Jan Beulich
2012-May-10 15:17 UTC
[PATCH 1/4] linux-2.6.18: fix VM_FOREIGN users after c/s 878:eba6fe6d8d53
The level of indirection got increased by the blktap2 changes, yet
existing users were not properly updated. While c/s 901:9242c5b965c1
did so for a specific case in blktap, this was incomplete and left out
gntdev altogether.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/drivers/xen/blktap/blktap.c
+++ b/drivers/xen/blktap/blktap.c
@@ -120,7 +120,7 @@ typedef struct tap_blkif {
[req id, idx] tuple */
blkif_t *blkif; /*Associate blkif with tapdev */
struct domid_translate_ext trans; /*Translation from domid to bus. */
- struct vm_foreign_map foreign_map; /*Mapping page */
+ struct vm_foreign_map *foreign_maps; /*Mapping pages */
} tap_blkif_t;
static struct tap_blkif *tapfds[MAX_TAP_DEV];
@@ -329,7 +329,7 @@ static pte_t blktap_clear_pte(struct vm_
pg = idx_to_page(mmap_idx, pending_idx, seg);
ClearPageReserved(pg);
- info->foreign_map.map[offset + RING_PAGES] = NULL;
+ info->foreign_maps->map[offset + RING_PAGES] = NULL;
khandle = &pending_handle(mmap_idx, pending_idx, seg);
@@ -377,12 +377,17 @@ static pte_t blktap_clear_pte(struct vm_
static void blktap_vma_open(struct vm_area_struct *vma)
{
tap_blkif_t *info;
+ unsigned long idx;
+ struct vm_foreign_map *foreign_map;
+
if (vma->vm_file == NULL)
return;
info = vma->vm_file->private_data;
- vma->vm_private_data - &info->foreign_map.map[(vma->vm_start -
info->rings_vstart) >> PAGE_SHIFT];
+ idx = (vma->vm_start - info->rings_vstart) >> PAGE_SHIFT;
+ foreign_map = &info->foreign_maps[idx];
+ foreign_map->map = &info->foreign_maps->map[idx];
+ vma->vm_private_data = foreign_map;
}
/* tricky part
@@ -392,7 +397,6 @@ static void blktap_vma_open(struct vm_ar
*/
static void blktap_vma_close(struct vm_area_struct *vma)
{
- tap_blkif_t *info;
struct vm_area_struct *next = vma->vm_next;
if (next == NULL ||
@@ -402,9 +406,7 @@ static void blktap_vma_close(struct vm_a
vma->vm_file != next->vm_file)
return;
- info = vma->vm_file->private_data;
- next->vm_private_data - &info->foreign_map.map[(next->vm_start -
info->rings_vstart) >> PAGE_SHIFT];
+ blktap_vma_open(next);
}
static struct vm_operations_struct blktap_vm_ops = {
@@ -640,8 +642,9 @@ static int blktap_release(struct inode *
mm = xchg(&info->mm, NULL);
if (mm)
mmput(mm);
- kfree(info->foreign_map.map);
- info->foreign_map.map = NULL;
+ kfree(info->foreign_maps->map);
+ kfree(info->foreign_maps);
+ info->foreign_maps = NULL;
/* Free the ring page. */
ClearPageReserved(virt_to_page(info->ufe_ring.sring));
@@ -730,14 +733,19 @@ static int blktap_mmap(struct file *filp
}
/* Mark this VM as containing foreign pages, and set up mappings. */
- info->foreign_map.map = kzalloc(((vma->vm_end - vma->vm_start)
>> PAGE_SHIFT) *
- sizeof(*info->foreign_map.map), GFP_KERNEL);
- if (info->foreign_map.map == NULL) {
+ info->foreign_maps = kcalloc(size, sizeof(*info->foreign_maps),
+ GFP_KERNEL);
+ if (info->foreign_maps)
+ info->foreign_maps->map + kcalloc(size,
sizeof(*info->foreign_maps->map),
+ GFP_KERNEL);
+ if (!info->foreign_maps || !info->foreign_maps->map) {
+ kfree(info->foreign_maps);
WPRINTK("Couldn''t alloc VM_FOREIGN map.\n");
goto fail;
}
- vma->vm_private_data = &info->foreign_map;
+ vma->vm_private_data = info->foreign_maps;
vma->vm_flags |= VM_FOREIGN;
vma->vm_flags |= VM_DONTCOPY;
@@ -1242,7 +1250,7 @@ static int blktap_read_ufe_ring(tap_blki
