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

[Vivek Goyal]

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

Signed-off-by: Dr. David Alan Gilbert <dgilb...@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