Add Posix(through rollback) support in sys_mlock/sys_munlock/sys_mlockall
/sys_munlockall.
Signed-off-by: Shaoping Wang <[email protected]>
--
mlock.c | 279 +++++++++++++++++++++++++++++++++++++++++++---------------------
1 files changed, 189 insertions(+), 90 deletions(-)
diff -urN linux-2.6.15.orig/mm/mlock.c linux-2.6.15/mm/mlock.c
--- linux-2.6.15.orig/mm/mlock.c 2006-01-02 22:21:10.000000000 -0500
+++ linux-2.6.15/mm/mlock.c 2006-03-07 10:50:52.000000000 -0500
@@ -3,6 +3,7 @@
*
* (C) Copyright 1995 Linus Torvalds
* (C) Copyright 2002 Christoph Hellwig
+ * (C) Copyright 2006 Shaoping Wang
*/
#include <linux/mman.h>
@@ -10,72 +11,119 @@
#include <linux/mempolicy.h>
#include <linux/syscalls.h>
-
-static int mlock_fixup(struct vm_area_struct *vma, struct
vm_area_struct **prev,
- unsigned long start, unsigned long end, unsigned int newflags)
+static int do_mlock(unsigned long start, size_t len,unsigned int jump_hole)
{
- struct mm_struct * mm = vma->vm_mm;
- pgoff_t pgoff;
- int pages;
- int ret = 0;
+ unsigned long end=0,vmoff=0;
+ unsigned long pages=0;
+ struct mm_struct *mm=current->mm;
+ struct vm_area_struct * vma, *prev, **pprev,*next;
+ int ret=0;
- if (newflags == vma->vm_flags) {
- *prev = vma;
- goto out;
- }
+ len = PAGE_ALIGN(len);
+ end = start + len;
+ if (end < start)
+ return -EINVAL;
+ if (end == start)
+ return 0;
- pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
- *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
- vma->vm_file, pgoff, vma_policy(vma));
- if (*prev) {
- vma = *prev;
- goto success;
+ vma = find_vma_prev(current->mm, start, &prev);
+ if (!vma || vma->vm_start > start)
+ return -ENOMEM;
+ else if (vma->vm_start < start){
+ prev=vma;
+ ret = split_vma(mm, prev, start, 0);
+ if(!ret)
+ vma=prev->vm_next;
+ else {
+ return ret;
+ }
}
- *prev = vma;
-
- if (start != vma->vm_start) {
- ret = split_vma(mm, vma, start, 1);
- if (ret)
+ while(vma->vm_start < end){
+ vmoff =vma->vm_end; /* Record where we have proceeded. */
+ if (vma->vm_end > end){
+ ret = split_vma(mm, vma, end, 0);
+ if (ret)
+ goto out;
+ }
+ if(vma->vm_flags & VM_LOCKED)
+ goto next;
+ vma->vm_flags |= VM_LOCKED;
+ vma->vm_wire_change =1;
+ pages += (vma->vm_end-vma->vm_start) >> PAGE_SHIFT;
+
+ if (!(vma->vm_flags & VM_IO)) {
+ ret = make_pages_wired(vma->vm_start, vma->vm_end);
+ if(ret<0){
+ vma->vm_flags &= ~VM_LOCKED;
+ vma->vm_wire_change =0;
+ goto out;
+ }
+ }
+next:
+ if(vma->vm_end ==end)
+ break;
+ prev =vma;
+ vma =vma->vm_next;
+
+ /* If called from do_mlockall,
+ * we may jump over holes.
+ */
+ if(jump_hole){
+ if(vma)
+ continue;
+ else
+ goto out;
+ }
+ else if (!vma || vma->vm_start != prev->vm_end){
+ ret = -ENOMEM;
goto out;
+ }
}
- if (end != vma->vm_end) {
- ret = split_vma(mm, vma, end, 0);
- if (ret)
- goto out;
- }
+out:
+ pprev =&prev;
+ vma = find_vma_prev(mm, start, pprev);
-success:
- /*
- * vm_flags is protected by the mmap_sem held in write mode.
- * It's okay if try_to_unmap_one unmaps a page just after we
- * set VM_LOCKED, make_pages_present below will bring it back.
- */
- vma->vm_flags = newflags;
-
- /*
- * Keep track of amount of locked VM.
- */
- pages = (end - start) >> PAGE_SHIFT;
- if (newflags & VM_LOCKED) {
- pages = -pages;
- if (!(newflags & VM_IO))
- ret = make_pages_present(start, end);
+ /* If error happened,do rollback.
+ * Whether success or not,try to merge the vmas.