pg = idx_to_page(mmap_idx, pending_idx, j);
ClearPageReserved(pg);
offset = (uvaddr - info->rings_vstart) >> PAGE_SHIFT;
- info->foreign_map.map[offset] = NULL;
+ info->foreign_maps->map[offset] = NULL;
}
fast_flush_area(pending_req, pending_idx, usr_idx, info);
make_response(blkif, pending_req->id, res.operation,
@@ -1530,7 +1538,7 @@ static void dispatch_rw_block_io(blkif_t
FOREIGN_FRAME(map[i].dev_bus_addr
>> PAGE_SHIFT));
offset = (uvaddr - info->rings_vstart) >> PAGE_SHIFT;
- info->foreign_map.map[offset] = pg;
+ info->foreign_maps->map[offset] = pg;
}
} else {
for (i = 0; i < nseg; i++) {
@@ -1556,7 +1564,7 @@ static void dispatch_rw_block_io(blkif_t
offset = (uvaddr - info->rings_vstart) >> PAGE_SHIFT;
pg = idx_to_page(mmap_idx, pending_idx, i);
- info->foreign_map.map[offset] = pg;
+ info->foreign_maps->map[offset] = pg;
}
}
--- a/drivers/xen/gntdev/gntdev.c
+++ b/drivers/xen/gntdev/gntdev.c
@@ -459,6 +459,7 @@ static int gntdev_mmap (struct file *fli
int i;
struct page *page;
gntdev_file_private_data_t *private_data = flip->private_data;
+ struct vm_foreign_map *foreign_map;
if (unlikely(!private_data)) {
printk(KERN_ERR "File''s private data is NULL.\n");
@@ -487,6 +488,14 @@ static int gntdev_mmap (struct file *fli
return -EINVAL;
}
+ foreign_map = kmalloc(sizeof(*foreign_map), GFP_KERNEL);
+ if (!foreign_map) {
+ printk(KERN_ERR "Couldn''t allocate mapping structure for VM
"
+ "area.\n");
+ return -ENOMEM;
+ }
+ foreign_map->map = &private_data->foreign_pages[slot_index];
+
/* Slots must be in the NOT_YET_MAPPED state. */
down_write(&private_data->grants_sem);
for (i = 0; i < size; ++i) {
@@ -496,6 +505,7 @@ static int gntdev_mmap (struct file *fli
"state (%d).\n", slot_index + i,
private_data->grants[slot_index + i].state);
up_write(&private_data->grants_sem);
+ kfree(foreign_map);
return -EINVAL;
}
}
@@ -504,14 +514,8 @@ static int gntdev_mmap (struct file *fli
vma->vm_ops = &gntdev_vmops;
/* The VM area contains pages from another VM. */
+ vma->vm_private_data = foreign_map;
vma->vm_flags |= VM_FOREIGN;
- vma->vm_private_data = kzalloc(size * sizeof(struct page *),
- GFP_KERNEL);
- if (vma->vm_private_data == NULL) {
- printk(KERN_ERR "Couldn''t allocate mapping structure for VM
"
- "area.\n");
- return -ENOMEM;
- }
/* This flag prevents Bad PTE errors when the memory is unmapped. */
vma->vm_flags |= VM_RESERVED;
@@ -567,11 +571,6 @@ static int gntdev_mmap (struct file *fli
goto undo_map_out;
}
- /* Store a reference to the page that will be mapped into user
- * space.
- */
- ((struct page **) vma->vm_private_data)[i] = page;
-
/* Mark mapped page as reserved. */
SetPageReserved(page);
@@ -676,7 +675,8 @@ undo_map_out:
* by do_mmap_pgoff(), which will eventually call gntdev_clear_pte().
* All we need to do here is free the vma_private_data.
*/
- kfree(vma->vm_private_data);
+ vma->vm_flags &= ~VM_FOREIGN;
+ kfree(foreign_map);
/* THIS IS VERY UNPLEASANT: do_mmap_pgoff() will set the vma->vm_file
* to NULL on failure. However, we need this in gntdev_clear_pte() to
@@ -780,9 +780,8 @@ static pte_t gntdev_clear_pte(struct vm_
/* "Destructor" for a VM area.
*/
static void gntdev_vma_close(struct vm_area_struct *vma) {
- if (vma->vm_private_data) {
+ if (vma->vm_flags & VM_FOREIGN)
kfree(vma->vm_private_data);
- }
}
/* Called when an ioctl is made on the device.
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