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xen/gntdev: remove erronous use of copy_to_user 

Since there is now a mapping of granted pages in kernel address space in
both PV and HVM, use it for UNMAP_NOTIFY_CLEAR_BYTE instead of accessing
memory via copy_to_user and triggering sleep-in-atomic warnings.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Daniel De Graaf 2013-01-02 17:57:13 -05:00 committed by Konrad Rzeszutek Wilk
parent 16a1d0225e
commit 1affa98d23
1 changed files with 3 additions and 10 deletions
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13
drivers/xen/gntdev.c
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@ -312,17 +312,10 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
int pgno = (map->notify.addr >> PAGE_SHIFT); int pgno = (map->notify.addr >> PAGE_SHIFT);
if (pgno >= offset && pgno < offset + pages && use_ptemod) { if (pgno >= offset && pgno < offset + pages) {
void __user *tmp = (void __user *) /* No need for kmap, pages are in lowmem */
map->vma->vm_start + map->notify.addr; uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
err = copy_to_user(tmp, &err, 1);
if (err)
return -EFAULT;
map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
} else if (pgno >= offset && pgno < offset + pages) {
uint8_t *tmp = kmap(map->pages[pgno]);
tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
kunmap(map->pages[pgno]);
map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
} }
} }