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Message-Id: <20060831213530.29363.6372.stgit@warthog.cambridge.redhat.com>
Date: Thu, 31 Aug 2006 22:35:30 +0100
From: David Howells <dhowells@...hat.com>
To: torvalds@...l.org, akpm@...l.org
Cc: linux-kernel@...r.kernel.org, uclinux-dev@...inux.org,
dhowells@...hat.com
Subject: [PATCH 1/4] NOMMU: Implement /proc/pid/maps for NOMMU
From: David Howells <dhowells@...hat.com>
Implement /proc/pid/maps for NOMMU by reading the vm_area_list attached to
current->mm->context.vmlist.
Signed-Off-By: David Howells <dhowells@...hat.com>
---
Documentation/nommu-mmap.txt | 3 ++
fs/proc/internal.h | 1 +
fs/proc/nommu.c | 20 ++++++++---
fs/proc/task_nommu.c | 74 ++++++++++++++++++++++++++++++++++--------
include/linux/proc_fs.h | 2 +
5 files changed, 80 insertions(+), 20 deletions(-)
diff --git a/Documentation/nommu-mmap.txt b/Documentation/nommu-mmap.txt
index b88ebe4..83f4b08 100644
--- a/Documentation/nommu-mmap.txt
+++ b/Documentation/nommu-mmap.txt
@@ -116,6 +116,9 @@ FURTHER NOTES ON NO-MMU MMAP
(*) A list of all the mappings on the system is visible through /proc/maps in
no-MMU mode.
+ (*) A list of all the mappings in use by a process is visible through
+ /proc/<pid>/maps in no-MMU mode.
+
(*) Supplying MAP_FIXED or a requesting a particular mapping address will
result in an error.
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 146a434..987c773 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -28,6 +28,7 @@ do { \
(vmi)->largest_chunk = 0; \
} while(0)
+extern int nommu_vma_show(struct seq_file *, struct vm_area_struct *);
#endif
extern void create_seq_entry(char *name, mode_t mode, const struct file_operations *f);
diff --git a/fs/proc/nommu.c b/fs/proc/nommu.c
index cff10ab..d7dbdf9 100644
--- a/fs/proc/nommu.c
+++ b/fs/proc/nommu.c
@@ -33,19 +33,15 @@ #include <asm/div64.h>
#include "internal.h"
/*
- * display a list of all the VMAs the kernel knows about
- * - nommu kernals have a single flat list
+ * display a single VMA to a sequenced file
*/
-static int nommu_vma_list_show(struct seq_file *m, void *v)
+int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
{
- struct vm_area_struct *vma;
unsigned long ino = 0;
struct file *file;
dev_t dev = 0;
int flags, len;
- vma = rb_entry((struct rb_node *) v, struct vm_area_struct, vm_rb);
-
flags = vma->vm_flags;
file = vma->vm_file;
@@ -78,6 +74,18 @@ static int nommu_vma_list_show(struct se
return 0;
}
+/*
+ * display a list of all the VMAs the kernel knows about
+ * - nommu kernals have a single flat list
+ */
+static int nommu_vma_list_show(struct seq_file *m, void *v)
+{
+ struct vm_area_struct *vma;
+
+ vma = rb_entry((struct rb_node *) v, struct vm_area_struct, vm_rb);
+ return nommu_vma_show(m, vma);
+}
+
static void *nommu_vma_list_start(struct seq_file *m, loff_t *_pos)
{
struct rb_node *_rb;
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 4616ed5..091aa8e 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -138,25 +138,63 @@ out:
}
/*
- * Albert D. Cahalan suggested to fake entries for the traditional
- * sections here. This might be worth investigating.
+ * display mapping lines for a particular process's /proc/pid/maps
*/
-static int show_map(struct seq_file *m, void *v)
+static int show_map(struct seq_file *m, void *_vml)
{
- return 0;
+ struct vm_list_struct *vml = _vml;
+ return nommu_vma_show(m, vml->vma);
}
+
static void *m_start(struct seq_file *m, loff_t *pos)
{
+ struct proc_maps_private *priv = m->private;
+ struct vm_list_struct *vml;
+ struct mm_struct *mm;
+ loff_t n = *pos;
+
+ /* pin the task and mm whilst we play with them */
+ priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
+ if (!priv->task)
+ return NULL;
+
+ mm = get_task_mm(priv->task);
+ if (!mm) {
+ put_task_struct(priv->task);
+ priv->task = NULL;
+ return NULL;
+ }
+
+ down_read(&mm->mmap_sem);
+
+ /* start from the Nth VMA */
+ for (vml = mm->context.vmlist; vml; vml = vml->next)
+ if (n-- == 0)
+ return vml;
return NULL;
}
-static void m_stop(struct seq_file *m, void *v)
+
+static void m_stop(struct seq_file *m, void *_vml)
{
+ struct proc_maps_private *priv = m->private;
+
+ if (priv->task) {
+ struct mm_struct *mm = priv->task->mm;
+ up_read(&mm->mmap_sem);
+ mmput(mm);
+ put_task_struct(priv->task);
+ }
}
-static void *m_next(struct seq_file *m, void *v, loff_t *pos)
+
+static void *m_next(struct seq_file *m, void *_vml, loff_t *pos)
{
- return NULL;
+ struct vm_list_struct *vml = _vml;
+
+ (*pos)++;
+ return vml ? vml->next : NULL;
}
-static struct seq_operations proc_pid_maps_op = {
+
+static struct seq_operations proc_pid_maps_ops = {
.start = m_start,
.next = m_next,
.stop = m_stop,
@@ -165,11 +203,19 @@ static struct seq_operations proc_pid_ma
static int maps_open(struct inode *inode, struct file *file)
{
- int ret;
- ret = seq_open(file, &proc_pid_maps_op);
- if (!ret) {
- struct seq_file *m = file->private_data;
- m->private = NULL;
+ struct proc_maps_private *priv;
+ int ret = -ENOMEM;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (priv) {
+ priv->pid = proc_pid(inode);
+ ret = seq_open(file, &proc_pid_maps_ops);
+ if (!ret) {
+ struct seq_file *m = file->private_data;
+ m->private = priv;
+ } else {
+ kfree(priv);
+ }
}
return ret;
}
@@ -178,6 +224,6 @@ struct file_operations proc_maps_operati
.open = maps_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = seq_release,
+ .release = seq_release_private,
};
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 17e7578..73beb46 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -269,7 +269,9 @@ static inline struct proc_dir_entry *PDE
struct proc_maps_private {
struct pid *pid;
struct task_struct *task;
+#ifdef CONFIG_MMU
struct vm_area_struct *tail_vma;
+#endif
};
#endif /* _LINUX_PROC_FS_H */
-
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