virtiofs: keep a list of free dax memory ranges
Divide the dax memory range into fixed size ranges (2MB for now) and put
them in a list. This will track free ranges. Once an inode requires a
free range, we will take one from here and put it in interval-tree
of ranges assigned to inode.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Peng Tao <tao.peng@linux.alibaba.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c
index 9660d01..0311060 100644
--- a/fs/fuse/dax.c
+++ b/fs/fuse/dax.c
@@ -7,20 +7,104 @@
#include "fuse_i.h"
#include <linux/dax.h>
+#include <linux/pfn_t.h>
+
+/* Default memory range size, 2MB */
+#define FUSE_DAX_SHIFT 21
+#define FUSE_DAX_SZ (1 << FUSE_DAX_SHIFT)
+#define FUSE_DAX_PAGES (FUSE_DAX_SZ / PAGE_SIZE)
+
+/** Translation information for file offsets to DAX window offsets */
+struct fuse_dax_mapping {
+ /* Will connect in fcd->free_ranges to keep track of free memory */
+ struct list_head list;
+
+ /** Position in DAX window */
+ u64 window_offset;
+
+ /** Length of mapping, in bytes */
+ loff_t length;
+};
struct fuse_conn_dax {
/* DAX device */
struct dax_device *dev;
+
+ /* DAX Window Free Ranges */
+ long nr_free_ranges;
+ struct list_head free_ranges;
};
+static void fuse_free_dax_mem_ranges(struct list_head *mem_list)
+{
+ struct fuse_dax_mapping *range, *temp;
+
+ /* Free All allocated elements */
+ list_for_each_entry_safe(range, temp, mem_list, list) {
+ list_del(&range->list);
+ kfree(range);
+ }
+}
+
void fuse_dax_conn_free(struct fuse_conn *fc)
{
- kfree(fc->dax);
+ if (fc->dax) {
+ fuse_free_dax_mem_ranges(&fc->dax->free_ranges);
+ kfree(fc->dax);
+ }
+}
+
+static int fuse_dax_mem_range_init(struct fuse_conn_dax *fcd)
+{
+ long nr_pages, nr_ranges;
+ void *kaddr;
+ pfn_t pfn;
+ struct fuse_dax_mapping *range;
+ int ret, id;
+ size_t dax_size = -1;
+ unsigned long i;
+
+ INIT_LIST_HEAD(&fcd->free_ranges);
+ id = dax_read_lock();
+ nr_pages = dax_direct_access(fcd->dev, 0, PHYS_PFN(dax_size), &kaddr,
+ &pfn);
+ dax_read_unlock(id);
+ if (nr_pages < 0) {
+ pr_debug("dax_direct_access() returned %ld\n", nr_pages);
+ return nr_pages;
+ }
+
+ nr_ranges = nr_pages/FUSE_DAX_PAGES;
+ pr_debug("%s: dax mapped %ld pages. nr_ranges=%ld\n",
+ __func__, nr_pages, nr_ranges);
+
+ for (i = 0; i < nr_ranges; i++) {
+ range = kzalloc(sizeof(struct fuse_dax_mapping), GFP_KERNEL);
+ ret = -ENOMEM;
+ if (!range)
+ goto out_err;
+
+ /* TODO: This offset only works if virtio-fs driver is not
+ * having some memory hidden at the beginning. This needs
+ * better handling
+ */
+ range->window_offset = i * FUSE_DAX_SZ;
+ range->length = FUSE_DAX_SZ;
+ list_add_tail(&range->list, &fcd->free_ranges);
+ }
+
+ fcd->nr_free_ranges = nr_ranges;
+ return 0;
+out_err:
+ /* Free All allocated elements */
+ fuse_free_dax_mem_ranges(&fcd->free_ranges);
+ return ret;
}
int fuse_dax_conn_alloc(struct fuse_conn *fc, struct dax_device *dax_dev)
{
struct fuse_conn_dax *fcd;
+ int err;
if (!dax_dev)
return 0;
@@ -30,6 +114,11 @@ int fuse_dax_conn_alloc(struct fuse_conn *fc, struct dax_device *dax_dev)
return -ENOMEM;
fcd->dev = dax_dev;
+ err = fuse_dax_mem_range_init(fcd);
+ if (err) {
+ kfree(fcd);
+ return err;
+ }
fc->dax = fcd;
return 0;