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[PATCH v2 10/11] 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 v2 10/11] teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode
Date 2015-12-09 06:40 +0100
Message-ID <qDFDQ-485-13@gated-at.bofh.it> (permalink)
References <qDFDP-485-3@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

[PATCHSET v2] ->follow_link() without dropping from RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  [PATCH v2 02/11] logfs: don't duplicate page_symlink_inode_operations Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  [PATCH v2 08/11] teach page_get_link() to work in RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  [PATCH v2 10/11] teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  [PATCH v2 11/11] teach nfs_get_link() to work in RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  [PATCH v2 01/11] switch befs long symlinks to page_symlink_operations Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  [PATCH v2 03/11] udf: don't duplicate page_symlink_inode_operations Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  [PATCH v2 09/11] teach shmem_get_link() to work in RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  [PATCH v2 04/11] ufs: get rid of ->setattr() for symlinks Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 06:40 +0100
  Re: [PATCHSET v2] ->follow_link() without dropping from RCU mode Linus Torvalds <torvalds@linux-foundation.org> - 2015-12-09 18:30 +0100
    Re: [PATCHSET v2] ->follow_link() without dropping from RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-09 19:30 +0100
      Re: [PATCHSET v2] ->follow_link() without dropping from RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-10 01:20 +0100
        Re: [PATCHSET v2] ->follow_link() without dropping from RCU mode Al Viro <viro@ZenIV.linux.org.uk> - 2015-12-10 03:50 +0100
          Re: [PATCHSET v2] ->follow_link() without dropping from RCU mode Rasmus Villemoes <linux@rasmusvillemoes.dk> - 2015-12-11 08:50 +0100
  Re: [PATCHSET v2] ->follow_link() without dropping from RCU mode NeilBrown <neilb@suse.com> - 2015-12-09 23:00 +0100

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