cgroup: unify cgroup_write_X64() and cgroup_write_string()
cgroup_write_X64() and cgroup_write_string() both implement about the
same buffering logic. Unify the two into cgroup_file_write() which
always allocates dynamic buffer for simplicity and uses kstrto*()
instead of simple_strto*().
This patch doesn't make any visible behavior changes except for
possibly different error value from kstrsto*().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b132ff9..eb34caf 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2249,90 +2249,50 @@
/* A buffer size big enough for numbers or short strings */
#define CGROUP_LOCAL_BUFFER_SIZE 64
-static ssize_t cgroup_write_X64(struct cgroup_subsys_state *css,
- struct cftype *cft, struct file *file,
- const char __user *userbuf, size_t nbytes,
- loff_t *unused_ppos)
-{
- char buffer[CGROUP_LOCAL_BUFFER_SIZE];
- int retval = 0;
- char *end;
-
- if (!nbytes)
- return -EINVAL;
- if (nbytes >= sizeof(buffer))
- return -E2BIG;
- if (copy_from_user(buffer, userbuf, nbytes))
- return -EFAULT;
-
- buffer[nbytes] = 0; /* nul-terminate */
- if (cft->write_u64) {
- u64 val = simple_strtoull(strstrip(buffer), &end, 0);
- if (*end)
- return -EINVAL;
- retval = cft->write_u64(css, cft, val);
- } else {
- s64 val = simple_strtoll(strstrip(buffer), &end, 0);
- if (*end)
- return -EINVAL;
- retval = cft->write_s64(css, cft, val);
- }
- if (!retval)
- retval = nbytes;
- return retval;
-}
-
-static ssize_t cgroup_write_string(struct cgroup_subsys_state *css,
- struct cftype *cft, struct file *file,
- const char __user *userbuf, size_t nbytes,
- loff_t *unused_ppos)
-{
- char local_buffer[CGROUP_LOCAL_BUFFER_SIZE];
- int retval = 0;
- size_t max_bytes = cft->max_write_len;
- char *buffer = local_buffer;
-
- if (!max_bytes)
- max_bytes = sizeof(local_buffer) - 1;
- if (nbytes >= max_bytes)
- return -E2BIG;
- /* Allocate a dynamic buffer if we need one */
- if (nbytes >= sizeof(local_buffer)) {
- buffer = kmalloc(nbytes + 1, GFP_KERNEL);
- if (buffer == NULL)
- return -ENOMEM;
- }
- if (nbytes && copy_from_user(buffer, userbuf, nbytes)) {
- retval = -EFAULT;
- goto out;
- }
-
- buffer[nbytes] = 0; /* nul-terminate */
- retval = cft->write_string(css, cft, strstrip(buffer));
- if (!retval)
- retval = nbytes;
-out:
- if (buffer != local_buffer)
- kfree(buffer);
- return retval;
-}
-
-static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
+static ssize_t cgroup_file_write(struct file *file, const char __user *userbuf,
size_t nbytes, loff_t *ppos)
{
struct cfent *cfe = __d_cfe(file->f_dentry);
struct cftype *cft = __d_cft(file->f_dentry);
struct cgroup_subsys_state *css = cfe->css;
+ size_t max_bytes = cft->max_write_len ?: CGROUP_LOCAL_BUFFER_SIZE - 1;
+ char *buf;
+ int ret;
- if (cft->write_u64 || cft->write_s64)
- return cgroup_write_X64(css, cft, file, buf, nbytes, ppos);
- if (cft->write_string)
- return cgroup_write_string(css, cft, file, buf, nbytes, ppos);
- if (cft->trigger) {
- int ret = cft->trigger(css, (unsigned int)cft->private);
- return ret ? ret : nbytes;
+ if (nbytes >= max_bytes)
+ return -E2BIG;
+
+ buf = kmalloc(nbytes + 1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ if (copy_from_user(buf, userbuf, nbytes)) {
+ ret = -EFAULT;
+ goto out_free;
}
- return -EINVAL;
+
+ buf[nbytes] = '\0';
+
+ if (cft->write_string) {
+ ret = cft->write_string(css, cft, strstrip(buf));
+ } else if (cft->write_u64) {
+ unsigned long long v;
+ ret = kstrtoull(buf, 0, &v);
+ if (!ret)
+ ret = cft->write_u64(css, cft, v);
+ } else if (cft->write_s64) {
+ long long v;
+ ret = kstrtoll(buf, 0, &v);
+ if (!ret)
+ ret = cft->write_s64(css, cft, v);
+ } else if (cft->trigger) {
+ ret = cft->trigger(css, (unsigned int)cft->private);
+ } else {
+ ret = -EINVAL;
+ }
+out_free:
+ kfree(buf);
+ return ret ?: nbytes;
}
static ssize_t cgroup_read_u64(struct cgroup_subsys_state *css,
