[PATCH 10/10] teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode

From: Al Viro
Date: Tue Nov 17 2015 - 18:04:36 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/proc/self.c | 8 +++-----
fs/proc/thread_self.c | 9 ++++-----
2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/fs/proc/self.c b/fs/proc/self.c
index 9dd0ae6..7a8b19e 100644
--- a/fs/proc/self.c
+++ b/fs/proc/self.c
@@ -25,14 +25,12 @@ static const char *proc_self_get_link(struct dentry *dentry,
pid_t tgid = task_tgid_nr_ns(current, ns);
char *name;

- if (!dentry)
- return ERR_PTR(-ECHILD);
if (!tgid)
return ERR_PTR(-ENOENT);
/* 11 for max length of signed int in decimal + NULL term */
- name = kmalloc(12, GFP_KERNEL);
- if (!name)
- return ERR_PTR(-ENOMEM);
+ name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC);
+ if (unlikely(!name))
+ return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
sprintf(name, "%d", tgid);
return *cookie = name;
}
diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c
index 50eef6f..03eaa84 100644
--- a/fs/proc/thread_self.c
+++ b/fs/proc/thread_self.c
@@ -27,13 +27,12 @@ static const char *proc_thread_self_get_link(struct dentry *dentry,
pid_t pid = task_pid_nr_ns(current, ns);
char *name;

- if (!dentry)
- return ERR_PTR(-ECHILD);
if (!pid)
return ERR_PTR(-ENOENT);
- name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, GFP_KERNEL);
- if (!name)
- return ERR_PTR(-ENOMEM);
+ name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF,
+ dentry ? GFP_KERNEL : GFP_ATOMIC);
+ if (unlikely(!name))
+ return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
sprintf(name, "%d/task/%d", tgid, pid);
return *cookie = name;
}
--
2.1.4

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