr_targets);
>> +	if (ret < 0) {
> 
> I'd prefer 'if (ret) {', to be consistent with other part.
Hi

In fact, explicit style, such as 'if (ret < 0)', may be more 
understandable. But I agree with your advice that to be consistent
with other part. And I will update it like your said.
> 
>>   		if (targetid_is_pid(ctx))
>>   			dbgfs_put_pids(targets, nr_targets);
>> -		ret = err;
>> -	}
>> +	} else
>> +		ret = count;
> 
> I'd prefer this to have braces:
> https://docs.kernel.org/process/coding-style.html#placing-braces-and-spaces
Agree! I will update here.

Thanks!
> 
>>   
>>   unlock_out:
>>   	mutex_unlock(&ctx->kdamond_lock);
>> @@ -548,8 +546,7 @@ static ssize_t dbgfs_mk_context_write(struct file *file,
> [...]
> 
> 
> Thanks,
> SJ
>
diff mbox series

Patch

diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index 28d6abf27763..d8dd68f72827 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -69,8 +69,7 @@  static ssize_t dbgfs_attrs_write(struct file *file,
 	struct damon_ctx *ctx = file->private_data;
 	unsigned long s, a, r, minr, maxr;
 	char *kbuf;
-	ssize_t ret = count;
-	int err;
+	ssize_t ret;
 
 	kbuf = user_input_str(buf, count, ppos);
 	if (IS_ERR(kbuf))
@@ -88,9 +87,9 @@  static ssize_t dbgfs_attrs_write(struct file *file,
 		goto unlock_out;
 	}
 
-	err = damon_set_attrs(ctx, s, a, r, minr, maxr);
-	if (err)
-		ret = err;
+	ret = damon_set_attrs(ctx, s, a, r, minr, maxr);
+	if (!ret)
+		ret = count;
 unlock_out:
 	mutex_unlock(&ctx->kdamond_lock);
 out:
@@ -220,14 +219,13 @@  static ssize_t dbgfs_schemes_write(struct file *file, const char __user *buf,
 	struct damon_ctx *ctx = file->private_data;
 	char *kbuf;
 	struct damos **schemes;
-	ssize_t nr_schemes = 0, ret = count;
-	int err;
+	ssize_t nr_schemes = 0, ret;
 
 	kbuf = user_input_str(buf, count, ppos);
 	if (IS_ERR(kbuf))
 		return PTR_ERR(kbuf);
 
-	schemes = str_to_schemes(kbuf, ret, &nr_schemes);
+	schemes = str_to_schemes(kbuf, count, &nr_schemes);
 	if (!schemes) {
 		ret = -EINVAL;
 		goto out;
@@ -239,11 +237,12 @@  static ssize_t dbgfs_schemes_write(struct file *file, const char __user *buf,
 		goto unlock_out;
 	}
 
-	err = damon_set_schemes(ctx, schemes, nr_schemes);
-	if (err)
-		ret = err;
-	else
+	ret = damon_set_schemes(ctx, schemes, nr_schemes);
+	if (!ret) {
+		ret = count;
 		nr_schemes = 0;
+	}
+
 unlock_out:
 	mutex_unlock(&ctx->kdamond_lock);
 	free_schemes_arr(schemes, nr_schemes);
@@ -342,9 +341,8 @@  static ssize_t dbgfs_target_ids_write(struct file *file,
 	char *kbuf, *nrs;
 	unsigned long *targets;
 	ssize_t nr_targets;
-	ssize_t ret = count;
+	ssize_t ret;
 	int i;
-	int err;
 
 	kbuf = user_input_str(buf, count, ppos);
 	if (IS_ERR(kbuf))
@@ -352,7 +350,7 @@  static ssize_t dbgfs_target_ids_write(struct file *file,
 
 	nrs = kbuf;
 
-	targets = str_to_target_ids(nrs, ret, &nr_targets);
+	targets = str_to_target_ids(nrs, count, &nr_targets);
 	if (!targets) {
 		ret = -ENOMEM;
 		goto out;
@@ -378,12 +376,12 @@  static ssize_t dbgfs_target_ids_write(struct file *file,
 		goto unlock_out;
 	}
 
-	err = damon_set_targets(ctx, targets, nr_targets);
-	if (err) {
+	ret = damon_set_targets(ctx, targets, nr_targets);
+	if (ret < 0) {
 		if (targetid_is_pid(ctx))
 			dbgfs_put_pids(targets, nr_targets);
-		ret = err;
-	}
+	} else
+		ret = count;
 
 unlock_out:
 	mutex_unlock(&ctx->kdamond_lock);
@@ -548,8 +546,7 @@  static ssize_t dbgfs_mk_context_write(struct file *file,
 {
 	char *kbuf;
 	char *ctx_name;
-	ssize_t ret = count;
-	int err;
+	ssize_t ret;
 
 	kbuf = user_input_str(buf, count, ppos);
 	if (IS_ERR(kbuf))
@@ -567,9 +564,9 @@  static ssize_t dbgfs_mk_context_write(struct file *file,
 	}
 
 	mutex_lock(&damon_dbgfs_lock);
-	err = dbgfs_mk_context(ctx_name);
-	if (err)
-		ret = err;
+	ret = dbgfs_mk_context(ctx_name);
+	if (!ret)
+		ret = count;
 	mutex_unlock(&damon_dbgfs_lock);
 
 out:
@@ -638,8 +635,7 @@  static ssize_t dbgfs_rm_context_write(struct file *file,
 		const char __user *buf, size_t count, loff_t *ppos)
 {
 	char *kbuf;
-	ssize_t ret = count;
-	int err;
+	ssize_t ret;
 	char *ctx_name;
 
 	kbuf = user_input_str(buf, count, ppos);
@@ -658,9 +654,9 @@  static ssize_t dbgfs_rm_context_write(struct file *file,
 	}
 
 	mutex_lock(&damon_dbgfs_lock);
-	err = dbgfs_rm_context(ctx_name);
-	if (err)
-		ret = err;
+	ret = dbgfs_rm_context(ctx_name);
+	if (!ret)
+		ret = count;
 	mutex_unlock(&damon_dbgfs_lock);
 
 out:
@@ -684,9 +680,8 @@  static ssize_t dbgfs_monitor_on_read(struct file *file,
 static ssize_t dbgfs_monitor_on_write(struct file *file,
 		const char __user *buf, size_t count, loff_t *ppos)
 {
-	ssize_t ret = count;
+	ssize_t ret;
 	char *kbuf;
-	int err;
 
 	kbuf = user_input_str(buf, count, ppos);
 	if (IS_ERR(kbuf))
@@ -699,14 +694,14 @@  static ssize_t dbgfs_monitor_on_write(struct file *file,
 	}
 
 	if (!strncmp(kbuf, "on", count))
-		err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs);
+		ret = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs);
 	else if (!strncmp(kbuf, "off", count))
-		err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
+		ret = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
 	else
-		err = -EINVAL;
+		ret = -EINVAL;
 
-	if (err)
-		ret = err;
+	if (!ret)
+		ret = count;
 	kfree(kbuf);
 	return ret;
 }