[PATCH 18/52] virtio-fs: Map cache using the values from the capabilities

Vivek Goyal
2018-12-10T17:12:44Z

Instead of assuming we had the fixed bar for the cache, use the
value from the capabilities.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
fs/fuse/virtio_fs.c | 32 +++++++++++++++++---------------
1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index 60d496c16841..55bac1465536 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -14,11 +14,6 @@
#include <uapi/linux/virtio_pci.h>
#include "fuse_i.h"

-enum {
- /* PCI BAR number of the virtio-fs DAX window */
- VIRTIO_FS_WINDOW_BAR = 2,
-};
-
/* List of virtio-fs device instances and a lock for the list */
static DEFINE_MUTEX(virtio_fs_mutex);
static LIST_HEAD(virtio_fs_instances);
@@ -518,7 +513,7 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
struct dev_pagemap *pgmap;
struct pci_dev *pci_dev;
phys_addr_t phys_addr;
- size_t len;
+ size_t bar_len;
int ret;
u8 have_cache, cache_bar;
u64 cache_offset, cache_len;
@@ -551,17 +546,13 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
}

/* TODO handle case where device doesn't expose BAR? */
- ret = pci_request_region(pci_dev, VIRTIO_FS_WINDOW_BAR,
- "virtio-fs-window");
+ ret = pci_request_region(pci_dev, cache_bar, "virtio-fs-window");
if (ret < 0) {
dev_err(&vdev->dev, "%s: failed to request window BAR\n",
__func__);
return ret;
}

- phys_addr = pci_resource_start(pci_dev, VIRTIO_FS_WINDOW_BAR);
- len = pci_resource_len(pci_dev, VIRTIO_FS_WINDOW_BAR);
-
mi = devm_kzalloc(&pci_dev->dev, sizeof(*mi), GFP_KERNEL);
if (!mi)
return -ENOMEM;
@@ -586,6 +577,17 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
pgmap->ref = &mi->ref;
pgmap->type = MEMORY_DEVICE_FS_DAX;

+ phys_addr = pci_resource_start(pci_dev, cache_bar);
+ bar_len = pci_resource_len(pci_dev, cache_bar);
+
+ if (cache_offset + cache_len > bar_len) {
+ dev_err(&vdev->dev,
+ "%s: cache bar shorter than cap offset+len\n",
+ __func__);
+ return -EINVAL;
+ }
+ phys_addr += cache_offset;
+
/* Ideally we would directly use the PCI BAR resource but
* devm_memremap_pages() wants its own copy in pgmap. So
* initialize a struct resource from scratch (only the start
@@ -594,7 +596,7 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
pgmap->res = (struct resource){
.name = "virtio-fs dax window",
.start = phys_addr,
- .end = phys_addr + len,
+ .end = phys_addr + cache_len,
};

fs->window_kaddr = devm_memremap_pages(&pci_dev->dev, pgmap);
@@ -607,10 +609,10 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
return ret;

fs->window_phys_addr = phys_addr;
- fs->window_len = len;
+ fs->window_len = cache_len;

- dev_dbg(&vdev->dev, "%s: window kaddr 0x%px phys_addr 0x%llx len %zu\n",
- __func__, fs->window_kaddr, phys_addr, len);
+ dev_dbg(&vdev->dev, "%s: cache kaddr 0x%px phys_addr 0x%llx len %llx\n",
+ __func__, fs->window_kaddr, phys_addr, cache_len);

fs->dax_dev = alloc_dax(fs, NULL, &virtio_fs_dax_ops);
if (!fs->dax_dev)
--
2.13.6