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fs/proc: Introduce list_for_each_table_entry for proc sysctl
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Use the list_for_each_table_entry macro to optimize the scenario
of traverse ctl_table. This make the code neater and easier to
understand.

Suggested-by: Davidlohr Bueso<[email protected]>
Signed-off-by: Meng Tang <[email protected]>
[updated the sysctl_check_table() hunk due to some changes upstream]
Signed-off-by: Luis Chamberlain <[email protected]>
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@imtangmeng @mcgrof
imtangmeng authored and mcgrof committed Apr 21, 2022
1 parent 3c6a4cb commit cb55f27
Showing 1 changed file with 50 additions and 38 deletions.
88 changes: 50 additions & 38 deletions fs/proc/proc_sysctl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,9 @@
#include <linux/kmemleak.h>
#include "internal.h"

#define list_for_each_table_entry(entry, table) \
for ((entry) = (table); (entry)->procname; (entry)++)

static const struct dentry_operations proc_sys_dentry_operations;
static const struct file_operations proc_sys_file_operations;
static const struct inode_operations proc_sys_inode_operations;
Expand Down Expand Up @@ -215,15 +218,19 @@ static void init_header(struct ctl_table_header *head,
INIT_HLIST_HEAD(&head->inodes);
if (node) {
struct ctl_table *entry;
for (entry = table; entry->procname; entry++, node++)

list_for_each_table_entry(entry, table) {
node->header = head;
node++;
}
}
}

static void erase_header(struct ctl_table_header *head)
{
struct ctl_table *entry;
for (entry = head->ctl_table; entry->procname; entry++)

list_for_each_table_entry(entry, head->ctl_table)
erase_entry(head, entry);
}

Expand All @@ -248,7 +255,7 @@ static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
err = insert_links(header);
if (err)
goto fail_links;
for (entry = header->ctl_table; entry->procname; entry++) {
list_for_each_table_entry(entry, header->ctl_table) {
err = insert_entry(header, entry);
if (err)
goto fail;
Expand Down Expand Up @@ -1130,35 +1137,36 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table)

static int sysctl_check_table(const char *path, struct ctl_table *table)
{
struct ctl_table *entry;
int err = 0;
for (; table->procname; table++) {
if (table->child)
err |= sysctl_err(path, table, "Not a file");

if ((table->proc_handler == proc_dostring) ||
(table->proc_handler == proc_dointvec) ||
(table->proc_handler == proc_douintvec) ||
(table->proc_handler == proc_douintvec_minmax) ||
(table->proc_handler == proc_dointvec_minmax) ||
(table->proc_handler == proc_dou8vec_minmax) ||
(table->proc_handler == proc_dointvec_jiffies) ||
(table->proc_handler == proc_dointvec_userhz_jiffies) ||
(table->proc_handler == proc_dointvec_ms_jiffies) ||
(table->proc_handler == proc_doulongvec_minmax) ||
(table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
if (!table->data)
err |= sysctl_err(path, table, "No data");
if (!table->maxlen)
err |= sysctl_err(path, table, "No maxlen");
list_for_each_table_entry(entry, table) {
if (entry->child)
err |= sysctl_err(path, entry, "Not a file");

if ((entry->proc_handler == proc_dostring) ||
(entry->proc_handler == proc_dointvec) ||
(entry->proc_handler == proc_douintvec) ||
(entry->proc_handler == proc_douintvec_minmax) ||
(entry->proc_handler == proc_dointvec_minmax) ||
(entry->proc_handler == proc_dou8vec_minmax) ||
(entry->proc_handler == proc_dointvec_jiffies) ||
(entry->proc_handler == proc_dointvec_userhz_jiffies) ||
(entry->proc_handler == proc_dointvec_ms_jiffies) ||
(entry->proc_handler == proc_doulongvec_minmax) ||
(entry->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
if (!entry->data)
err |= sysctl_err(path, entry, "No data");
if (!entry->maxlen)
err |= sysctl_err(path, entry, "No maxlen");
else
err |= sysctl_check_table_array(path, table);
err |= sysctl_check_table_array(path, entry);
}
if (!table->proc_handler)
err |= sysctl_err(path, table, "No proc_handler");
if (!entry->proc_handler)
err |= sysctl_err(path, entry, "No proc_handler");

