mm: introduce fault_env
The idea borrowed from Peter's patch from patchset on speculative page
faults[1]:
Instead of passing around the endless list of function arguments,
replace the lot with a single structure so we can change context without
endless function signature changes.
The changes are mostly mechanical with exception of faultaround code:
filemap_map_pages() got reworked a bit.
This patch is preparation for the next one.
[1] http://lkml.kernel.org/r/20141020222841.302891540@infradead.org
Link: http://lkml.kernel.org/r/1466021202-61880-9-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 2d97952..85959d8 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -257,10 +257,9 @@
* fatal_signal_pending()s, and the mmap_sem must be released before
* returning it.
*/
-int handle_userfault(struct vm_area_struct *vma, unsigned long address,
- unsigned int flags, unsigned long reason)
+int handle_userfault(struct fault_env *fe, unsigned long reason)
{
- struct mm_struct *mm = vma->vm_mm;
+ struct mm_struct *mm = fe->vma->vm_mm;
struct userfaultfd_ctx *ctx;
struct userfaultfd_wait_queue uwq;
int ret;
@@ -269,7 +268,7 @@
BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
ret = VM_FAULT_SIGBUS;
- ctx = vma->vm_userfaultfd_ctx.ctx;
+ ctx = fe->vma->vm_userfaultfd_ctx.ctx;
if (!ctx)
goto out;
@@ -302,17 +301,17 @@
* without first stopping userland access to the memory. For
* VM_UFFD_MISSING userfaults this is enough for now.
*/
- if (unlikely(!(flags & FAULT_FLAG_ALLOW_RETRY))) {
+ if (unlikely(!(fe->flags & FAULT_FLAG_ALLOW_RETRY))) {
/*
* Validate the invariant that nowait must allow retry
* to be sure not to return SIGBUS erroneously on
* nowait invocations.
*/
- BUG_ON(flags & FAULT_FLAG_RETRY_NOWAIT);
+ BUG_ON(fe->flags & FAULT_FLAG_RETRY_NOWAIT);
#ifdef CONFIG_DEBUG_VM
if (printk_ratelimit()) {
printk(KERN_WARNING
- "FAULT_FLAG_ALLOW_RETRY missing %x\n", flags);
+ "FAULT_FLAG_ALLOW_RETRY missing %x\n", fe->flags);
dump_stack();
}
#endif
@@ -324,7 +323,7 @@
* and wait.
*/
ret = VM_FAULT_RETRY;
- if (flags & FAULT_FLAG_RETRY_NOWAIT)
+ if (fe->flags & FAULT_FLAG_RETRY_NOWAIT)
goto out;
/* take the reference before dropping the mmap_sem */
@@ -332,10 +331,11 @@
init_waitqueue_func_entry(&uwq.wq, userfaultfd_wake_function);
uwq.wq.private = current;
- uwq.msg = userfault_msg(address, flags, reason);
+ uwq.msg = userfault_msg(fe->address, fe->flags, reason);
uwq.ctx = ctx;
- return_to_userland = (flags & (FAULT_FLAG_USER|FAULT_FLAG_KILLABLE)) ==
+ return_to_userland =
+ (fe->flags & (FAULT_FLAG_USER|FAULT_FLAG_KILLABLE)) ==
(FAULT_FLAG_USER|FAULT_FLAG_KILLABLE);
spin_lock(&ctx->fault_pending_wqh.lock);
@@ -353,7 +353,7 @@
TASK_KILLABLE);
spin_unlock(&ctx->fault_pending_wqh.lock);
- must_wait = userfaultfd_must_wait(ctx, address, flags, reason);
+ must_wait = userfaultfd_must_wait(ctx, fe->address, fe->flags, reason);
up_read(&mm->mmap_sem);
if (likely(must_wait && !ACCESS_ONCE(ctx->released) &&