+ */
+ while( vma && vma->vm_end <= vmoff ){
+ if(vma->vm_wire_change) {
+ if(ret){
+ make_pages_unwired(mm, vma->vm_start, vma->vm_end);
+ vma->vm_flags &= ~VM_LOCKED;
+ }
+ vma->vm_wire_change =0;
+ }
+ next=vma->vm_next;
+ if(next && next->vm_wire_change) {
+ if(ret){
+ make_pages_unwired(mm, next->vm_start, next->vm_end);
+ next->vm_flags &= ~VM_LOCKED;
+ }
+ next->vm_wire_change=0;
+ }
+ *pprev=vma_merge(mm, *pprev, vma->vm_start, vma->vm_end, vma->vm_flags,
+ vma->anon_vma,vma->vm_file, vma->vm_pgoff, vma_policy(vma));
+ if(*pprev)
+ vma =*pprev;
+ vma =vma->vm_next;
}
- vma->vm_mm->locked_vm -= pages;
-out:
- if (ret == -ENOMEM)
- ret = -EAGAIN;
+ if(!ret)
+ mm->locked_vm += pages;
return ret;
}
-static int do_mlock(unsigned long start, size_t len, int on)
+
+static int do_munlock(unsigned long start, size_t len, unsigned int jump_hole)
{
- unsigned long nstart, end, tmp;
- struct vm_area_struct * vma, * prev;
- int error;
+ unsigned long end=0,vmoff=0;
+ unsigned long pages=0;
+ struct mm_struct *mm=current->mm;
+ struct vm_area_struct * vma, *prev, **pprev, *next;
+ int ret=0;
len = PAGE_ALIGN(len);
end = start + len;
@@ -86,38 +134,81 @@
vma = find_vma_prev(current->mm, start, &prev);
if (!vma || vma->vm_start > start)
return -ENOMEM;
+ else if (vma->vm_start < start){
+ prev=vma;
+ ret = split_vma(mm, prev, start, 0);
+ if(!ret)
+ vma=prev->vm_next;
+ else
+ return ret;
+ }
- if (start > vma->vm_start)
- prev = vma;
+ while(vma->vm_start < end){
+ vmoff =vma->vm_end;
+ if (vma->vm_end > end){
+ ret = split_vma(mm, vma, end, 0);
+ if (ret)
+ goto out;
+ }
- for (nstart = start ; ; ) {
- unsigned int newflags;
+ if(!(vma->vm_flags & VM_LOCKED))
+ goto next;
- /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
+ vma->vm_wire_change=1;
+ pages += (vma->vm_end -vma->vm_start) >>PAGE_SHIFT;
- newflags = vma->vm_flags | VM_LOCKED;
- if (!on)
- newflags &= ~VM_LOCKED;
-
- tmp = vma->vm_end;
- if (tmp > end)
- tmp = end;
- error = mlock_fixup(vma, &prev, nstart, tmp, newflags);
- if (error)
- break;
- nstart = tmp;
- if (nstart < prev->vm_end)
- nstart = prev->vm_end;
- if (nstart >= end)
+next:
+ if(vma->vm_end ==end)
break;
+ prev =vma;
+ vma =vma->vm_next;
- vma = prev->vm_next;
- if (!vma || vma->vm_start != nstart) {
- error = -ENOMEM;
- break;
+ /* If called from munlockall,
+ * we may jump over holes.
+ */
+ if(jump_hole){
+ if(!vma)
+ goto out;
+ else
+ continue;
+ }
+ else if (!vma || (vma->vm_start != prev->vm_end) ){
+ ret= -ENOMEM;
+ goto out;
}
}
- return error;
+
+out:
+ pprev =&prev;
+ vma = find_vma_prev(current->mm, start, pprev);
+
+ while( vma && vma->vm_end <= vmoff ){
+ if(!ret && vma->vm_wire_change){
+ if (!(vma->vm_flags & VM_IO))
+ make_pages_unwired(mm, vma->vm_start, vma->vm_end);
+ vma->vm_flags &=~VM_LOCKED;
+ }
+ vma->vm_wire_change =0;
+ next = vma->vm_next;
+ if(next){
+ if(!ret && next->vm_wire_change){
+ if (!(next->vm_flags & VM_IO))
+ make_pages_unwired(mm, next->vm_start,next->vm_end);
+ next->vm_flags &=~VM_LOCKED;
+ }
+ next->vm_wire_change =0;
+ }
+ *pprev =vma_merge(mm, *pprev, vma->vm_start, vma->vm_end, vma->vm_flags,
+ vma->anon_vma,vma->vm_file, vma->vm_pgoff, vma_policy(vma));
+ if(*pprev)
+ vma =*pprev;
+ vma =vma->vm_next;
+ }
+
+ if(!ret)
+ mm->locked_vm -= pages;
+
+ return ret;
}
asmlinkage long sys_mlock(unsigned long start, size_t len)
@@ -141,7 +232,7 @@
/* check against resource limits */
if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
- error = do_mlock(start, len, 1);
+ error = do_mlock(start, len, 0);
up_write(¤t->mm->mmap_sem);
return error;
}
@@ -153,33 +244,41 @@
down_write(¤t->mm->mmap_sem);
len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
start &= PAGE_MASK;
- ret = do_mlock(start, len, 0);
+ ret = do_munlock(start, len,0);
up_write(¤t->mm->mmap_sem);
return ret;
}
static int do_mlockall(int flags)
{
- struct vm_area_struct * vma, * prev = NULL;
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct * vma;
unsigned int def_flags = 0;
+ unsigned long start;
+ int ret = 0;
if (flags & MCL_FUTURE)
def_flags = VM_LOCKED;
- current->mm->def_flags = def_flags;
+ mm->def_flags = def_flags;
if (flags == MCL_FUTURE)
goto out;
+ vma=mm->mmap;
+ start = vma->vm_start;
+ ret=do_mlock(start,TASK_SIZE,1);
+out:
+ return ret;
+}
- for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
- unsigned int newflags;
-
- newflags = vma->vm_flags | VM_LOCKED;
- if (!(flags & MCL_CURRENT))
- newflags &= ~VM_LOCKED;
+static int do_munlockall(void)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct * vma;
+ unsigned long start;
+
+ vma=mm->mmap;
+ start = vma->vm_start;
+ do_munlock(start,TASK_SIZE,1);
- /* Ignore errors */
- mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
- }
-out:
return 0;
}
@@ -214,7 +313,7 @@
int ret;
down_write(¤t->mm->mmap_sem);
- ret = do_mlockall(0);
+ ret = do_munlockall();
up_write(¤t->mm->mmap_sem);
return ret;
}
-
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