The patch titled
proc: Remove tasklist_lock from proc_task_readdir.
has been removed from the -mm tree. Its filename is
proc-remove-tasklist_lock-from-proc_task_readdir.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: proc: Remove tasklist_lock from proc_task_readdir.
From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
This is just like my previous removal of tasklist_lock from first_tgid, and
next_tgid. It simply had to wait until it was rcu safe to walk the thread
list.
This should be the last instance of the tasklist_lock in proc. So user
processes should not be able to influence the tasklist lock hold times.
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/proc/base.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff -puN fs/proc/base.c~proc-remove-tasklist_lock-from-proc_task_readdir fs/proc/base.c
--- a/fs/proc/base.c~proc-remove-tasklist_lock-from-proc_task_readdir
+++ a/fs/proc/base.c
@@ -2224,11 +2224,12 @@ int proc_pid_readdir(struct file * filp,
* In the case of a seek we start with the leader and walk nr
* threads past it.
*/
-static struct task_struct *first_tid(struct task_struct *leader, int tid, int nr)
+static struct task_struct *first_tid(struct task_struct *leader,
+ int tid, int nr)
{
struct task_struct *pos = NULL;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
/* Attempt to start with the pid of a thread */
if (tid && (nr > 0)) {
pos = find_task_by_pid(tid);
@@ -2258,7 +2259,7 @@ static struct task_struct *first_tid(str
}
pos = NULL;
done:
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
return pos;
}
@@ -2271,7 +2272,7 @@ done:
static struct task_struct *next_tid(struct task_struct *start)
{
struct task_struct *pos;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
pos = start;
if (pid_alive(start))
pos = next_thread(start);
@@ -2279,7 +2280,7 @@ static struct task_struct *next_tid(stru
get_task_struct(pos);
else
pos = NULL;
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
put_task_struct(start);
return pos;
}
_
Patches currently in -mm which might be from ebiederm@xxxxxxxxxxxx are
origin.patch
powerpc-adding-the-use-of-the-firmware-soft-reset-nmi-to-kdump.patch
proc-sysctl-add-_proc_do_string-helper.patch
namespaces-add-nsproxy.patch
namespaces-add-nsproxy-dont-include-compileh.patch
namespaces-incorporate-fs-namespace-into-nsproxy.patch
namespaces-utsname-introduce-temporary-helpers.patch
namespaces-utsname-switch-to-using-uts-namespaces.patch
namespaces-utsname-switch-to-using-uts-namespaces-alpha-fix.patch
namespaces-utsname-switch-to-using-uts-namespaces-cleanup.patch
namespaces-utsname-use-init_utsname-when-appropriate.patch
namespaces-utsname-use-init_utsname-when-appropriate-cifs-update.patch
namespaces-utsname-implement-utsname-namespaces.patch
namespaces-utsname-implement-utsname-namespaces-export.patch
namespaces-utsname-implement-utsname-namespaces-dont-include-compileh.patch
namespaces-utsname-sysctl-hack.patch
namespaces-utsname-sysctl-hack-cleanup.patch
namespaces-utsname-sysctl-hack-cleanup-2.patch
namespaces-utsname-sysctl-hack-cleanup-2-fix.patch
namespaces-utsname-remove-system_utsname.patch
namespaces-utsname-implement-clone_newuts-flag.patch
uts-copy-nsproxy-only-when-needed.patch
ipc-namespace-core-fix.patch
ipc-namespace-core-unshare-fix.patch
ipc-namespace-utils-compilation-fix.patch
genirq-irq-document-what-an-irq-is.patch
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