x86/fpu: Simplify __copy_xstate_to_kernel() return values

__copy_xstate_to_kernel() can only return 0 (because kernel copies cannot fail),
simplify the code throughout.

No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-11-mingo@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/fpu/xstate.c

@@ -924,7 +924,7 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
  * This is similar to user_regset_copyout(), but will not add offset to
  * the source data pointer or increment pos, count, kbuf, and ubuf.
  */
-static inline int
+static inline void
 __copy_xstate_to_kernel(void *kbuf, const void *data,
 			unsigned int offset, unsigned int size, unsigned int size_total)
 {
@@ -933,7 +933,6 @@ __copy_xstate_to_kernel(void *kbuf, const void *data,
 
 		memcpy(kbuf + offset, data, copy);
 	}
-	return 0;
 }
 
 /*
@@ -946,8 +945,8 @@ __copy_xstate_to_kernel(void *kbuf, const void *data,
 int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total)
 {
 	unsigned int offset, size;
-	int ret, i;
 	struct xstate_header header;
+	int i;
 
 	/*
 	 * Currently copy_regset_to_user() starts from pos 0:
@@ -968,9 +967,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int of
 	offset = offsetof(struct xregs_state, header);
 	size = sizeof(header);
 
-	ret = __copy_xstate_to_kernel(kbuf, &header, offset, size, size_total);
-	if (ret)
-		return ret;
+	__copy_xstate_to_kernel(kbuf, &header, offset, size, size_total);
 
 	for (i = 0; i < XFEATURE_MAX; i++) {
 		/*
@@ -986,9 +983,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int of
 			if (offset + size > size_total)
 				break;
 
-			ret = __copy_xstate_to_kernel(kbuf, src, offset, size, size_total);
-			if (ret)
-				return ret;
+			__copy_xstate_to_kernel(kbuf, src, offset, size, size_total);
 		}
 
 	}
@@ -999,9 +994,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int of
 	offset = offsetof(struct fxregs_state, sw_reserved);
 	size = sizeof(xstate_fx_sw_bytes);
 
-	ret = __copy_xstate_to_kernel(kbuf, xstate_fx_sw_bytes, offset, size, size_total);
-	if (ret)
-		return ret;
+	__copy_xstate_to_kernel(kbuf, xstate_fx_sw_bytes, offset, size, size_total);
 
 	return 0;
 }