quota_tree: Avoid dynamic memory allocations
Most allocations done here are rather small and can fit on the stack, eliminating the need to allocate them dynamically. Reserve a 1024B stack buffer for this purpose to avoid the overhead of dynamic memory allocation. 1024B covers most use cases, and higher values were observed to cause stack corruptions. Co-authored-by: Sultan Alsawaf <sultan@kerneltoast.com> Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
This commit is contained in:
Park Ju Hyung
spakkkk
parent
33ce619f2f
commit
4d8e9a4708
@ -46,14 +46,37 @@ static int qtree_dqstr_in_blk(struct qtree_mem_dqinfo *info)
|
||||
/ info->dqi_entry_size;
|
||||
}
|
||||
|
||||
static char *getdqbuf(size_t size)
|
||||
{
|
||||
char *buf = kmalloc(size, GFP_NOFS);
|
||||
if (!buf)
|
||||
printk(KERN_WARNING
|
||||
"VFS: Not enough memory for quota buffers.\n");
|
||||
return buf;
|
||||
}
|
||||
#define STACK_ALLOC_SIZE SZ_1K
|
||||
#define GETDQBUF_NORET(size) \
|
||||
char *buf; \
|
||||
char buf_onstack[STACK_ALLOC_SIZE] __aligned(8); \
|
||||
if (unlikely(size > STACK_ALLOC_SIZE)) { \
|
||||
buf = kmalloc(size, GFP_NOFS); \
|
||||
if (!buf) \
|
||||
printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n"); \
|
||||
} else { \
|
||||
buf = buf_onstack; \
|
||||
}
|
||||
|
||||
#define __GETDQBUF(size) \
|
||||
if (unlikely(size > STACK_ALLOC_SIZE)) { \
|
||||
buf = kmalloc(size, GFP_NOFS); \
|
||||
if (!buf) { \
|
||||
printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n"); \
|
||||
return -ENOMEM; \
|
||||
} \
|
||||
} else { \
|
||||
buf = buf_onstack; \
|
||||
}
|
||||
|
||||
#define GETDQBUF(size) \
|
||||
char *buf; \
|
||||
char buf_onstack[STACK_ALLOC_SIZE] __aligned(8); \
|
||||
__GETDQBUF(size);
|
||||
|
||||
#define FREEDQBUF() \
|
||||
if (unlikely(buf != buf_onstack)) \
|
||||
kfree(buf);
|
||||
|
||||
static ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
|
||||
{
|
||||
@ -111,12 +134,12 @@ static int check_dquot_block_header(struct qtree_mem_dqinfo *info,
|
||||
/* Remove empty block from list and return it */
|
||||
static int get_free_dqblk(struct qtree_mem_dqinfo *info)
|
||||
{
|
||||
char *buf = getdqbuf(info->dqi_usable_bs);
|
||||
struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
|
||||
struct qt_disk_dqdbheader *dh;
|
||||
int ret, blk;
|
||||
GETDQBUF(info->dqi_usable_bs);
|
||||
|
||||
dh = (struct qt_disk_dqdbheader *)buf;
|
||||
|
||||
if (!buf)
|
||||
return -ENOMEM;
|
||||
if (info->dqi_free_blk) {
|
||||
blk = info->dqi_free_blk;
|
||||
ret = read_blk(info, blk, buf);
|
||||
@ -138,7 +161,7 @@ static int get_free_dqblk(struct qtree_mem_dqinfo *info)
|
||||
mark_info_dirty(info->dqi_sb, info->dqi_type);
|
||||
ret = blk;
|
||||
out_buf:
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return ret;
|
||||
}
|
||||
|
||||
@ -160,83 +183,79 @@ static int put_free_dqblk(struct qtree_mem_dqinfo *info, char *buf, uint blk)
|
||||
}
|
||||
|
||||
/* Remove given block from the list of blocks with free entries */
|
||||
