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@google.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);