68 lines
1.7 KiB
Diff
68 lines
1.7 KiB
Diff
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From: David Herrmann <dh.herrmann@gmail.com>
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Date: Mon, 20 Apr 2015 11:13:54 +0200
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Subject: [PATCH] kdbus: no need to ref current->mm
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If we access current->mm temporarily, there is no need to ref it. It can
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only be changed by us, so no-one can race with us.
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Avoid ref'ing and unref'ing it just to access some of its fields, similar
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to what syscalls in mm/ do.
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Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
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---
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ipc/kdbus/metadata.c | 21 +++------------------
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1 file changed, 3 insertions(+), 18 deletions(-)
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diff --git a/ipc/kdbus/metadata.c b/ipc/kdbus/metadata.c
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index a85eac34a5c4..c36b9cc67637 100644
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--- a/ipc/kdbus/metadata.c
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+++ b/ipc/kdbus/metadata.c
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@@ -282,15 +282,10 @@ static void kdbus_meta_proc_collect_pid_comm(struct kdbus_meta_proc *mp)
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static void kdbus_meta_proc_collect_exe(struct kdbus_meta_proc *mp)
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{
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- struct mm_struct *mm;
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struct file *exe_file;
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- mm = get_task_mm(current);
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- if (!mm)
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- return;
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-
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rcu_read_lock();
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- exe_file = rcu_dereference(mm->exe_file);
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+ exe_file = rcu_dereference(current->mm->exe_file);
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if (exe_file) {
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mp->exe_path = exe_file->f_path;
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path_get(&mp->exe_path);
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@@ -298,28 +293,18 @@ static void kdbus_meta_proc_collect_exe(struct kdbus_meta_proc *mp)
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mp->valid |= KDBUS_ATTACH_EXE;
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}
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rcu_read_unlock();
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-
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- mmput(mm);
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}
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static int kdbus_meta_proc_collect_cmdline(struct kdbus_meta_proc *mp)
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{
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- struct mm_struct *mm;
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+ struct mm_struct *mm = current->mm;
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char *cmdline;
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- mm = get_task_mm(current);
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- if (!mm)
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- return 0;
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-
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- if (!mm->arg_end) {
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- mmput(mm);
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+ if (!mm->arg_end)
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return 0;
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- }
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cmdline = strndup_user((const char __user *)mm->arg_start,
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mm->arg_end - mm->arg_start);
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- mmput(mm);
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-
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if (IS_ERR(cmdline))
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return PTR_ERR(cmdline);
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