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Subject[PATCH 138/208] x86/fpu: Simplify fpu__unlazy_stopped() error handling
Date
Now that FPU contexts are always allocated, fpu__unlazy_stopped()
cannot fail. Remove its error return and propagate the changes to
the callers.

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/fpu/core.c | 48 +++++++++++++-----------------------------------
1 file changed, 13 insertions(+), 35 deletions(-)

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index ca1b74831887..b8b03547072d 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -296,24 +296,18 @@ EXPORT_SYMBOL_GPL(fpstate_init_curr);
* the read-only case, it's not strictly necessary for
* read-only access to the context.
*/
-static int fpu__unlazy_stopped(struct fpu *child_fpu)
+static void fpu__unlazy_stopped(struct fpu *child_fpu)
{
- int ret;
-
- if (WARN_ON_ONCE(child_fpu == &current->thread.fpu))
- return -EINVAL;
+ WARN_ON_ONCE(child_fpu == &current->thread.fpu);

if (child_fpu->fpstate_active) {
child_fpu->last_cpu = -1;
- return 0;
- }
-
- fpstate_init(child_fpu);
-
- /* Safe to do for stopped child tasks: */
- child_fpu->fpstate_active = 1;
+ } else {
+ fpstate_init(child_fpu);

- return 0;
+ /* Safe to do for stopped child tasks: */
+ child_fpu->fpstate_active = 1;
+ }
}

/*
@@ -389,15 +383,11 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
void *kbuf, void __user *ubuf)
{
struct fpu *fpu = &target->thread.fpu;
- int ret;

if (!cpu_has_fxsr)
return -ENODEV;

- ret = fpu__unlazy_stopped(fpu);
- if (ret)
- return ret;
-
+ fpu__unlazy_stopped(fpu);
sanitize_i387_state(target);

return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
@@ -414,10 +404,7 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
if (!cpu_has_fxsr)
return -ENODEV;

- ret = fpu__unlazy_stopped(fpu);
- if (ret)
- return ret;
-
+ fpu__unlazy_stopped(fpu);
sanitize_i387_state(target);

ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
@@ -449,9 +436,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
if (!cpu_has_xsave)
return -ENODEV;

- ret = fpu__unlazy_stopped(fpu);
- if (ret)
- return ret;
+ fpu__unlazy_stopped(fpu);

xsave = &fpu->state.xsave;

@@ -480,9 +465,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
if (!cpu_has_xsave)
return -ENODEV;

- ret = fpu__unlazy_stopped(fpu);
- if (ret)
- return ret;
+ fpu__unlazy_stopped(fpu);

xsave = &fpu->state.xsave;

@@ -643,11 +626,8 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
{
struct fpu *fpu = &target->thread.fpu;
struct user_i387_ia32_struct env;
- int ret;

- ret = fpu__unlazy_stopped(fpu);
- if (ret)
- return ret;
+ fpu__unlazy_stopped(fpu);

if (!static_cpu_has(X86_FEATURE_FPU))
return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
@@ -677,9 +657,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
struct user_i387_ia32_struct env;
int ret;

- ret = fpu__unlazy_stopped(fpu);
- if (ret)
- return ret;
+ fpu__unlazy_stopped(fpu);

sanitize_i387_state(target);

--
2.1.0


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