[PATCH 1/5] proc: inline vma_stop into m_stop

[Alexey Dobriyan]

From: "Matthew Wilcox (Oracle)" <***@infradead.org>

Instead of calling vma_stop() from m_start() and m_next(), do its work
in m_stop().

Signed-off-by: Matthew Wilcox (Oracle) <***@infradead.org>
Signed-off-by: Alexey Dobriyan <***@gmail.com>
---
fs/proc/task_mmu.c | 34 +++++++++++++++-------------------
1 file changed, 15 insertions(+), 19 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 9442631fd4af..41f63df4789d 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -123,15 +123,6 @@ static void release_task_mempolicy(struct proc_maps_private *priv)
}
#endif

-static void vma_stop(struct proc_maps_private *priv)
-{
- struct mm_struct *mm = priv->mm;
-
- release_task_mempolicy(priv);
- up_read(&mm->mmap_sem);
- mmput(mm);
-}
-
static struct vm_area_struct *
m_next_vma(struct proc_maps_private *priv, struct vm_area_struct *vma)
{
@@ -163,11 +154,16 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
return ERR_PTR(-ESRCH);

mm = priv->mm;
- if (!mm || !mmget_not_zero(mm))
+ if (!mm || !mmget_not_zero(mm)) {
+ put_task_struct(priv->task);
+ priv->task = NULL;
return NULL;
+ }

if (down_read_killable(&mm->mmap_sem)) {
mmput(mm);
+ put_task_struct(priv->task);
+ priv->task = NULL;
return ERR_PTR(-EINTR);
}

@@ -195,7 +191,6 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
if (pos == mm->map_count && priv->tail_vma)
return priv->tail_vma;

- vma_stop(priv);
return NULL;
}

@@ -206,21 +201,22 @@ static void *m_next(struct seq_file *m, void *v, loff_t *pos)

(*pos)++;
next = m_next_vma(priv, v);
- if (!next)
- vma_stop(priv);
return next;
}

static void m_stop(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
+ struct mm_struct *mm = priv->mm;

- if (!IS_ERR_OR_NULL(v))
- vma_stop(priv);
- if (priv->task) {
- put_task_struct(priv->task);
- priv->task = NULL;
- }
+ if (!priv->task)
+ return;
+
+ release_task_mempolicy(priv);
+ up_read(&mm->mmap_sem);
+ mmput(mm);
+ put_task_struct(priv->task);
+ priv->task = NULL;
}

static int proc_maps_open(struct inode *inode, struct file *file,

[Alexey Dobriyan]

From: "Matthew Wilcox (Oracle)" <***@infradead.org>

Instead of setting m->version in the show method, set it in m_next(),
where it should be. Also remove the fallback code for failing to find
a vma, or version being zero.

Signed-off-by: Matthew Wilcox (Oracle) <***@infradead.org>
Signed-off-by: Alexey Dobriyan <***@gmail.com>
---
fs/proc/task_mmu.c | 38 ++++++--------------------------------
1 file changed, 6 insertions(+), 32 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 41f63df4789d..ff40d5d79f24 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -131,21 +131,14 @@ m_next_vma(struct proc_maps_private *priv, struct vm_area_struct *vma)
return vma->vm_next ?: priv->tail_vma;
}

-static void m_cache_vma(struct seq_file *m, struct vm_area_struct *vma)
-{
- if (m->count < m->size) /* vma is copied successfully */
- m->version = m_next_vma(m->private, vma) ? vma->vm_end : -1UL;
-}
-
static void *m_start(struct seq_file *m, loff_t *ppos)
{
struct proc_maps_private *priv = m->private;
unsigned long last_addr = m->version;
struct mm_struct *mm;
struct vm_area_struct *vma;
- unsigned int pos = *ppos;

- /* See m_cache_vma(). Zero at the start or after lseek. */
+ /* See m_next(). Zero at the start or after lseek. */
if (last_addr == -1UL)
return NULL;

@@ -170,28 +163,11 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
hold_task_mempolicy(priv);
priv->tail_vma = get_gate_vma(mm);

