x86/fpu: Remove the 'start_pos' parameter from the __copy_xstate_to_*() functions

'start_pos' is always 0, so remove it and remove the pointless check of 'pos < 0'
which can not ever be true as 'pos' is unsigned ...

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/20170923130016.21448-8-mingo@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/fpu/xstate.c

@@ -927,9 +927,9 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 static inline int
 __copy_xstate_to_kernel(void *kbuf,
 			const void *data,
-			unsigned int pos, unsigned int count, int start_pos, int end_pos)
+			unsigned int pos, unsigned int count, int end_pos)
 {
-	if ((count == 0) || (pos < start_pos))
+	if (!count)
 		return 0;
 
 	if (end_pos < 0 || pos < end_pos) {
@@ -972,7 +972,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po
 	offset = offsetof(struct xregs_state, header);
 	size = sizeof(header);
 
-	ret = __copy_xstate_to_kernel(kbuf, &header, offset, size, 0, count);
+	ret = __copy_xstate_to_kernel(kbuf, &header, offset, size, count);
 	if (ret)
 		return ret;
 
@@ -986,7 +986,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po
 			offset = xstate_offsets[i];
 			size = xstate_sizes[i];
 
-			ret = __copy_xstate_to_kernel(kbuf, src, offset, size, 0, count);
+			ret = __copy_xstate_to_kernel(kbuf, src, offset, size, count);
 			if (ret)
 				return ret;
 
@@ -1002,7 +1002,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po
 	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, 0, count);
+	ret = __copy_xstate_to_kernel(kbuf, xstate_fx_sw_bytes, offset, size, count);
 	if (ret)
 		return ret;
 
@@ -1010,9 +1010,9 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po
 }
 
 static inline int
-__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int pos, unsigned int count, int start_pos, int end_pos)
+__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int pos, unsigned int count, int end_pos)
 {
-	if ((count == 0) || (pos < start_pos))
+	if (!count)
 		return 0;
 
 	if (end_pos < 0 || pos < end_pos) {
@@ -1055,7 +1055,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i
 	offset = offsetof(struct xregs_state, header);
 	size = sizeof(header);
 
-	ret = __copy_xstate_to_user(ubuf, &header, offset, size, 0, count);
+	ret = __copy_xstate_to_user(ubuf, &header, offset, size, count);
 	if (ret)
 		return ret;
 
@@ -1069,7 +1069,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i
 			offset = xstate_offsets[i];
 			size = xstate_sizes[i];
 
-			ret = __copy_xstate_to_user(ubuf, src, offset, size, 0, count);
+			ret = __copy_xstate_to_user(ubuf, src, offset, size, count);
 			if (ret)
 				return ret;
 
@@ -1085,7 +1085,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i
 	offset = offsetof(struct fxregs_state, sw_reserved);
 	size = sizeof(xstate_fx_sw_bytes);
 
-	ret = __copy_xstate_to_user(ubuf, xstate_fx_sw_bytes, offset, size, 0, count);
+	ret = __copy_xstate_to_user(ubuf, xstate_fx_sw_bytes, offset, size, count);
 	if (ret)
 		return ret;