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Groups > linux.kernel > #1299844

[PATCH 10/13] teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode

From Al Viro <viro@ZenIV.linux.org.uk>
Newsgroups linux.kernel
Subject [PATCH 10/13] teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode
Date 2016-01-01 07:50 +0100
Message-ID <qM1Hc-6Hb-5@gated-at.bofh.it> (permalink)
References <qM1xv-6DT-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 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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Thread

[RFC] ->get_link(), ->put_link() and cookies Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:40 +0100
  [PATCH 02/13] logfs: don't duplicate page_symlink_inode_operations Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:40 +0100
  [PATCH 11/13] teach nfs_get_link() to work in RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:40 +0100
  [PATCH 03/13] udf: don't duplicate page_symlink_inode_operations Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:40 +0100
    Re: [PATCH 03/13] udf: don't duplicate page_symlink_inode_operations Jan Kara <jack@suse.cz> - 2016-01-05 17:30 +0100
  [PATCH 01/13] switch befs long symlinks to page_symlink_operations Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:40 +0100
  [PATCH 09/13] teach shmem_get_link() to work in RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:40 +0100
  [PATCH 06/13] don't put symlink bodies in pagecache into highmem Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:40 +0100
  [PATCH 12/13] kill free_page_put_link() Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:50 +0100
  [PATCH 05/13] namei: page_getlink() and page_follow_link_light() are the same thing Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:50 +0100
  [PATCH 10/13] teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:50 +0100
  [PATCH 08/13] teach page_get_link() to work in RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:50 +0100
  [PATCH 04/13] ufs: get rid of ->setattr() for symlinks Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-01 07:50 +0100
  Re: [RFC] ->get_link(), ->put_link() and cookies Linus Torvalds <torvalds@linux-foundation.org> - 2016-01-03 21:00 +0100
    Re: [RFC] ->get_link(), ->put_link() and cookies Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-03 21:30 +0100
      Re: [RFC] ->get_link(), ->put_link() and cookies Linus Torvalds <torvalds@linux-foundation.org> - 2016-01-03 21:50 +0100
        Re: [RFC] ->get_link(), ->put_link() and cookies Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-03 22:50 +0100

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