From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Peter Xu <peterx@redhat.com>, Martin Cracauer <cracauer@cons.org>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Hugh Dickins <hughd@google.com>,
Jerome Glisse <jglisse@redhat.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Matthew Wilcox <willy@infradead.org>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Brian Geffon <bgeffon@google.com>,
Maya Gokhale <gokhale2@llnl.gov>,
Denis Plotnikov <dplotnikov@virtuozzo.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Marty McFadden <mcfadden8@llnl.gov>,
David Hildenbrand <david@redhat.com>,
Bobby Powers <bobbypowers@gmail.com>,
Mel Gorman <mgorman@suse.de>
Subject: [PATCH RESEND v6 16/16] mm/userfaultfd: Honor FAULT_FLAG_KILLABLE in fault path
Date: Thu, 20 Feb 2020 11:03:00 -0500 [thread overview]
Message-ID: <20200220160300.9941-1-peterx@redhat.com> (raw)
In-Reply-To: <20200220155353.8676-1-peterx@redhat.com>
Userfaultfd fault path was by default killable even if the caller does
not have FAULT_FLAG_KILLABLE. That makes sense before in that when
with gup we don't have FAULT_FLAG_KILLABLE properly set before. Now
after previous patch we've got FAULT_FLAG_KILLABLE applied even for
gup code so it should also make sense to let userfaultfd to honor the
FAULT_FLAG_KILLABLE.
Because we're unconditionally setting FAULT_FLAG_KILLABLE in gup code
right now, this patch should have no functional change. It also
cleaned the code a little bit by introducing some helpers.
Signed-off-by: Peter Xu <peterx@redhat.com>
---
fs/userfaultfd.c | 36 ++++++++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 8 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index c076d3295958..703c1c3faa6e 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -334,6 +334,30 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx,
return ret;
}
+/* Should pair with userfaultfd_signal_pending() */
+static inline long userfaultfd_get_blocking_state(unsigned int flags)
+{
+ if (flags & FAULT_FLAG_INTERRUPTIBLE)
+ return TASK_INTERRUPTIBLE;
+
+ if (flags & FAULT_FLAG_KILLABLE)
+ return TASK_KILLABLE;
+
+ return TASK_UNINTERRUPTIBLE;
+}
+
+/* Should pair with userfaultfd_get_blocking_state() */
+static inline bool userfaultfd_signal_pending(unsigned int flags)
+{
+ if (flags & FAULT_FLAG_INTERRUPTIBLE)
+ return signal_pending(current);
+
+ if (flags & FAULT_FLAG_KILLABLE)
+ return fatal_signal_pending(current);
+
+ return false;
+}
+
/*
* The locking rules involved in returning VM_FAULT_RETRY depending on
* FAULT_FLAG_ALLOW_RETRY, FAULT_FLAG_RETRY_NOWAIT and
@@ -355,7 +379,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
struct userfaultfd_ctx *ctx;
struct userfaultfd_wait_queue uwq;
vm_fault_t ret = VM_FAULT_SIGBUS;
- bool must_wait, return_to_userland;
+ bool must_wait;
long blocking_state;
/*
@@ -462,9 +486,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
uwq.ctx = ctx;
uwq.waken = false;
- return_to_userland = vmf->flags & FAULT_FLAG_INTERRUPTIBLE;
- blocking_state = return_to_userland ? TASK_INTERRUPTIBLE :
- TASK_KILLABLE;
+ blocking_state = userfaultfd_get_blocking_state(vmf->flags);
spin_lock_irq(&ctx->fault_pending_wqh.lock);
/*
@@ -490,8 +512,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
up_read(&mm->mmap_sem);
if (likely(must_wait && !READ_ONCE(ctx->released) &&
- (return_to_userland ? !signal_pending(current) :
- !fatal_signal_pending(current)))) {
+ !userfaultfd_signal_pending(vmf->flags))) {
wake_up_poll(&ctx->fd_wqh, EPOLLIN);
schedule();
ret |= VM_FAULT_MAJOR;
@@ -513,8 +534,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
set_current_state(blocking_state);
if (READ_ONCE(uwq.waken) ||
READ_ONCE(ctx->released) ||
- (return_to_userland ? signal_pending(current) :
- fatal_signal_pending(current)))
+ userfaultfd_signal_pending(vmf->flags))
break;
schedule();
}
--
2.24.1
next prev parent reply other threads:[~2020-02-20 16:03 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 15:53 [PATCH RESEND v6 00/16] mm: Page fault enhancements Peter Xu
2020-02-20 15:53 ` [PATCH RESEND v6 01/16] mm/gup: Rename "nonblocking" to "locked" where proper Peter Xu
2020-02-20 15:53 ` [PATCH RESEND v6 02/16] mm/gup: Fix __get_user_pages() on fault retry of hugetlb Peter Xu
2020-03-02 19:02 ` David Hildenbrand
2020-03-02 20:07 ` Peter Xu
2020-03-02 20:22 ` David Hildenbrand
2020-02-20 15:53 ` [PATCH RESEND v6 03/16] mm: Introduce fault_signal_pending() Peter Xu
2020-03-02 19:04 ` David Hildenbrand
2020-02-20 15:53 ` [PATCH RESEND v6 04/16] x86/mm: Use helper fault_signal_pending() Peter Xu
2020-02-20 15:58 ` [PATCH RESEND v6 05/16] arc/mm: " Peter Xu
2020-02-20 15:59 ` [PATCH RESEND v6 06/16] arm64/mm: " Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 07/16] powerpc/mm: " Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 08/16] sh/mm: " Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 09/16] mm: Return faster for non-fatal signals in user mode faults Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 10/16] userfaultfd: Don't retake mmap_sem to emulate NOPAGE Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 11/16] mm: Introduce FAULT_FLAG_DEFAULT Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 13/16] mm: Allow VM_FAULT_RETRY for multiple times Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 15/16] mm/gup: Allow to react to fatal signals Peter Xu
2020-02-20 16:03 ` Peter Xu [this message]
2020-02-20 19:53 ` [PATCH RESEND v6 12/16] mm: Introduce FAULT_FLAG_INTERRUPTIBLE Peter Xu
2020-02-20 19:53 ` [PATCH RESEND v6 14/16] mm/gup: Allow VM_FAULT_RETRY for multiple times Peter Xu
2020-02-21 19:26 ` [PATCH RESEND v6 00/16] mm: Page fault enhancements Brian Geffon
2020-03-02 17:31 ` Peter Xu
2020-02-21 19:32 ` Linus Torvalds
2020-02-21 20:11 ` Peter Xu
2020-03-07 20:33 ` David Hildenbrand
2020-03-07 21:47 ` Peter Xu
2020-03-08 12:12 ` David Hildenbrand
2020-03-09 19:51 ` Peter Xu
2020-03-09 20:06 ` David Hildenbrand
2020-03-08 12:49 ` David Hildenbrand
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