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Message-ID: <20250731220024.702621-3-surenb@google.com>
Date: Thu, 31 Jul 2025 15:00:23 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: akpm@...ux-foundation.org
Cc: Liam.Howlett@...cle.com, lorenzo.stoakes@...cle.com, david@...hat.com,
vbabka@...e.cz, peterx@...hat.com, jannh@...gle.com, hannes@...xchg.org,
mhocko@...nel.org, paulmck@...nel.org, shuah@...nel.org, adobriyan@...il.com,
brauner@...nel.org, josef@...icpanda.com, yebin10@...wei.com,
linux@...ssschuh.net, willy@...radead.org, osalvador@...e.de,
andrii@...nel.org, ryan.roberts@....com, christophe.leroy@...roup.eu,
tjmercier@...gle.com, kaleshsingh@...gle.com, aha310510@...il.com,
linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org, linux-kselftest@...r.kernel.org, surenb@...gle.com
Subject: [PATCH 2/3] fs/proc/task_mmu: factor out proc_maps_private fields
used by PROCMAP_QUERY
Refactor struct proc_maps_private so that the fields used by PROCMAP_QUERY
ioctl are moved into a separate structure. In the next patch this allows
ioctl to reuse some of the functions used for reading /proc/pid/maps
without using file->private_data. This prevents concurrent modification
of file->private_data members by ioctl and /proc/pid/maps readers.
The change is pure code refactoring and has no functional changes.
Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
---
fs/proc/internal.h | 15 ++++++----
fs/proc/task_mmu.c | 70 +++++++++++++++++++++++-----------------------
2 files changed, 45 insertions(+), 40 deletions(-)
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 7c235451c5ea..e2447b22592e 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -379,16 +379,21 @@ extern void proc_self_init(void);
* task_[no]mmu.c
*/
struct mem_size_stats;
-struct proc_maps_private {
- struct inode *inode;
- struct task_struct *task;
+
+struct proc_maps_query_data {
struct mm_struct *mm;
- struct vma_iterator iter;
- loff_t last_pos;
#ifdef CONFIG_PER_VMA_LOCK
bool mmap_locked;
struct vm_area_struct *locked_vma;
#endif
+};
+
+struct proc_maps_private {
+ struct inode *inode;
+ struct task_struct *task;
+ struct vma_iterator iter;
+ loff_t last_pos;
+ struct proc_maps_query_data query;
#ifdef CONFIG_NUMA
struct mempolicy *task_mempolicy;
#endif
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3d6d8a9f13fc..509fa162760a 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -132,11 +132,11 @@ static void release_task_mempolicy(struct proc_maps_private *priv)
#ifdef CONFIG_PER_VMA_LOCK
-static void unlock_vma(struct proc_maps_private *priv)
+static void unlock_vma(struct proc_maps_query_data *query)
{
- if (priv->locked_vma) {
- vma_end_read(priv->locked_vma);
- priv->locked_vma = NULL;
+ if (query->locked_vma) {
+ vma_end_read(query->locked_vma);
+ query->locked_vma = NULL;
}
}
@@ -151,14 +151,14 @@ static inline bool lock_vma_range(struct seq_file *m,
* walking the vma tree under rcu read protection.
*/
if (m->op != &proc_pid_maps_op) {
- if (mmap_read_lock_killable(priv->mm))
+ if (mmap_read_lock_killable(priv->query.mm))
return false;
- priv->mmap_locked = true;
+ priv->query.mmap_locked = true;
} else {
rcu_read_lock();
- priv->locked_vma = NULL;
- priv->mmap_locked = false;
+ priv->query.locked_vma = NULL;
+ priv->query.mmap_locked = false;
}
return true;
@@ -166,10 +166,10 @@ static inline bool lock_vma_range(struct seq_file *m,
static inline void unlock_vma_range(struct proc_maps_private *priv)
{
- if (priv->mmap_locked) {
- mmap_read_unlock(priv->mm);
+ if (priv->query.mmap_locked) {
+ mmap_read_unlock(priv->query.mm);
} else {
- unlock_vma(priv);
+ unlock_vma(&priv->query);
rcu_read_unlock();
}
}
@@ -179,13 +179,13 @@ static struct vm_area_struct *get_next_vma(struct proc_maps_private *priv,
{
struct vm_area_struct *vma;
- if (priv->mmap_locked)
+ if (priv->query.mmap_locked)
return vma_next(&priv->iter);
- unlock_vma(priv);
- vma = lock_next_vma(priv->mm, &priv->iter, last_pos);
+ unlock_vma(&priv->query);
+ vma = lock_next_vma(priv->query.mm, &priv->iter, last_pos);
