[ndctl PATCH 2/4] libdaxctl: tie mapping cache lifetime to the device

[Alison Schofield]

Cached mappings are not freed when a device is destroyed or invalidated
when its ranges change. This leaks memory and can leave callers using
obsolete physical address ranges, potentially operating on memory blocks
that no longer belong to the device.

Free mappings on device destruction and invalidate the cache when device
ranges may have changed.

Fixes: 5a31bf710399 ("libdaxctl: add mapping iterator APIs")
Fixes: 52a2653098a5 ("libdaxctl: add daxctl_dev_set_mapping()")
Signed-off-by: Alison Schofield <alison.schofi...@intel.com>
---
 daxctl/lib/libdaxctl.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
index f630f4791f59..f7cbf3fa12e7 100644
--- a/daxctl/lib/libdaxctl.c
+++ b/daxctl/lib/libdaxctl.c
@@ -241,6 +241,7 @@ static void free_dev(struct daxctl_dev *dev, struct 
list_head *head)
        free(dev->dev_buf);
        free(dev->dev_path);
        free_mem(dev);
+       free_mappings(dev);
        free(dev);
 }
 
@@ -593,14 +594,15 @@ static void *add_dax_dev(void *parent, int id, const char 
*daxdev_base)
        else
                dev->target_node = -1;
 
+       dev->num_mappings = -1;
+       list_head_init(&dev->mappings);
+
        daxctl_dev_foreach(region, dev_dup)
                if (dev_dup->id == dev->id) {
                        free_dev(dev, NULL);
                        free(path);
                        return dev_dup;
                }
-       dev->num_mappings = -1;
-       list_head_init(&dev->mappings);
        list_add(&region->devices, &dev->list);
        free(path);
        return dev;
@@ -1186,6 +1188,7 @@ DAXCTL_EXPORT int daxctl_dev_set_size(struct daxctl_dev 
*dev, unsigned long long
        }
 
        sprintf(buf, "%#llx\n", size);
+       free_mappings(dev);
        if (sysfs_write_attr(ctx, path, buf) < 0) {
                err(ctx, "%s: failed to set size\n",
                                daxctl_dev_get_devname(dev));
@@ -1242,6 +1245,7 @@ DAXCTL_EXPORT int daxctl_dev_set_mapping(struct 
daxctl_dev *dev,
        }
 
        sprintf(buf, "%#llx-%#llx\n", start, end);
+       free_mappings(dev);
        if (sysfs_write_attr(ctx, path, buf) < 0) {
                err(ctx, "%s: failed to set mapping\n",
                                daxctl_dev_get_devname(dev));
-- 
2.37.3