if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode)
err |= sysctl_err(path, table, "bogus .mode 0%o",
table->mode);
if ((entry->mode & (S_IRUGO|S_IWUGO)) != entry->mode)
err |= sysctl_err(path, entry, "bogus .mode 0%o",
entry->mode);
}
return err;
}
Expand All @@ -1174,7 +1182,7 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table

name_bytes = 0;
nr_entries = 0;
for (entry = table; entry->procname; entry++) {
list_for_each_table_entry(entry, table) {
nr_entries++;
name_bytes += strlen(entry->procname) + 1;
}
Expand All @@ -1191,14 +1199,16 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table
node = (struct ctl_node *)(links + 1);
link_table = (struct ctl_table *)(node + nr_entries);
link_name = (char *)&link_table[nr_entries + 1];
link = link_table;

for (link = link_table, entry = table; entry->procname; link++, entry++) {
list_for_each_table_entry(entry, table) {
int len = strlen(entry->procname) + 1;
memcpy(link_name, entry->procname, len);
link->procname = link_name;
link->mode = S_IFLNK|S_IRWXUGO;
link->data = link_root;
link_name += len;
link++;
}
init_header(links, dir->header.root, dir->header.set, node, link_table);
links->nreg = nr_entries;
Expand All @@ -1213,7 +1223,7 @@ static bool get_links(struct ctl_dir *dir,
struct ctl_table *entry, *link;

/* Are there links available for every entry in table? */
for (entry = table; entry->procname; entry++) {
list_for_each_table_entry(entry, table) {
const char *procname = entry->procname;
link = find_entry(&head, dir, procname, strlen(procname));
if (!link)
Expand All @@ -1226,7 +1236,7 @@ static bool get_links(struct ctl_dir *dir,
}

/* The checks passed. Increase the registration count on the links */
for (entry = table; entry->procname; entry++) {
list_for_each_table_entry(entry, table) {
const char *procname = entry->procname;
link = find_entry(&head, dir, procname, strlen(procname));
head->nreg++;
Expand Down Expand Up @@ -1329,7 +1339,7 @@ struct ctl_table_header *__register_sysctl_table(
struct ctl_node *node;
int nr_entries = 0;

for (entry = table; entry->procname; entry++)
list_for_each_table_entry(entry, table)
nr_entries++;

header = kzalloc(sizeof(struct ctl_table_header) +
Expand Down Expand Up @@ -1456,7 +1466,7 @@ static int count_subheaders(struct ctl_table *table)
if (!table || !table->procname)
return 1;

for (entry = table; entry->procname; entry++) {
list_for_each_table_entry(entry, table) {
if (entry->child)
nr_subheaders += count_subheaders(entry->child);
else
Expand All @@ -1475,7 +1485,7 @@ static int register_leaf_sysctl_tables(const char *path, char *pos,
int nr_dirs = 0;
int err = -ENOMEM;

for (entry = table; entry->procname; entry++) {
list_for_each_table_entry(entry, table) {
if (entry->child)
nr_dirs++;
else
Expand All @@ -1492,7 +1502,9 @@ static int register_leaf_sysctl_tables(const char *path, char *pos,
goto out;

ctl_table_arg = files;
for (new = files, entry = table; entry->procname; entry++) {
new = files;

list_for_each_table_entry(entry, table) {
if (entry->child)
continue;
*new = *entry;
Expand All @@ -1516,7 +1528,7 @@ static int register_leaf_sysctl_tables(const char *path, char *pos,
}

/* Recurse into the subdirectories. */
for (entry = table; entry->procname; entry++) {
list_for_each_table_entry(entry, table) {
char *child_pos;

if (!entry->child)
Expand Down Expand Up @@ -1670,7 +1682,7 @@ static void put_links(struct ctl_table_header *header)
if (IS_ERR(core_parent))
return;

for (entry = header->ctl_table; entry->procname; entry++) {
list_for_each_table_entry(entry, header->ctl_table) {
struct ctl_table_header *link_head;
struct ctl_table *link;
const char *name = entry->procname;
Expand Down

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