Author: dougm
Date: Tue Oct  8 07:14:21 2019
New Revision: 353298
URL: https://svnweb.freebsd.org/changeset/base/353298

Log:
  Define macro VM_MAP_ENTRY_FOREACH for enumerating the entries in a vm_map.
  In case the implementation ever changes from using a chain of next pointers,
  then changing the macro definition will be necessary, but changing all the
  files that iterate over vm_map entries will not.
  
  Drop a counter in vm_object.c that would have an effect only if the
  vm_map entry count was wrong.
  
  Discussed with: alc
  Reviewed by: markj
  Tested by: pho (earlier version)
  Differential Revision:        https://reviews.freebsd.org/D21882

Modified:
  head/sys/compat/linprocfs/linprocfs.c
  head/sys/dev/hwpmc/hwpmc_mod.c
  head/sys/fs/procfs/procfs_map.c
  head/sys/fs/tmpfs/tmpfs_vfsops.c
  head/sys/kern/imgact_elf.c
  head/sys/kern/kern_proc.c
  head/sys/kern/sys_process.c
  head/sys/security/mac/mac_process.c
  head/sys/vm/swap_pager.c
  head/sys/vm/vm_map.h
  head/sys/vm/vm_object.c
  head/sys/vm/vm_pageout.c
  head/sys/vm/vm_swapout.c

Modified: head/sys/compat/linprocfs/linprocfs.c
==============================================================================
--- head/sys/compat/linprocfs/linprocfs.c       Tue Oct  8 02:36:53 2019        
(r353297)
+++ head/sys/compat/linprocfs/linprocfs.c       Tue Oct  8 07:14:21 2019        
(r353298)
@@ -1174,8 +1174,7 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
                l_map_str = l32_map_str;
        map = &vm->vm_map;
        vm_map_lock_read(map);
-       for (entry = map->header.next; entry != &map->header;
-           entry = entry->next) {
+       VM_MAP_ENTRY_FOREACH(entry, map) {
                name = "";
                freename = NULL;
                if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)

Modified: head/sys/dev/hwpmc/hwpmc_mod.c
==============================================================================
--- head/sys/dev/hwpmc/hwpmc_mod.c      Tue Oct  8 02:36:53 2019        
(r353297)
+++ head/sys/dev/hwpmc/hwpmc_mod.c      Tue Oct  8 07:14:21 2019        
(r353298)
@@ -1884,7 +1884,7 @@ pmc_log_process_mappings(struct pmc_owner *po, struct 
        map = &vm->vm_map;
        vm_map_lock_read(map);
 
-       for (entry = map->header.next; entry != &map->header; entry = 
entry->next) {
+       VM_MAP_ENTRY_FOREACH(entry, map) {
 
                if (entry == NULL) {
                        PMCDBG2(LOG,OPS,2, "hwpmc: vm_map entry unexpectedly "
@@ -1988,7 +1988,7 @@ pmc_log_process_mappings(struct pmc_owner *po, struct 
                 * new lookup for this entry.  If there is no entry
                 * for this address range, vm_map_lookup_entry() will
                 * return the previous one, so we always want to go to
-                * entry->next on the next loop iteration.
+                * the next entry on the next loop iteration.
                 * 
                 * There is an edge condition here that can occur if
                 * there is no entry at or before this address.  In

Modified: head/sys/fs/procfs/procfs_map.c
==============================================================================
--- head/sys/fs/procfs/procfs_map.c     Tue Oct  8 02:36:53 2019        
(r353297)
+++ head/sys/fs/procfs/procfs_map.c     Tue Oct  8 07:14:21 2019        
(r353298)
@@ -118,8 +118,7 @@ procfs_doprocmap(PFS_FILL_ARGS)
                return (ESRCH);
        map = &vm->vm_map;
        vm_map_lock_read(map);
-       for (entry = map->header.next; entry != &map->header;
-            entry = entry->next) {
+       VM_MAP_ENTRY_FOREACH(entry, map) {
                if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
                        continue;
 

Modified: head/sys/fs/tmpfs/tmpfs_vfsops.c
==============================================================================
--- head/sys/fs/tmpfs/tmpfs_vfsops.c    Tue Oct  8 02:36:53 2019        
(r353297)
+++ head/sys/fs/tmpfs/tmpfs_vfsops.c    Tue Oct  8 07:14:21 2019        
(r353298)
@@ -262,8 +262,7 @@ again:
                vm_map_lock(map);
                if (map->busy)
                        vm_map_wait_busy(map);
-               for (entry = map->header.next; entry != &map->header;
-                   entry = entry->next) {
+               VM_MAP_ENTRY_FOREACH(entry, map) {
                        if ((entry->eflags & (MAP_ENTRY_GUARD |
                            MAP_ENTRY_IS_SUB_MAP | MAP_ENTRY_COW)) != 0 ||
                            (entry->max_protection & VM_PROT_WRITE) == 0)