static int remove_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
|
||||
static int remove_free_dqentry(struct qtree_mem_dqinfo *info, char *pbuf,
|
||||
uint blk)
|
||||
{
|
||||
char *tmpbuf = getdqbuf(info->dqi_usable_bs);
|
||||
struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
|
||||
struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)pbuf;
|
||||
uint nextblk = le32_to_cpu(dh->dqdh_next_free);
|
||||
uint prevblk = le32_to_cpu(dh->dqdh_prev_free);
|
||||
int err;
|
||||
GETDQBUF(info->dqi_usable_bs);
|
||||
|
||||
if (!tmpbuf)
|
||||
return -ENOMEM;
|
||||
if (nextblk) {
|
||||
err = read_blk(info, nextblk, tmpbuf);
|
||||
err = read_blk(info, nextblk, buf);
|
||||
if (err < 0)
|
||||
goto out_buf;
|
||||
((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
|
||||
((struct qt_disk_dqdbheader *)buf)->dqdh_prev_free =
|
||||
dh->dqdh_prev_free;
|
||||
err = write_blk(info, nextblk, tmpbuf);
|
||||
err = write_blk(info, nextblk, buf);
|
||||
if (err < 0)
|
||||
goto out_buf;
|
||||
}
|
||||
if (prevblk) {
|
||||
err = read_blk(info, prevblk, tmpbuf);
|
||||
err = read_blk(info, prevblk, buf);
|
||||
if (err < 0)
|
||||
goto out_buf;
|
||||
((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_next_free =
|
||||
((struct qt_disk_dqdbheader *)buf)->dqdh_next_free =
|
||||
dh->dqdh_next_free;
|
||||
err = write_blk(info, prevblk, tmpbuf);
|
||||
err = write_blk(info, prevblk, buf);
|
||||
if (err < 0)
|
||||
goto out_buf;
|
||||
} else {
|
||||
info->dqi_free_entry = nextblk;
|
||||
mark_info_dirty(info->dqi_sb, info->dqi_type);
|
||||
}
|
||||
kfree(tmpbuf);
|
||||
FREEDQBUF();
|
||||
dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
|
||||
/* No matter whether write succeeds block is out of list */
|
||||
if (write_blk(info, blk, buf) < 0)
|
||||
if (write_blk(info, blk, pbuf) < 0)
|
||||
quota_error(info->dqi_sb, "Can't write block (%u) "
|
||||
"with free entries", blk);
|
||||
return 0;
|
||||
out_buf:
|
||||
kfree(tmpbuf);
|
||||
FREEDQBUF();
|
||||
return err;
|
||||
}
|
||||
|
||||
/* Insert given block to the beginning of list with free entries */
|
||||
static int insert_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
|
||||
static int insert_free_dqentry(struct qtree_mem_dqinfo *info, char *pbuf,
|
||||
uint blk)
|
||||
{
|
||||
char *tmpbuf = getdqbuf(info->dqi_usable_bs);
|
||||
struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
|
||||
struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)pbuf;
|
||||
int err;
|
||||
GETDQBUF(info->dqi_usable_bs);
|
||||
|
||||
if (!tmpbuf)
|
||||
return -ENOMEM;
|
||||
dh->dqdh_next_free = cpu_to_le32(info->dqi_free_entry);
|
||||
dh->dqdh_prev_free = cpu_to_le32(0);
|
||||
err = write_blk(info, blk, buf);
|
||||
err = write_blk(info, blk, pbuf);
|
||||
if (err < 0)
|
||||
goto out_buf;
|
||||
if (info->dqi_free_entry) {
|
||||
err = read_blk(info, info->dqi_free_entry, tmpbuf);
|
||||
err = read_blk(info, info->dqi_free_entry, buf);
|
||||
if (err < 0)
|
||||
goto out_buf;
|
||||
((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
