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Date:      Fri, 30 Oct 2015 13:05:39 +0000 (UTC)
From:      Gleb Smirnoff <glebius@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org
Subject:   svn commit: r290194 - stable/9/sys/vm
Message-ID:  <201510301305.t9UD5d2T024364@repo.freebsd.org>
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Author: glebius
Date: Fri Oct 30 13:05:39 2015
New Revision: 290194
URL: https://svnweb.freebsd.org/changeset/base/290194

Log:
  MFC r287591 by kib:
  There is no reason in the current kernel to disallow write access to
  the COW wired entry if the entry permissions allow it.  Remove the check.

Modified:
  stable/9/sys/vm/vm_map.c
Directory Properties:
  stable/9/sys/   (props changed)

Modified: stable/9/sys/vm/vm_map.c
==============================================================================
--- stable/9/sys/vm/vm_map.c	Fri Oct 30 12:37:40 2015	(r290193)
+++ stable/9/sys/vm/vm_map.c	Fri Oct 30 13:05:39 2015	(r290194)
@@ -3878,12 +3878,10 @@ RetryLookup:;
 		vm_map_unlock_read(map);
 		return (KERN_PROTECTION_FAILURE);
 	}
-	if ((entry->eflags & MAP_ENTRY_USER_WIRED) &&
-	    (entry->eflags & MAP_ENTRY_COW) &&
-	    (fault_type & VM_PROT_WRITE)) {
-		vm_map_unlock_read(map);
-		return (KERN_PROTECTION_FAILURE);
-	}
+	KASSERT((prot & VM_PROT_WRITE) == 0 || (entry->eflags &
+	    (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY)) !=
+	    (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY),
+	    ("entry %p flags %x", entry, entry->eflags));
 	if ((fault_typea & VM_PROT_COPY) != 0 &&
 	    (entry->max_protection & VM_PROT_WRITE) == 0 &&
 	    (entry->eflags & MAP_ENTRY_COW) == 0) {
@@ -4037,10 +4035,6 @@ vm_map_lookup_locked(vm_map_t *var_map,	
 	fault_type &= VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
 	if ((fault_type & prot) != fault_type)
 		return (KERN_PROTECTION_FAILURE);
-	if ((entry->eflags & MAP_ENTRY_USER_WIRED) &&
-	    (entry->eflags & MAP_ENTRY_COW) &&
-	    (fault_type & VM_PROT_WRITE))
-		return (KERN_PROTECTION_FAILURE);
 
 	/*
 	 * If this page is not pageable, we have to get it for all possible

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