Modified: head/sys/kern/imgact_elf.c
==============================================================================
--- head/sys/kern/imgact_elf.c  Tue Oct  8 02:36:53 2019        (r353297)
+++ head/sys/kern/imgact_elf.c  Tue Oct  8 07:14:21 2019        (r353298)
@@ -1738,8 +1738,7 @@ each_dumpable_segment(struct thread *td, segment_callb
        boolean_t ignore_entry;
 
        vm_map_lock_read(map);
-       for (entry = map->header.next; entry != &map->header;
-           entry = entry->next) {
+       VM_MAP_ENTRY_FOREACH(entry, map) {
                /*
                 * Don't dump inaccessible mappings, deal with legacy
                 * coredump mode.

Modified: head/sys/kern/kern_proc.c
==============================================================================
--- head/sys/kern/kern_proc.c   Tue Oct  8 02:36:53 2019        (r353297)
+++ head/sys/kern/kern_proc.c   Tue Oct  8 07:14:21 2019        (r353298)
@@ -2239,8 +2239,7 @@ sysctl_kern_proc_ovmmap(SYSCTL_HANDLER_ARGS)
 
        map = &vm->vm_map;
        vm_map_lock_read(map);
-       for (entry = map->header.next; entry != &map->header;
-           entry = entry->next) {
+       VM_MAP_ENTRY_FOREACH(entry, map) {
                vm_object_t obj, tobj, lobj;
                vm_offset_t addr;
 
@@ -2455,8 +2454,7 @@ kern_proc_vmmap_out(struct proc *p, struct sbuf *sb, s
        error = 0;
        map = &vm->vm_map;
        vm_map_lock_read(map);
-       for (entry = map->header.next; entry != &map->header;
-           entry = entry->next) {
+       VM_MAP_ENTRY_FOREACH(entry, map) {
                if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
                        continue;
 

Modified: head/sys/kern/sys_process.c
==============================================================================
--- head/sys/kern/sys_process.c Tue Oct  8 02:36:53 2019        (r353297)
+++ head/sys/kern/sys_process.c Tue Oct  8 07:14:21 2019        (r353298)
@@ -382,21 +382,18 @@ ptrace_vm_entry(struct thread *td, struct proc *p, str
        vm_map_lock_read(map);
 
        do {
-               entry = map->header.next;
+               KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
+                   ("Submap in map header"));
                index = 0;
-               while (index < pve->pve_entry && entry != &map->header) {
-                       entry = entry->next;
+               VM_MAP_ENTRY_FOREACH(entry, map) {
+                       if (index >= pve->pve_entry &&
+                           (entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
+                               break;
                        index++;
                }
-               if (index != pve->pve_entry) {
+               if (index < pve->pve_entry) {
                        error = EINVAL;
                        break;
-               }
-               KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
-                   ("Submap in map header"));
-               while ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
-                       entry = entry->next;
-                       index++;
                }
                if (entry == &map->header) {
                        error = ENOENT;

Modified: head/sys/security/mac/mac_process.c
==============================================================================
--- head/sys/security/mac/mac_process.c Tue Oct  8 02:36:53 2019        
(r353297)
+++ head/sys/security/mac/mac_process.c Tue Oct  8 07:14:21 2019        
(r353298)
@@ -264,7 +264,7 @@ mac_proc_vm_revoke_recurse(struct thread *td, struct u
                return;
 
        vm_map_lock(map);
-       for (vme = map->header.next; vme != &map->header; vme = vme->next) {
+       VM_MAP_ENTRY_FOREACH(vme, map) {
                if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
                        mac_proc_vm_revoke_recurse(td, cred,
                            vme->object.sub_map);

Modified: head/sys/vm/swap_pager.c
==============================================================================
--- head/sys/vm/swap_pager.c    Tue Oct  8 02:36:53 2019        (r353297)
+++ head/sys/vm/swap_pager.c    Tue Oct  8 07:14:21 2019        (r353298)
@@ -2621,7 +2621,7 @@ vmspace_swap_count(struct vmspace *vmspace)
        map = &vmspace->vm_map;
        count = 0;
 
-       for (cur = map->header.next; cur != &map->header; cur = cur->next) {
+       VM_MAP_ENTRY_FOREACH(cur, map) {
                if ((cur->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
                        continue;
                object = cur->object.vm_object;

