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Subject[PATCH 6/7] x86: pat.c introduce function to check for conflicts with existing memtypes

... to strip down loop body in reserve_memtype.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
---
arch/x86/mm/pat.c | 96 ++++++++++++++++++----------------------------------
1 files changed, 33 insertions(+), 63 deletions(-)

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 49dcd96..281ac64 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -178,6 +178,33 @@ static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
return req_type;
}

+static int chk_conflict(struct memtype *new, struct memtype *entry,
+ unsigned long *type)
+{
+ if (new->type != entry->type) {
+ if (type) {
+ new->type = entry->type;
+ *type = entry->type;
+ } else
+ goto conflict;
+ }
+
+ /* check overlaps with more than one entry in the list */
+ list_for_each_entry_continue(entry, &memtype_list, nd) {
+ if (new->end <= entry->start)
+ break;
+ else if (new->type != entry->type)
+ goto conflict;
+ }
+ return 0;
+
+ conflict:
+ printk(KERN_INFO "%s:%d conflicting memory types "
+ "%Lx-%Lx %s<->%s\n", current->comm, current->pid, new->start,
+ new->end, cattr_name(new->type), cattr_name(entry->type));
+ return -EBUSY;
+}
+
/*
* req_type typically has one of the:
* - _PAGE_CACHE_WB
@@ -254,94 +281,37 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
/* Search for existing mapping that overlaps the current range */
where = NULL;
list_for_each_entry(entry, &memtype_list, nd) {
- struct memtype *saved_ptr;
-
if (entry->start >= end) {
where = entry->nd.prev;
break;
}

if (start <= entry->start && end >= entry->start) {
- if (actual_type != entry->type && new_type) {
- actual_type = entry->type;
- *new_type = actual_type;
- new->type = actual_type;
- }
-
- if (actual_type != entry->type) {
- err = -EBUSY;
- break;
- }
-
- saved_ptr = entry;
- /*
- * Check to see whether the request overlaps more
- * than one entry in the list
- */
- list_for_each_entry_continue(entry, &memtype_list, nd) {
- if (end <= entry->start) {
- break;
- }
-
- if (actual_type != entry->type) {
- err = -EBUSY;
- break;
- }
- }
-
+ err = chk_conflict(new, entry, new_type);
if (err) {
break;
}

dprintk("Overlap at 0x%Lx-0x%Lx\n",
- saved_ptr->start, saved_ptr->end);
- where = saved_ptr->nd.prev;
+ entry->start, entry->end);
+ where = entry->nd.prev;
break;
}

if (start < entry->end) {
- if (actual_type != entry->type && new_type) {
- actual_type = entry->type;
- *new_type = actual_type;
- new->type = actual_type;
- }
-
- if (actual_type != entry->type) {
- err = -EBUSY;
- break;
- }
-
- saved_ptr = entry;
- /*
- * Check to see whether the request overlaps more
- * than one entry in the list
- */
- list_for_each_entry_continue(entry, &memtype_list, nd) {
- if (end <= entry->start) {
- break;
- }
-
- if (actual_type != entry->type) {
- err = -EBUSY;
- break;
- }
- }
-
+ err = chk_conflict(new, entry, new_type);
if (err) {
break;
}

dprintk("Overlap at 0x%Lx-0x%Lx\n",
- saved_ptr->start, saved_ptr->end);
- where = &saved_ptr->nd;
+ entry->start, entry->end);
+ where = &entry->nd;
break;
}
}

if (err) {
- printk(KERN_INFO "%s:%d conflicting memory types "
- "%Lx-%Lx %s<->%s\n", current->comm, current->pid, start,
- end, cattr_name(new->type), cattr_name(entry->type));
printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
"track %s, req %s\n",
start, end, cattr_name(new->type), cattr_name(req_type));
--
1.5.5.4




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