|
||||
((struct qt_disk_dqdbheader *)buf)->dqdh_prev_free =
|
||||
cpu_to_le32(blk);
|
||||
err = write_blk(info, info->dqi_free_entry, tmpbuf);
|
||||
err = write_blk(info, info->dqi_free_entry, buf);
|
||||
if (err < 0)
|
||||
goto out_buf;
|
||||
}
|
||||
kfree(tmpbuf);
|
||||
FREEDQBUF();
|
||||
info->dqi_free_entry = blk;
|
||||
mark_info_dirty(info->dqi_sb, info->dqi_type);
|
||||
return 0;
|
||||
out_buf:
|
||||
kfree(tmpbuf);
|
||||
FREEDQBUF();
|
||||
return err;
|
||||
}
|
||||
|
||||
@ -258,11 +277,11 @@ static uint find_free_dqentry(struct qtree_mem_dqinfo *info,
|
||||
{
|
||||
uint blk, i;
|
||||
struct qt_disk_dqdbheader *dh;
|
||||
char *buf = getdqbuf(info->dqi_usable_bs);
|
||||
char *ddquot;
|
||||
GETDQBUF_NORET(info->dqi_usable_bs);
|
||||
|
||||
*err = 0;
|
||||
if (!buf) {
|
||||
if (unlikely((buf != buf_onstack) && !buf)) {
|
||||
*err = -ENOMEM;
|
||||
return 0;
|
||||
}
|
||||
@ -279,7 +298,7 @@ static uint find_free_dqentry(struct qtree_mem_dqinfo *info,
|
||||
blk = get_free_dqblk(info);
|
||||
if ((int)blk < 0) {
|
||||
*err = blk;
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return 0;
|
||||
}
|
||||
memset(buf, 0, info->dqi_usable_bs);
|
||||
@ -321,10 +340,10 @@ static uint find_free_dqentry(struct qtree_mem_dqinfo *info,
|
||||
dquot->dq_off = ((loff_t)blk << info->dqi_blocksize_bits) +
|
||||
sizeof(struct qt_disk_dqdbheader) +
|
||||
i * info->dqi_entry_size;
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return blk;
|
||||
out_buf:
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return 0;
|
||||
}
|
||||
|
||||
@ -332,13 +351,11 @@ out_buf:
|
||||
static int do_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
|
||||
uint *treeblk, int depth)
|
||||
{
|
||||
char *buf = getdqbuf(info->dqi_usable_bs);
|
||||
int ret = 0, newson = 0, newact = 0;
|
||||
__le32 *ref;
|
||||
uint newblk;
|
||||
GETDQBUF(info->dqi_usable_bs);
|
||||
|
||||
if (!buf)
|
||||
return -ENOMEM;
|
||||
if (!*treeblk) {
|
||||
ret = get_free_dqblk(info);
|
||||
if (ret < 0)
|
||||
@ -381,7 +398,7 @@ static int do_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
|
||||
put_free_dqblk(info, buf, *treeblk);
|
||||
}
|
||||
out_buf:
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return ret;
|
||||
}
|
||||
|
||||
@ -409,10 +426,7 @@ int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
|
||||
int type = dquot->dq_id.type;
|
||||
struct super_block *sb = dquot->dq_sb;
|
||||
ssize_t ret;
|
||||
char *ddquot = getdqbuf(info->dqi_entry_size);
|
||||
|
||||
if (!ddquot)
|
||||
return -ENOMEM;
|
||||
GETDQBUF(info->dqi_entry_size);
|
||||
|
||||
/* dq_off is guarded by dqio_sem */
|
||||
if (!dquot->dq_off) {
|
||||
@ -420,14 +434,14 @@ int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
|
||||
if (ret < 0) {
|
||||
quota_error(sb, "Error %zd occurred while creating "
|
||||
"quota", ret);
|
||||
kfree(ddquot);
|
||||
FREEDQBUF();
|
||||
return ret;
|
||||
}
|
||||
}
|
||||
spin_lock(&dquot->dq_dqb_lock);
|
||||
info->dqi_ops->mem2disk_dqblk(ddquot, dquot);
