[patch 238/262] mm/damon/dbgfs: remove unnecessary variables

Andrew Morton
2021-11-05T20:47:27Z

From: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Subject: mm/damon/dbgfs: remove unnecessary variables

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.

Link: https://lkml.kernel.org/r/20211014073014.35754-1-sj@kernel.org
Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

mm/damon/dbgfs.c | 66 +++++++++++++++++++++------------------------
1 file changed, 31 insertions(+), 35 deletions(-)

--- a/mm/damon/dbgfs.c~mm-damon-dbgfs-remove-unnecessary-variables
+++ a/mm/damon/dbgfs.c
@@ -69,8 +69,7 @@ static ssize_t dbgfs_attrs_write(struct
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
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(struc
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(struc
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);
@@ -343,9 +342,8 @@ static ssize_t dbgfs_target_ids_write(st
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))
@@ -358,7 +356,7 @@ static ssize_t dbgfs_target_ids_write(st
scnprintf(kbuf, count, "42 ");
}

- targets = str_to_target_ids(nrs, ret, &nr_targets);
+ targets = str_to_target_ids(nrs, count, &nr_targets);
if (!targets) {
ret = -ENOMEM;
goto out;
@@ -393,11 +391,12 @@ static ssize_t dbgfs_target_ids_write(st
else
damon_pa_set_primitives(ctx);

- err = damon_set_targets(ctx, targets, nr_targets);
- if (err) {
+ ret = damon_set_targets(ctx, targets, nr_targets);
+ if (ret) {
if (id_is_pid)
dbgfs_put_pids(targets, nr_targets);
- ret = err;
+ } else {
+ ret = count;
}

unlock_out:
@@ -715,8 +714,7 @@ static ssize_t dbgfs_mk_context_write(st
{
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))
@@ -734,9 +732,9 @@ static ssize_t dbgfs_mk_context_write(st
}

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:
@@ -805,8 +803,7 @@ static ssize_t dbgfs_rm_context_write(st
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);
@@ -825,9 +822,9 @@ static ssize_t dbgfs_rm_context_write(st
}

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:
@@ -851,9 +848,8 @@ static ssize_t dbgfs_monitor_on_read(str
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))
@@ -866,14 +862,14 @@ static ssize_t dbgfs_monitor_on_write(st
}

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;
}
_