From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
This patch adds a new data arg to region tracking functions.
region_chg function will merge regions only if data arg match
otherwise it will create a new region to map the range.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
include/linux/region.h | 20 ++++--
mm/region.c | 177 ++++++++++++++++++++++++++++++++----------------
2 files changed, 132 insertions(+), 65 deletions(-)
diff --git a/include/linux/region.h b/include/linux/region.h
index a8a5b46..609e24c 100644
--- a/include/linux/region.h
+++ b/include/linux/region.h
@@ -16,13 +16,21 @@
#define _LINUX_REGION_H
struct file_region {
+ unsigned long from, to;
+ unsigned long data;
struct list_head link;
- long from;
- long to;
};
-extern long region_add(struct list_head *head, long from, long to);
-extern long region_chg(struct list_head *head, long from, long to);
-extern long region_truncate(struct list_head *head, long end);
-extern long region_count(struct list_head *head, long from, long to);
+extern long region_chg(struct list_head *head, unsigned long from,
+ unsigned long to, unsigned long data);
+extern void region_add(struct list_head *head, unsigned long from,
+ unsigned long to, unsigned long data);
+extern long region_truncate_range(struct list_head *head, unsigned long from,
+ unsigned long end);
+static inline long region_truncate(struct list_head *head, unsigned long from)
+{
+ return region_truncate_range(head, from, ULONG_MAX);
+}
+extern long region_count(struct list_head *head, unsigned long from,
+ unsigned long to);
#endif
diff --git a/mm/region.c b/mm/region.c
index ab59fe7..e547631 100644
--- a/mm/region.c
+++ b/mm/region.c
@@ -18,66 +18,46 @@
#include <linux/list.h>
#include <linux/region.h>
-long region_add(struct list_head *head, long from, long to)
+long region_chg(struct list_head *head, unsigned long from,
+ unsigned long to, unsigned long data)
{
- struct file_region *rg, *nrg, *trg;
-
- /* Locate the region we are either in or before. */
- list_for_each_entry(rg, head, link)
- if (from <= rg->to)
- break;
-
- /* Round our left edge to the current segment if it encloses us. */
- if (from > rg->from)
- from = rg->from;
-
- /* Check for and consume any regions we now overlap with. */
- nrg = rg;
- list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
- if (&rg->link == head)
- break;
- if (rg->from > to)
- break;
-
- /* If this area reaches higher then extend our area to
- * include it completely. If this is not the first area
- * which we intend to reuse, free it. */
- if (rg->to > to)
- to = rg->to;
- if (rg != nrg) {
- list_del(&rg->link);
- kfree(rg);
- }
- }
- nrg->from = from;
- nrg->to = to;
- return 0;
-}
-
-long region_chg(struct list_head *head, long from, long to)
-{
- struct file_region *rg, *nrg;
long chg = 0;
+ struct file_region *rg, *nrg, *trg;
/* Locate the region we are before or in. */
list_for_each_entry(rg, head, link)
if (from <= rg->to)
break;
-
- /* If we are below the current region then a new region is required.
+ /*
+ * If we are below the current region then a new region is required.
* Subtle, allocate a new region at the position but make it zero
- * size such that we can guarantee to record the reservation. */
+ * size such that we can guarantee to record the reservation.