|
||||
info->dqi_ops->mem2disk_dqblk(buf, dquot);
|
||||
spin_unlock(&dquot->dq_dqb_lock);
|
||||
ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size,
|
||||
ret = sb->s_op->quota_write(sb, type, buf, info->dqi_entry_size,
|
||||
dquot->dq_off);
|
||||
if (ret != info->dqi_entry_size) {
|
||||
quota_error(sb, "dquota write failed");
|
||||
@ -437,7 +451,7 @@ int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
|
||||
ret = 0;
|
||||
}
|
||||
dqstats_inc(DQST_WRITES);
|
||||
kfree(ddquot);
|
||||
FREEDQBUF();
|
||||
|
||||
return ret;
|
||||
}
|
||||
@ -448,11 +462,9 @@ static int free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot,
|
||||
uint blk)
|
||||
{
|
||||
struct qt_disk_dqdbheader *dh;
|
||||
char *buf = getdqbuf(info->dqi_usable_bs);
|
||||
int ret = 0;
|
||||
GETDQBUF(info->dqi_usable_bs);
|
||||
|
||||
if (!buf)
|
||||
return -ENOMEM;
|
||||
if (dquot->dq_off >> info->dqi_blocksize_bits != blk) {
|
||||
quota_error(dquot->dq_sb, "Quota structure has offset to "
|
||||
"other block (%u) than it should (%u)", blk,
|
||||
@ -504,7 +516,7 @@ static int free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot,
|
||||
}
|
||||
dquot->dq_off = 0; /* Quota is now unattached */
|
||||
out_buf:
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return ret;
|
||||
}
|
||||
|
||||
@ -512,13 +524,12 @@ out_buf:
|
||||
static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
|
||||
uint *blk, int depth)
|
||||
{
|
||||
char *buf = getdqbuf(info->dqi_usable_bs);
|
||||
int ret = 0;
|
||||
uint newblk;
|
||||
__le32 *ref = (__le32 *)buf;
|
||||
__le32 *ref;
|
||||
GETDQBUF(info->dqi_usable_bs);
|
||||
ref = (__le32 *)buf;
|
||||
|
||||
if (!buf)
|
||||
return -ENOMEM;
|
||||
ret = read_blk(info, *blk, buf);
|
||||
if (ret < 0) {
|
||||
quota_error(dquot->dq_sb, "Can't read quota data block %u",
|
||||
@ -559,7 +570,7 @@ static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
|
||||
}
|
||||
}
|
||||
out_buf:
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return ret;
|
||||
}
|
||||
|
||||
@ -578,13 +589,11 @@ EXPORT_SYMBOL(qtree_delete_dquot);
|
||||
static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info,
|
||||
struct dquot *dquot, uint blk)
|
||||
{
|
||||
char *buf = getdqbuf(info->dqi_usable_bs);
|
||||
loff_t ret = 0;
|
||||
int i;
|
||||
char *ddquot;
|
||||
GETDQBUF(info->dqi_usable_bs);
|
||||
|
||||
if (!buf)
|
||||
return -ENOMEM;
|
||||
ret = read_blk(info, blk, buf);
|
||||
if (ret < 0) {
|
||||
quota_error(dquot->dq_sb, "Can't read quota tree "
|
||||
@ -608,7 +617,7 @@ static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info,
|
||||
qt_disk_dqdbheader) + i * info->dqi_entry_size;
|
||||
}
|
||||
out_buf:
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return ret;
|
||||
}
|
||||
|
||||
@ -616,12 +625,11 @@ out_buf:
|
||||
static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
|
||||
struct dquot *dquot, uint blk, int depth)
|
||||
{
|
||||
char *buf = getdqbuf(info->dqi_usable_bs);
|
||||
loff_t ret = 0;
|
||||