if (!IS_ERR_OR_NULL(vma))
- priv->locked_vma = vma;
+ priv->query.locked_vma = vma;
return vma;
}
@@ -193,14 +193,14 @@ static struct vm_area_struct *get_next_vma(struct proc_maps_private *priv,
static inline bool fallback_to_mmap_lock(struct proc_maps_private *priv,
loff_t pos)
{
- if (priv->mmap_locked)
+ if (priv->query.mmap_locked)
return false;
rcu_read_unlock();
- mmap_read_lock(priv->mm);
+ mmap_read_lock(priv->query.mm);
/* Reinitialize the iterator after taking mmap_lock */
vma_iter_set(&priv->iter, pos);
- priv->mmap_locked = true;
+ priv->query.mmap_locked = true;
return true;
}
@@ -210,12 +210,12 @@ static inline bool fallback_to_mmap_lock(struct proc_maps_private *priv,
static inline bool lock_vma_range(struct seq_file *m,
struct proc_maps_private *priv)
{
- return mmap_read_lock_killable(priv->mm) == 0;
+ return mmap_read_lock_killable(priv->query.mm) == 0;
}
static inline void unlock_vma_range(struct proc_maps_private *priv)
{
- mmap_read_unlock(priv->mm);
+ mmap_read_unlock(priv->query.mm);
}
static struct vm_area_struct *get_next_vma(struct proc_maps_private *priv,
@@ -258,7 +258,7 @@ static struct vm_area_struct *proc_get_vma(struct seq_file *m, loff_t *ppos)
*ppos = vma->vm_end;
} else {
*ppos = SENTINEL_VMA_GATE;
- vma = get_gate_vma(priv->mm);
+ vma = get_gate_vma(priv->query.mm);
}
return vma;
@@ -278,7 +278,7 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
if (!priv->task)
return ERR_PTR(-ESRCH);
- mm = priv->mm;
+ mm = priv->query.mm;
if (!mm || !mmget_not_zero(mm)) {
put_task_struct(priv->task);
priv->task = NULL;
@@ -318,7 +318,7 @@ static void *m_next(struct seq_file *m, void *v, loff_t *ppos)
static void m_stop(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
- struct mm_struct *mm = priv->mm;
+ struct mm_struct *mm = priv->query.mm;
if (!priv->task)
return;
@@ -339,9 +339,9 @@ static int proc_maps_open(struct inode *inode, struct file *file,
return -ENOMEM;
priv->inode = inode;
- priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
- if (IS_ERR_OR_NULL(priv->mm)) {
- int err = priv->mm ? PTR_ERR(priv->mm) : -ESRCH;
+ priv->query.mm = proc_mem_open(inode, PTRACE_MODE_READ);
+ if (IS_ERR_OR_NULL(priv->query.mm)) {
+ int err = priv->query.mm ? PTR_ERR(priv->query.mm) : -ESRCH;
seq_release_private(inode, file);
return err;
@@ -355,8 +355,8 @@ static int proc_map_release(struct inode *inode, struct file *file)
struct seq_file *seq = file->private_data;
struct proc_maps_private *priv = seq->private;
- if (priv->mm)
- mmdrop(priv->mm);
+ if (priv->query.mm)
+ mmdrop(priv->query.mm);
return seq_release_private(inode, file);
}
@@ -610,7 +610,7 @@ static int do_procmap_query(struct proc_maps_private *priv, void __user *uarg)
if (!!karg.build_id_size != !!karg.build_id_addr)
return -EINVAL;
- mm = priv->mm;
+ mm = priv->query.mm;
if (!mm || !mmget_not_zero(mm))
return -ESRCH;
@@ -1307,7 +1307,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
struct mem_size_stats mss = {};
- struct mm_struct *mm = priv->mm;
+ struct mm_struct *mm = priv->query.mm;
struct vm_area_struct *vma;
unsigned long vma_start = 0, last_vma_end = 0;
int ret = 0;
@@ -1452,9 +1452,9 @@ static int smaps_rollup_open(struct inode *inode, struct file *file)
goto out_free;
priv->inode = inode;
- priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
- if (IS_ERR_OR_NULL(priv->mm)) {
- ret = priv->mm ? PTR_ERR(priv->mm) : -ESRCH;
+ priv->query.mm = proc_mem_open(inode, PTRACE_MODE_READ);
+ if (IS_ERR_OR_NULL(priv->query.mm)) {
+ ret = priv->query.mm ? PTR_ERR(priv->query.mm) : -ESRCH;
single_release(inode, file);
goto out_free;
@@ -1472,8 +1472,8 @@ static int smaps_rollup_release(struct inode *inode, struct file *file)
struct seq_file *seq = file->private_data;
struct proc_maps_private *priv = seq->private;
- if (priv->mm)
- mmdrop(priv->mm);
+ if (priv->query.mm)
+ mmdrop(priv->query.mm);
kfree(priv);
return single_release(inode, file);
--
2.50.1.565.gc32cd1483b-goog
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