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Subject[RFC PATCH 30/60] hyper_dmabuf: free already mapped pages when error happens
Date
From: Mateusz Polrola <mateuszx.potrola@intel.com>

It is needed to freeing already-mapped pages if it gets error
before finishing mapping all pages.

Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
---
.../xen/hyper_dmabuf/xen/hyper_dmabuf_xen_shm.c | 43 +++++++++++++++++++---
1 file changed, 38 insertions(+), 5 deletions(-)

diff --git a/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_shm.c b/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_shm.c
index c03e5a0..524f75c 100644
--- a/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_shm.c
+++ b/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_shm.c
@@ -255,7 +255,7 @@ struct page ** hyper_dmabuf_xen_map_shared_pages(int lvl3_gref, int domid, int n
if (lvl3_map_ops.status) {
dev_err(hyper_dmabuf_private.device, "HYPERVISOR map grant ref failed status = %d",
lvl3_map_ops.status);
- return NULL;
+ goto error_cleanup_lvl3;
} else {
lvl3_unmap_ops.handle = lvl3_map_ops.handle;
}
@@ -263,7 +263,7 @@ struct page ** hyper_dmabuf_xen_map_shared_pages(int lvl3_gref, int domid, int n
/* Map all second level pages */
if (gnttab_alloc_pages(n_lvl2_grefs, lvl2_table_pages)) {
dev_err(hyper_dmabuf_private.device, "Cannot allocate pages\n");
- return NULL;
+ goto error_cleanup_lvl3;
}

for (i = 0; i < n_lvl2_grefs; i++) {
@@ -277,6 +277,9 @@ struct page ** hyper_dmabuf_xen_map_shared_pages(int lvl3_gref, int domid, int n
if (gnttab_unmap_refs(&lvl3_unmap_ops, NULL, &lvl3_table_page, 1)) {
dev_err(hyper_dmabuf_private.device, "xen: cannot unmap top level page\n");
return NULL;
+ } else {
+ /* Mark that page was unmapped */
+ lvl3_unmap_ops.handle = -1;
}

if (gnttab_map_refs(lvl2_map_ops, NULL, lvl2_table_pages, n_lvl2_grefs)) {
@@ -290,7 +293,7 @@ struct page ** hyper_dmabuf_xen_map_shared_pages(int lvl3_gref, int domid, int n
dev_err(hyper_dmabuf_private.device,
"HYPERVISOR map grant ref failed status = %d",
lvl2_map_ops[i].status);
- return NULL;
+ goto error_cleanup_lvl2;
} else {
lvl2_unmap_ops[i].handle = lvl2_map_ops[i].handle;
}
@@ -298,7 +301,7 @@ struct page ** hyper_dmabuf_xen_map_shared_pages(int lvl3_gref, int domid, int n

if (gnttab_alloc_pages(nents, data_pages)) {
dev_err(hyper_dmabuf_private.device, "Cannot allocate pages\n");
- return NULL;
+ goto error_cleanup_lvl2;
}

k = 0;
@@ -343,6 +346,11 @@ struct page ** hyper_dmabuf_xen_map_shared_pages(int lvl3_gref, int domid, int n
n_lvl2_grefs)) {
dev_err(hyper_dmabuf_private.device, "Cannot unmap 2nd level refs\n");
return NULL;
+ } else {
+ /* Mark that pages were unmapped */
+ for (i = 0; i < n_lvl2_grefs; i++) {
+ lvl2_unmap_ops[i].handle = -1;
+ }
}

for (i = 0; i < nents; i++) {
@@ -350,7 +358,7 @@ struct page ** hyper_dmabuf_xen_map_shared_pages(int lvl3_gref, int domid, int n
dev_err(hyper_dmabuf_private.device,
"HYPERVISOR map grant ref failed status = %d\n",
data_map_ops[i].status);
- return NULL;
+ goto error_cleanup_data;
} else {
data_unmap_ops[i].handle = data_map_ops[i].handle;
}
@@ -369,6 +377,31 @@ struct page ** hyper_dmabuf_xen_map_shared_pages(int lvl3_gref, int domid, int n

dev_dbg(hyper_dmabuf_private.device, "%s exit\n", __func__);
return data_pages;
+
+error_cleanup_data:
+ gnttab_unmap_refs(data_unmap_ops, NULL, data_pages,
+ nents);
+
+ gnttab_free_pages(nents, data_pages);
+
+error_cleanup_lvl2:
+ if (lvl2_unmap_ops[0].handle != -1)
+ gnttab_unmap_refs(lvl2_unmap_ops, NULL, lvl2_table_pages,
+ n_lvl2_grefs);
+ gnttab_free_pages(n_lvl2_grefs, lvl2_table_pages);
+
+error_cleanup_lvl3:
+ if (lvl3_unmap_ops.handle != -1)
+ gnttab_unmap_refs(&lvl3_unmap_ops, NULL, &lvl3_table_page, 1);
+ gnttab_free_pages(1, &lvl3_table_page);
+
+ kfree(lvl2_table_pages);
+ kfree(lvl2_map_ops);
+ kfree(lvl2_unmap_ops);
+ kfree(data_map_ops);
+
+
+ return NULL;
}

int hyper_dmabuf_xen_unmap_shared_pages(void **refs_info, int nents) {
--
2.7.4
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