__le32 *ref = (__le32 *)buf;
|
||||
__le32 *ref;
|
||||
GETDQBUF(info->dqi_usable_bs);
|
||||
ref = (__le32 *)buf;
|
||||
|
||||
if (!buf)
|
||||
return -ENOMEM;
|
||||
ret = read_blk(info, blk, buf);
|
||||
if (ret < 0) {
|
||||
quota_error(dquot->dq_sb, "Can't read quota tree block %u",
|
||||
@ -644,7 +652,7 @@ static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
|
||||
else
|
||||
ret = find_block_dqentry(info, dquot, blk);
|
||||
out_buf:
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return ret;
|
||||
}
|
||||
|
||||
@ -660,8 +668,9 @@ int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
|
||||
int type = dquot->dq_id.type;
|
||||
struct super_block *sb = dquot->dq_sb;
|
||||
loff_t offset;
|
||||
char *ddquot;
|
||||
int ret = 0;
|
||||
char *buf;
|
||||
char buf_onstack[STACK_ALLOC_SIZE] __aligned(8);
|
||||
|
||||
#ifdef __QUOTA_QT_PARANOIA
|
||||
/* Invalidated quota? */
|
||||
@ -687,10 +696,8 @@ int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
|
||||
}
|
||||
dquot->dq_off = offset;
|
||||
}
|
||||
ddquot = getdqbuf(info->dqi_entry_size);
|
||||
if (!ddquot)
|
||||
return -ENOMEM;
|
||||
ret = sb->s_op->quota_read(sb, type, ddquot, info->dqi_entry_size,
|
||||
__GETDQBUF(info->dqi_entry_size);
|
||||
ret = sb->s_op->quota_read(sb, type, buf, info->dqi_entry_size,
|
||||
dquot->dq_off);
|
||||
if (ret != info->dqi_entry_size) {
|
||||
if (ret >= 0)
|
||||
@ -699,18 +706,18 @@ int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
|
||||
from_kqid(&init_user_ns, dquot->dq_id));
|
||||
set_bit(DQ_FAKE_B, &dquot->dq_flags);
|
||||
memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
|
||||
kfree(ddquot);
|
||||
FREEDQBUF();
|
||||
goto out;
|
||||
}
|
||||
spin_lock(&dquot->dq_dqb_lock);
|
||||
info->dqi_ops->disk2mem_dqblk(dquot, ddquot);
|
||||
info->dqi_ops->disk2mem_dqblk(dquot, buf);
|
||||
if (!dquot->dq_dqb.dqb_bhardlimit &&
|
||||
!dquot->dq_dqb.dqb_bsoftlimit &&
|
||||
!dquot->dq_dqb.dqb_ihardlimit &&
|
||||
!dquot->dq_dqb.dqb_isoftlimit)
|
||||
set_bit(DQ_FAKE_B, &dquot->dq_flags);
|
||||
spin_unlock(&dquot->dq_dqb_lock);
|
||||
kfree(ddquot);
|
||||
FREEDQBUF();
|
||||
out:
|
||||
dqstats_inc(DQST_READS);
|
||||
return ret;
|
||||
@ -731,15 +738,13 @@ EXPORT_SYMBOL(qtree_release_dquot);
|
||||
static int find_next_id(struct qtree_mem_dqinfo *info, qid_t *id,
|
||||
unsigned int blk, int depth)
|
||||
{
|
||||
char *buf = getdqbuf(info->dqi_usable_bs);
|
||||
__le32 *ref = (__le32 *)buf;
|
||||
__le32 *ref;
|
||||
ssize_t ret;
|
||||
unsigned int epb = info->dqi_usable_bs >> 2;
|
||||
unsigned int level_inc = 1;
|
||||
int i;
|
||||
|
||||
if (!buf)
|
||||
return -ENOMEM;
|
||||
GETDQBUF(info->dqi_usable_bs);
|
||||
ref = (__le32 *)buf;
|
||||
|
||||
for (i = depth; i < info->dqi_qtree_depth - 1; i++)
|
||||
level_inc *= epb;
|
||||
@ -768,7 +773,7 @@ static int find_next_id(struct qtree_mem_dqinfo *info, qid_t *id,
|
||||
goto out_buf;
|
||||
}
|
||||
out_buf:
|
||||
kfree(buf);
|
||||
FREEDQBUF();
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user