As usual, written and (build-)tested on 2.6.27.4 and made apply to the 2.6.18
tree without further testing.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Index: head-2008-11-04/drivers/xen/blktap/blktap.c
===================================================================
--- head-2008-11-04.orig/drivers/xen/blktap/blktap.c 2008-10-01
16:35:04.000000000 +0200
+++ head-2008-11-04/drivers/xen/blktap/blktap.c 2008-11-05 14:27:58.000000000
+0100
@@ -611,9 +611,13 @@ static int blktap_release(struct inode *
/* Clear any active mappings and free foreign map table */
if (info->vma) {
+ struct mm_struct *mm = info->vma->vm_mm;
+
+ down_write(&mm->mmap_sem);
zap_page_range(
info->vma, info->vma->vm_start,
info->vma->vm_end - info->vma->vm_start, NULL);
+ up_write(&mm->mmap_sem);
kfree(info->vma->vm_private_data);
@@ -993,12 +997,13 @@ static void fast_flush_area(pending_req_
int tapidx)
{
struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST*2];
- unsigned int i, invcount = 0;
+ unsigned int i, invcount = 0, locked = 0;
struct grant_handle_pair *khandle;
uint64_t ptep;
int ret, mmap_idx;
unsigned long kvaddr, uvaddr;
tap_blkif_t *info;
+ struct mm_struct *mm;
info = tapfds[tapidx];
@@ -1008,13 +1013,15 @@ static void fast_flush_area(pending_req_
return;
}
+ mm = info->vma ? info->vma->vm_mm : NULL;
+
if (info->vma != NULL &&
xen_feature(XENFEAT_auto_translated_physmap)) {
- down_write(&info->vma->vm_mm->mmap_sem);
+ down_write(&mm->mmap_sem);
zap_page_range(info->vma,
MMAP_VADDR(info->user_vstart, u_idx, 0),
req->nr_pages << PAGE_SHIFT, NULL);
- up_write(&info->vma->vm_mm->mmap_sem);
+ up_write(&mm->mmap_sem);
return;
}
@@ -1039,10 +1046,13 @@ static void fast_flush_area(pending_req_
if (khandle->user != INVALID_GRANT_HANDLE) {
BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
+ if (!locked++)
+ down_write(&mm->mmap_sem);
if (create_lookup_pte_addr(
- info->vma->vm_mm,
+ mm,
MMAP_VADDR(info->user_vstart, u_idx, i),
&ptep) !=0) {
+ up_write(&mm->mmap_sem);
WPRINTK("Couldn't get a pte addr!\n");
return;
}
@@ -1061,10 +1071,17 @@ static void fast_flush_area(pending_req_
GNTTABOP_unmap_grant_ref, unmap, invcount);
BUG_ON(ret);
- if (info->vma != NULL && !xen_feature(XENFEAT_auto_translated_physmap))
+ if (info->vma != NULL &&
+ !xen_feature(XENFEAT_auto_translated_physmap)) {
+ if (!locked++)
+ down_write(&mm->mmap_sem);
zap_page_range(info->vma,
MMAP_VADDR(info->user_vstart, u_idx, 0),
req->nr_pages << PAGE_SHIFT, NULL);
+ }
+
+ if (locked)
+ up_write(&mm->mmap_sem);
}
/******************************************************************
@@ -1356,6 +1373,7 @@ static void dispatch_rw_block_io(blkif_t
int pending_idx = RTN_PEND_IDX(pending_req,pending_req->mem_idx);
int usr_idx;
uint16_t mmap_idx = pending_req->mem_idx;
+ struct mm_struct *mm;
if (blkif->dev_num < 0 || blkif->dev_num > MAX_TAP_DEV)
goto fail_response;
@@ -1416,6 +1434,9 @@ static void dispatch_rw_block_io(blkif_t
pending_req->status = BLKIF_RSP_OKAY;
pending_req->nr_pages = nseg;
op = 0;
+ mm = info->vma->vm_mm;
+ if (!xen_feature(XENFEAT_auto_translated_physmap))
+ down_write(&mm->mmap_sem);
for (i = 0; i < nseg; i++) {
unsigned long uvaddr;
unsigned long kvaddr;
@@ -1434,9 +1455,9 @@ static void dispatch_rw_block_io(blkif_t
if (!xen_feature(XENFEAT_auto_translated_physmap)) {
/* Now map it to user. */
- ret = create_lookup_pte_addr(info->vma->vm_mm,
- uvaddr, &ptep);
+ ret = create_lookup_pte_addr(mm, uvaddr, &ptep);
if (ret) {
+ up_write(&mm->mmap_sem);
WPRINTK("Couldn't get a pte addr!\n");
goto fail_flush;
}
@@ -1458,6 +1479,8 @@ static void dispatch_rw_block_io(blkif_t
BUG_ON(ret);
if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ up_write(&mm->mmap_sem);
+
for (i = 0; i < (nseg*2); i+=2) {
unsigned long uvaddr;
unsigned long kvaddr;
@@ -1531,7 +1554,7 @@ static void dispatch_rw_block_io(blkif_t
goto fail_flush;
if (xen_feature(XENFEAT_auto_translated_physmap))
- down_write(&info->vma->vm_mm->mmap_sem);
+ down_write(&mm->mmap_sem);
/* Mark mapped pages as reserved: */
for (i = 0; i < req->nr_segments; i++) {
unsigned long kvaddr;
@@ -1545,13 +1568,13 @@ static void dispatch_rw_block_io(blkif_t
MMAP_VADDR(info->user_vstart,
usr_idx, i), pg);
if (ret) {
- up_write(&info->vma->vm_mm->mmap_sem);
+ up_write(&mm->mmap_sem);
goto fail_flush;
}
}
}
if (xen_feature(XENFEAT_auto_translated_physmap))
- up_write(&info->vma->vm_mm->mmap_sem);
+ up_write(&mm->mmap_sem);
/*record [mmap_idx,pending_idx] to [usr_idx] mapping*/
info->idx_map[usr_idx] = MAKE_ID(mmap_idx, pending_idx);
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