- if (last_addr) {
- vma = find_vma(mm, last_addr - 1);
- if (vma && vma->vm_start <= last_addr)
- vma = m_next_vma(priv, vma);
- if (vma)
- return vma;
- }
-
- m->version = 0;
- if (pos < mm->map_count) {
- for (vma = mm->mmap; pos; pos--) {
- m->version = vma->vm_start;
- vma = vma->vm_next;
- }
+ vma = find_vma(mm, last_addr);
+ if (vma)
return vma;
- }
-
- /* we do not bother to update m->version in this case */
- if (pos == mm->map_count && priv->tail_vma)
- return priv->tail_vma;

- return NULL;
+ return priv->tail_vma;
}

static void *m_next(struct seq_file *m, void *v, loff_t *pos)
@@ -201,6 +177,8 @@ static void *m_next(struct seq_file *m, void *v, loff_t *pos)

(*pos)++;
next = m_next_vma(priv, v);
+ m->version = next ? next->vm_start : -1UL;
+
return next;
}

@@ -359,7 +337,6 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
static int show_map(struct seq_file *m, void *v)
{
show_map_vma(m, v);
- m_cache_vma(m, v);
return 0;
}

@@ -843,8 +820,6 @@ static int show_smap(struct seq_file *m, void *v)
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
show_smap_vma_flags(m, vma);

- m_cache_vma(m, vma);
-
return 0;
}

@@ -1883,7 +1858,6 @@ static int show_numa_map(struct seq_file *m, void *v)
seq_printf(m, " kernelpagesize_kB=%lu", vma_kernel_pagesize(vma) >> 10);
out:
seq_putc(m, '\n');
- m_cache_vma(m, vma);
return 0;
}

[Alexey Dobriyan]

From: "Matthew Wilcox (Oracle)" <***@infradead.org>

The ppos is a private cursor, just like m->version. Use the canonical
cursor, not a special one.

Signed-off-by: Matthew Wilcox (Oracle) <***@infradead.org>
Signed-off-by: Alexey Dobriyan <***@gmail.com>
---
fs/proc/task_mmu.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ff40d5d79f24..9f10ef72b839 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -134,7 +134,7 @@ m_next_vma(struct proc_maps_private *priv, struct vm_area_struct *vma)
static void *m_start(struct seq_file *m, loff_t *ppos)
{
struct proc_maps_private *priv = m->private;
- unsigned long last_addr = m->version;
+ unsigned long last_addr = *ppos;
struct mm_struct *mm;
struct vm_area_struct *vma;

@@ -170,14 +170,13 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
return priv->tail_vma;
}

-static void *m_next(struct seq_file *m, void *v, loff_t *pos)
+static void *m_next(struct seq_file *m, void *v, loff_t *ppos)
{
struct proc_maps_private *priv = m->private;
struct vm_area_struct *next;

- (*pos)++;
next = m_next_vma(priv, v);
- m->version = next ? next->vm_start : -1UL;
+ *ppos = next ? next->vm_start : -1UL;

return next;
}

[Alexey Dobriyan]

From: "Matthew Wilcox (Oracle)" <***@infradead.org>

It's clearer to just put this inline.

Signed-off-by: Matthew Wilcox (Oracle) <***@infradead.org>
Signed-off-by: Alexey Dobriyan <***@gmail.com>
---
fs/proc/task_mmu.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 9f10ef72b839..87641df8c0d0 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -123,14 +123,6 @@ static void release_task_mempolicy(struct proc_maps_private *priv)
}
#endif

-static struct vm_area_struct *
-m_next_vma(struct proc_maps_private *priv, struct vm_area_struct *vma)
-{
- if (vma == priv->tail_vma)
- return NULL;
- return vma->vm_next ?: priv->tail_vma;
-}
-
static void *m_start(struct seq_file *m, loff_t *ppos)
{
struct proc_maps_private *priv = m->private;
@@ -173,9 +165,15 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
static void *m_next(struct seq_file *m, void *v, loff_t *ppos)
{
struct proc_maps_private *priv = m->private;
- struct vm_area_struct *next;
+ struct vm_area_struct *next, *vma = v;
+
+ if (vma == priv->tail_vma)
+ next = NULL;
+ else if (vma->vm_next)
+ next = vma->vm_next;
+ else
+ next = priv->tail_vma;

- next = m_next_vma(priv, v);
*ppos = next ? next->vm_start : -1UL;

return next;

[Alexey Dobriyan]

From: "Matthew Wilcox (Oracle)" <***@infradead.org>

The process maps file was the only user of version (introduced back
in 2005). Now that it uses ppos instead, we can remove it.

