[PATCH 17/52] virtio-fs: Retrieve shm capabilities for cache

Vivek Goyal
2018-12-10T17:12:43Z

Retrieve the capabilities needed to find the cache.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
fs/fuse/virtio_fs.c | 15 +++++++++++++++
include/uapi/linux/virtio_fs.h | 3 +++
2 files changed, 18 insertions(+)

diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index cd916943205e..60d496c16841 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -520,6 +520,8 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
phys_addr_t phys_addr;
size_t len;
int ret;
+ u8 have_cache, cache_bar;
+ u64 cache_offset, cache_len;

if (!IS_ENABLED(CONFIG_DAX_DRIVER))
return 0;
@@ -535,6 +537,19 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
if (ret < 0)
return ret;

+ have_cache = virtio_pci_find_shm_cap(pci_dev,
+ VIRTIO_FS_PCI_SHMCAP_ID_CACHE, &cache_bar,
+ &cache_offset, &cache_len);
+
+ if (!have_cache) {
+ dev_err(&vdev->dev, "%s: No cache capability\n",
+ __func__);
+ return -ENXIO;
+ } else {
+ dev_notice(&vdev->dev, "Cache bar: %d len: 0x%llx @ 0x%llx\n",
+ cache_bar, cache_len, cache_offset);
+ }
+
/* TODO handle case where device doesn't expose BAR? */
ret = pci_request_region(pci_dev, VIRTIO_FS_WINDOW_BAR,
"virtio-fs-window");
diff --git a/include/uapi/linux/virtio_fs.h b/include/uapi/linux/virtio_fs.h
index 48f3590dcfbe..65a9d4a0dac0 100644
--- a/include/uapi/linux/virtio_fs.h
+++ b/include/uapi/linux/virtio_fs.h
@@ -38,4 +38,7 @@ struct virtio_fs_config {
__u32 num_queues;
} __attribute__((packed));

+/* For the id field in virtio_pci_shm_cap */
+#define VIRTIO_FS_PCI_SHMCAP_ID_CACHE 0
+
#endif /* _UAPI_LINUX_VIRTIO_FS_H */
--
2.13.6