um: Abandon the _PAGE_NEWPROT bit

When a PTE is updated in the page table, the _PAGE_NEWPAGE bit will
always be set. And the corresponding page will always be mapped or
unmapped depending on whether the PTE is present or not. The check
on the _PAGE_NEWPROT bit is not really reachable. Abandoning it will
allow us to simplify the code and remove the unreachable code.

Reviewed-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011102354.1682626-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 0 insertions, 21 deletions

diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index 9a13ac23c606..d7f1814b0e5a 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -217,24 +217,3 @@ int unmap(struct mm_id *mm_idp, unsigned long addr, unsigned long len)
 
 	return 0;
 }
-
-int protect(struct mm_id *mm_idp, unsigned long addr, unsigned long len,
-	    unsigned int prot)
-{
-	struct stub_syscall *sc;
-
-	/* Compress with previous syscall if that is possible */
-	sc = syscall_stub_get_previous(mm_idp, STUB_SYSCALL_MPROTECT, addr);
-	if (sc && sc->mem.prot == prot) {
-		sc->mem.length += len;
-		return 0;
-	}
-
-	sc = syscall_stub_alloc(mm_idp);
-	sc->syscall = STUB_SYSCALL_MPROTECT;
-	sc->mem.addr = addr;
-	sc->mem.length = len;
-	sc->mem.prot = prot;
-
-	return 0;
-}