Signed-off-by: Matthew Wilcox (Oracle) <***@infradead.org>
Signed-off-by: Alexey Dobriyan <***@gmail.com>
---
fs/seq_file.c | 28 ----------------------------
include/linux/seq_file.h | 1 -
2 files changed, 29 deletions(-)

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 1600034a929b..79781ebd2145 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -67,13 +67,6 @@ int seq_open(struct file *file, const struct seq_operations *op)
// to the lifetime of the file.
p->file = file;

- /*
- * Wrappers around seq_open(e.g. swaps_open) need to be
- * aware of this. If they set f_version themselves, they
- * should call seq_open first and then set f_version.
- */
- file->f_version = 0;
-
/*
* seq_files support lseek() and pread(). They do not implement
* write() at all, but we clear FMODE_PWRITE here for historical
@@ -94,7 +87,6 @@ static int traverse(struct seq_file *m, loff_t offset)
int error = 0;
void *p;

- m->version = 0;
m->index = 0;
m->count = m->from = 0;
if (!offset)
@@ -160,26 +152,12 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)

mutex_lock(&m->lock);

- /*
- * seq_file->op->..m_start/m_stop/m_next may do special actions
- * or optimisations based on the file->f_version, so we want to
- * pass the file->f_version to those methods.
- *
- * seq_file->version is just copy of f_version, and seq_file
- * methods can treat it simply as file version.
- * It is copied in first and copied out after all operations.
- * It is convenient to have it as part of structure to avoid the
- * need of passing another argument to all the seq_file methods.
- */
- m->version = file->f_version;
-
/*
* if request is to read from zero offset, reset iterator to first
* record as it might have been already advanced by previous requests
*/
if (*ppos == 0) {
m->index = 0;
- m->version = 0;
m->count = 0;
}

@@ -190,7 +168,6 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
if (err) {
/* With prejudice... */
m->read_pos = 0;
- m->version = 0;
m->index = 0;
m->count = 0;
goto Done;
@@ -243,7 +220,6 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
m->buf = seq_buf_alloc(m->size <<= 1);
if (!m->buf)
goto Enomem;
- m->version = 0;
p = m->op->start(m, &m->index);
}
m->op->stop(m, p);
@@ -287,7 +263,6 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
*ppos += copied;
m->read_pos += copied;
}
- file->f_version = m->version;
mutex_unlock(&m->lock);
return copied;
Enomem:
@@ -313,7 +288,6 @@ loff_t seq_lseek(struct file *file, loff_t offset, int whence)
loff_t retval = -EINVAL;

mutex_lock(&m->lock);
- m->version = file->f_version;
switch (whence) {
case SEEK_CUR:
offset += file->f_pos;
@@ -329,7 +303,6 @@ loff_t seq_lseek(struct file *file, loff_t offset, int whence)
/* with extreme prejudice... */
file->f_pos = 0;
m->read_pos = 0;
- m->version = 0;
m->index = 0;
m->count = 0;
} else {
@@ -340,7 +313,6 @@ loff_t seq_lseek(struct file *file, loff_t offset, int whence)
file->f_pos = offset;
}
}
- file->f_version = m->version;
mutex_unlock(&m->lock);
return retval;
}
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 5998e1f4ff06..0d434bc4a779 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -21,7 +21,6 @@ struct seq_file {
size_t pad_until;
loff_t index;
loff_t read_pos;
- u64 version;
struct mutex lock;
const struct seq_operations *op;
int poll_event;