Modified: head/sys/vm/vm_map.h
==============================================================================
--- head/sys/vm/vm_map.h        Tue Oct  8 02:36:53 2019        (r353297)
+++ head/sys/vm/vm_map.h        Tue Oct  8 07:14:21 2019        (r353298)
@@ -416,6 +416,10 @@ int vm_map_lookup_locked(vm_map_t *, vm_offset_t, vm_p
     vm_pindex_t *, vm_prot_t *, boolean_t *);
 void vm_map_lookup_done (vm_map_t, vm_map_entry_t);
 boolean_t vm_map_lookup_entry (vm_map_t, vm_offset_t, vm_map_entry_t *);
+#define VM_MAP_ENTRY_FOREACH(it, map)                  \
+       for ((it) = (map)->header.next;         \
+           (it) != &(map)->header;             \
+           (it) = (it)->next)
 int vm_map_protect (vm_map_t, vm_offset_t, vm_offset_t, vm_prot_t, boolean_t);
 int vm_map_remove (vm_map_t, vm_offset_t, vm_offset_t);
 void vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev,

Modified: head/sys/vm/vm_object.c
==============================================================================
--- head/sys/vm/vm_object.c     Tue Oct  8 02:36:53 2019        (r353297)
+++ head/sys/vm/vm_object.c     Tue Oct  8 07:14:21 2019        (r353298)
@@ -2376,29 +2376,22 @@ _vm_object_in_map(vm_map_t map, vm_object_t object, vm
        vm_map_t tmpm;
        vm_map_entry_t tmpe;
        vm_object_t obj;
-       int entcount;
 
        if (map == 0)
                return 0;
 
        if (entry == 0) {
-               tmpe = map->header.next;
-               entcount = map->nentries;
-               while (entcount-- && (tmpe != &map->header)) {
+               VM_MAP_ENTRY_FOREACH(tmpe, map) {
                        if (_vm_object_in_map(map, object, tmpe)) {
                                return 1;
                        }
-                       tmpe = tmpe->next;
                }
        } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
                tmpm = entry->object.sub_map;
-               tmpe = tmpm->header.next;
-               entcount = tmpm->nentries;
-               while (entcount-- && tmpe != &tmpm->header) {
+               VM_MAP_ENTRY_FOREACH(tmpe, tmpm) {
                        if (_vm_object_in_map(tmpm, object, tmpe)) {
                                return 1;
                        }
-                       tmpe = tmpe->next;
                }
        } else if ((obj = entry->object.vm_object) != NULL) {
                for (; obj; obj = obj->backing_object)

Modified: head/sys/vm/vm_pageout.c
==============================================================================
--- head/sys/vm/vm_pageout.c    Tue Oct  8 02:36:53 2019        (r353297)
+++ head/sys/vm/vm_pageout.c    Tue Oct  8 07:14:21 2019        (r353298)
@@ -1783,8 +1783,7 @@ vm_pageout_oom_pagecount(struct vmspace *vmspace)
        KASSERT(!map->system_map, ("system map"));
        sx_assert(&map->lock, SA_LOCKED);
        res = 0;
-       for (entry = map->header.next; entry != &map->header;
-           entry = entry->next) {
+       VM_MAP_ENTRY_FOREACH(entry, map) {
                if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
                        continue;
                obj = entry->object.vm_object;

Modified: head/sys/vm/vm_swapout.c
==============================================================================
--- head/sys/vm/vm_swapout.c    Tue Oct  8 02:36:53 2019        (r353297)
+++ head/sys/vm/vm_swapout.c    Tue Oct  8 07:14:21 2019        (r353298)
@@ -284,8 +284,7 @@ vm_swapout_map_deactivate_pages(vm_map_t map, long des
         * first, search out the biggest object, and try to free pages from
         * that.
         */
-       tmpe = map->header.next;
-       while (tmpe != &map->header) {
+       VM_MAP_ENTRY_FOREACH(tmpe, map) {
                if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
                        obj = tmpe->object.vm_object;
                        if (obj != NULL && VM_OBJECT_TRYRLOCK(obj)) {
@@ -302,7 +301,6 @@ vm_swapout_map_deactivate_pages(vm_map_t map, long des
                }
                if (tmpe->wired_count > 0)
                        nothingwired = FALSE;
-               tmpe = tmpe->next;
        }
 
        if (bigobj != NULL) {
@@ -313,8 +311,7 @@ vm_swapout_map_deactivate_pages(vm_map_t map, long des
         * Next, hunt around for other pages to deactivate.  We actually
         * do this search sort of wrong -- .text first is not the best idea.
         */
-       tmpe = map->header.next;
-       while (tmpe != &map->header) {
+       VM_MAP_ENTRY_FOREACH(tmpe, map) {
                if (pmap_resident_count(vm_map_pmap(map)) <= desired)
                        break;
                if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
@@ -326,7 +323,6 @@ vm_swapout_map_deactivate_pages(vm_map_t map, long des
                                VM_OBJECT_RUNLOCK(obj);
                        }
                }
-               tmpe = tmpe->next;
        }
 
        /*
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