+ */
if (&rg->link == head || to < rg->from) {
nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
if (!nrg)
return -ENOMEM;
nrg->from = from;
- nrg->to = from;
+ nrg->to = from;
+ nrg->data = data;
INIT_LIST_HEAD(&nrg->link);
list_add(&nrg->link, rg->link.prev);
-
return to - from;
}
+ /*
+ * from rg->from to rg->to
+ */
+ if (from < rg->from && data != rg->data) {
+ /* we need to allocate a new region */
+ nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
+ if (!nrg)
+ return -ENOMEM;
+ nrg->from = from;
+ nrg->to = from;
+ nrg->data = data;
+ INIT_LIST_HEAD(&nrg->link);
+ list_add(&nrg->link, rg->link.prev);
+ }
/* Round our left edge to the current segment if it encloses us. */
if (from > rg->from)
@@ -85,15 +65,28 @@ long region_chg(struct list_head *head, long from, long to)
chg = to - from;
/* Check for and consume any regions we now overlap with. */
- list_for_each_entry(rg, rg->link.prev, link) {
+ list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
if (&rg->link == head)
break;
if (rg->from > to)
return chg;
-
- /* We overlap with this area, if it extends further than
- * us then we must extend ourselves. Account for its
- * existing reservation. */
+ /*
+ * rg->from from rg->to to
+ */
+ if (to > rg->to && data != rg->data) {
+ /* we need to allocate a new region */
+ nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
+ if (!nrg)
+ return -ENOMEM;
+ nrg->from = rg->to;
+ nrg->to = rg->to;
+ nrg->data = data;
+ INIT_LIST_HEAD(&nrg->link);
+ list_add(&nrg->link, &rg->link);
+ }
+ /*
+ * update charge
+ */
if (rg->to > to) {
chg += rg->to - to;
to = rg->to;
@@ -103,29 +96,96 @@ long region_chg(struct list_head *head, long from, long to)
return chg;
}
-long region_truncate(struct list_head *head, long end)
+void region_add(struct list_head *head, unsigned long from,
+ unsigned long to, unsigned long data)
+{
+ struct file_region *rg, *nrg, *trg;
+
+ /* Locate the region we are before or in. */
+ list_for_each_entry(rg, head, link)
+ if (from <= rg->to)
+ break;
+
+ list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
+
+ if (rg->from > to)
+ return;
+ if (&rg->link == head)
+ return;
+
+ /*FIXME!! this can possibly delete few regions */
+ /* We need to worry only if we match data */
+ if (rg->data == data) {
+ if (from < rg->from)
+ rg->from = from;
+ if (to > rg->to) {
+ /* if we are the last entry */
+ if (rg->link.next == head) {
+ rg->to = to;
+ break;
+ } else {
+ nrg = list_entry(rg->link.next,
+ typeof(*nrg), link);
+ rg->to = nrg->from;
+ }
+ }
+ }
+ from = rg->to;
+ }
+}
+
+long region_truncate_range(struct list_head *head, unsigned long from,
+ unsigned long to)
{
- struct file_region *rg, *trg;
long chg = 0;
+ struct file_region *rg, *trg;
/* Locate the region we are either in or before. */
list_for_each_entry(rg, head, link)
- if (end <= rg->to)
+ if (from <= rg->to)
break;
if (&rg->link == head)
return 0;
/* If we are in the middle of a region then adjust it. */
- if (end > rg->from) {
- chg = rg->to - end;
- rg->to = end;
+ if (from > rg->from) {
+ if (to < rg->to) {
+ struct file_region *nrg;
+ /* rf->from from to rg->to */
+ nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
+ /*
+ * If we fail to allocate we return the
+ * with the 0 charge . Later a complete
+ * truncate will reclaim the left over space
+ */
+ if (!nrg)
+ return 0;
+ nrg->from = to;
+ nrg->to = rg->to;
+ nrg->data = rg->data;
+ INIT_LIST_HEAD(&nrg->link);
+ list_add(&nrg->link, &rg->link);
+
+ /* Adjust the rg entry */
+ rg->to = from;
+ chg = to - from;
+ return chg;
+ }
+ chg = rg->to - from;
+ rg->to = from;
rg = list_entry(rg->link.next, typeof(*rg), link);
}
-
- /* Drop any remaining regions. */
+ /* Drop any remaining regions till to */
list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
+ if (rg->from >= to)
+ break;
if (&rg->link == head)
break;
+ if (rg->to > to) {
+ chg += to - rg->from;
+ rg->from = to;
+ return chg;
+ }
chg += rg->to - rg->from;
list_del(&rg->link);
kfree(rg);
@@ -133,10 +193,10 @@ long region_truncate(struct list_head *head, long end)
return chg;
}
-long region_count(struct list_head *head, long from, long to)
+long region_count(struct list_head *head, unsigned long from, unsigned long to)
{
- struct file_region *rg;
long chg = 0;
+ struct file_region *rg;
/* Locate each segment we overlap with, and count that overlap. */
list_for_each_entry(rg, head, link) {
@@ -153,6 +213,5 @@ long region_count(struct list_head *head, long from, long to)
chg += seg_to - seg_from;
}
-
return chg;
}
--
1.7.9
--
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