# HG changeset patch
# User Geoffrey Lefebvre <geoffrey@xxxxxxxxx>
# Date 1179788664 25200
# Node ID 236647990e986bca16f150c2fca87c0ed1ebd729
# Parent f5218394705702c1aaa02520be2ba5a9f2648f37
Added a hook for clearing ptes when a vma is freed by the kernel. Adapted from
gntdev.
diff -r f52183947057 -r 236647990e98
linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c
--- a/linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c Mon May 21 16:01:52
2007 -0700
+++ b/linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c Mon May 21 16:04:24
2007 -0700
@@ -269,6 +269,16 @@ static inline int GET_NEXT_REQ(unsigned
return INVALID_REQ;
}
+static inline int OFFSET_TO_USR_IDX(int offset)
+{
+ return offset / BLKIF_MAX_SEGMENTS_PER_REQUEST;
+}
+
+static inline int OFFSET_TO_SEG(int offset)
+{
+ return offset % BLKIF_MAX_SEGMENTS_PER_REQUEST;
+}
+
#define BLKTAP_INVALID_HANDLE(_g) \
(((_g->kernel) == INVALID_GRANT_HANDLE) && \
@@ -295,8 +305,94 @@ static struct page *blktap_nopage(struct
return NOPAGE_SIGBUS;
}
+static pte_t blktap_clear_pte(struct vm_area_struct *vma,
+ unsigned long uvaddr,
+ pte_t *ptep, int is_fullmm)
+{
+ pte_t copy = *ptep;
+ tap_blkif_t *info;
+ int offset, seg, usr_idx, pending_idx, mmap_idx;
+ unsigned long uvstart = vma->vm_start + (RING_PAGES << PAGE_SHIFT);
+ unsigned long kvaddr;
+ struct page **map;
+ struct page *pg;
+ struct grant_handle_pair *khandle;
+ struct gnttab_unmap_grant_ref unmap[2];
+ int count = 0;
+ static int print_warning = 1;
+
+ /*print a warning message once, if the hook gets called*/
+ if (print_warning) {
+ WPRINTK("Clear pte hook called!\n");
+ print_warning = 0;
+ }
+
+ /* If the address is before the start of the grant mapped region
+ * or if vm_file is NULL (meaning mmap failed and we have nothing to do)
+ */
+ if (uvaddr < uvstart || vma->vm_file == NULL)
+ return copy;
+
+ info = vma->vm_file->private_data;
+ map = vma->vm_private_data;
+
+ /* TODO Should these be changed to if statements? */
+ BUG_ON(!info);
+ BUG_ON(!info->idx_map);
+ BUG_ON(!map);
+
+ offset = (int) ((uvaddr - uvstart) >> PAGE_SHIFT);
+ usr_idx = OFFSET_TO_USR_IDX(offset);
+ seg = OFFSET_TO_SEG(offset);
+
+ pending_idx = MASK_PEND_IDX(ID_TO_IDX(info->idx_map[usr_idx]));
+ mmap_idx = ID_TO_MIDX(info->idx_map[usr_idx]);
+
+ kvaddr = idx_to_kaddr(mmap_idx, pending_idx, seg);
+ pg = pfn_to_page(__pa(kvaddr) >> PAGE_SHIFT);
+ ClearPageReserved(pg);
+ map[offset] = NULL;
+
+ khandle = &pending_handle(mmap_idx, pending_idx, seg);
+
+ if (khandle->kernel != INVALID_GRANT_HANDLE) {
+
+ gnttab_set_unmap_op(&unmap[count], kvaddr,
+ GNTMAP_host_map, khandle->kernel);
+ count++;
+
+ set_phys_to_machine(__pa(kvaddr) >> PAGE_SHIFT,
+ INVALID_P2M_ENTRY);
+ }
+
+ if (khandle->user != INVALID_GRANT_HANDLE) {
+
+ BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
+
+ gnttab_set_unmap_op(&unmap[count], virt_to_machine(ptep),
+ GNTMAP_host_map
+ | GNTMAP_application_map
+ | GNTMAP_contains_pte,
+ khandle->user);
+ count++;
+ }
+
+ if (count) {
+ int ret;
+
+ BLKTAP_INVALIDATE_HANDLE(khandle);
+
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
+ unmap, count);
+ BUG_ON(ret);
+ }
+
+ return copy;
+}
+
struct vm_operations_struct blktap_vm_ops = {
nopage: blktap_nopage,
+ zap_pte: blktap_clear_pte,
};
/******************************************************************
@@ -604,6 +700,10 @@ static int blktap_mmap(struct file *filp
vma->vm_private_data = map;
vma->vm_flags |= VM_FOREIGN;
vma->vm_flags |= VM_DONTCOPY;
+
+#ifdef CONFIG_X86
+ vma->vm_mm->context.has_foreign_mappings = 1;
+#endif
info->vma = vma;
info->ring_ok = 1;
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