From: Michel Lespinasse <walken@google.com>
To: Andrew Morton <akpm@linux-foundation.org>, linux-mm <linux-mm@kvack.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Laurent Dufour <ldufour@linux.ibm.com>,
Vlastimil Babka <vbabka@suse.cz>,
Matthew Wilcox <willy@infradead.org>,
Liam Howlett <Liam.Howlett@oracle.com>,
Jerome Glisse <jglisse@redhat.com>,
Davidlohr Bueso <dave@stgolabs.net>,
David Rientjes <rientjes@google.com>,
Hugh Dickins <hughd@google.com>, Ying Han <yinghan@google.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Markus Elfring <Markus.Elfring@web.de>,
Michel Lespinasse <walken@google.com>
Subject: [PATCH v3 07/10] mmap locking API: add mmap_read_release() and mmap_read_unlock_non_owner()
Date: Fri, 27 Mar 2020 15:50:59 -0700 [thread overview]
Message-ID: <20200327225102.25061-8-walken@google.com> (raw)
In-Reply-To: <20200327225102.25061-1-walken@google.com>
Add a couple APIs to allow splitting mmap_read_unlock() into two calls:
- mmap_read_release(), called by the task that had taken the mmap lock;
- mmap_read_unlock_non_owner(), called from a work queue.
These apis are used by kernel/bpf/stackmap.c only.
Signed-off-by: Michel Lespinasse <walken@google.com>
---
include/linux/mmap_lock.h | 10 ++++++++++
kernel/bpf/stackmap.c | 9 ++++-----
2 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h
index 36fb758401d6..a80cf9695514 100644
--- a/include/linux/mmap_lock.h
+++ b/include/linux/mmap_lock.h
@@ -62,4 +62,14 @@ static inline void mmap_read_unlock(struct mm_struct *mm)
up_read(&mm->mmap_sem);
}
+static inline void mmap_read_release(struct mm_struct *mm, unsigned long ip)
+{
+ rwsem_release(&mm->mmap_sem.dep_map, ip);
+}
+
+static inline void mmap_read_unlock_non_owner(struct mm_struct *mm)
+{
+ up_read_non_owner(&mm->mmap_sem);
+}
+
#endif /* _LINUX_MMAP_LOCK_H */
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index f2115f691577..413b512a99eb 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -33,7 +33,7 @@ struct bpf_stack_map {
/* irq_work to run up_read() for build_id lookup in nmi context */
struct stack_map_irq_work {
struct irq_work irq_work;
- struct rw_semaphore *sem;
+ struct mm_struct *mm;
};
static void do_up_read(struct irq_work *entry)
@@ -41,8 +41,7 @@ static void do_up_read(struct irq_work *entry)
struct stack_map_irq_work *work;
work = container_of(entry, struct stack_map_irq_work, irq_work);
- up_read_non_owner(work->sem);
- work->sem = NULL;
+ mmap_read_unlock_non_owner(work->mm);
}
static DEFINE_PER_CPU(struct stack_map_irq_work, up_read_work);
@@ -332,14 +331,14 @@ static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
if (!work) {
mmap_read_unlock(current->mm);
} else {
- work->sem = ¤t->mm->mmap_sem;
+ work->mm = current->mm;
irq_work_queue(&work->irq_work);
/*
* The irq_work will release the mmap_sem with
* up_read_non_owner(). The rwsem_release() is called
* here to release the lock from lockdep's perspective.
*/
- rwsem_release(¤t->mm->mmap_sem.dep_map, _RET_IP_);
+ mmap_read_release(current->mm, _RET_IP_);
}
}
--
2.26.0.rc2.310.g2932bb562d-goog
next prev parent reply other threads:[~2020-03-27 22:51 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-27 22:50 [PATCH v3 00/10] Add a new mmap locking API wrapping mmap_sem calls Michel Lespinasse
2020-03-27 22:50 ` [PATCH v3 01/10] mmap locking API: initial implementation as rwsem wrappers Michel Lespinasse
2020-03-28 8:57 ` [PATCH v3 01/10] mmap locking API: initial implementation as rwsem wrappers (Michel Lespinasse) SeongJae Park
2020-03-27 22:50 ` [PATCH v3 02/10] MMU notifier: use the new mmap locking API Michel Lespinasse
2020-03-27 22:50 ` [PATCH v3 03/10] DMA reservations: " Michel Lespinasse
2020-03-27 22:50 ` [PATCH v3 04/10] mmap locking API: use coccinelle to convert mmap_sem rwsem call sites Michel Lespinasse
2020-03-27 22:50 ` [PATCH v3 05/10] mmap locking API: convert mmap_sem call sites missed by coccinelle Michel Lespinasse
2020-03-28 7:36 ` Markus Elfring
2020-03-28 7:47 ` Michel Lespinasse
2020-03-28 8:39 ` [v3 " Markus Elfring
2020-03-28 8:53 ` Michel Lespinasse
2020-03-28 9:01 ` Markus Elfring
2020-03-28 13:20 ` [v3 05/10] mmap locking API: Checking the Coccinelle software Markus Elfring
2020-03-28 13:42 ` [Cocci] " Julia Lawall
2020-03-28 13:52 ` Markus Elfring
2020-03-28 13:53 ` Julia Lawall
2020-03-28 14:00 ` Julia Lawall
2020-03-28 14:16 ` Markus Elfring
2020-03-30 6:10 ` [v3 05/10] mmap locking API: Improving " Markus Elfring
2020-03-30 8:47 ` [Cocci] " Julia Lawall
2020-03-30 10:15 ` Markus Elfring
2020-03-30 10:20 ` Julia Lawall
2020-03-30 10:42 ` Markus Elfring
2020-04-13 17:06 ` [PATCH v3 05/10] mmap locking API: convert mmap_sem call sites missed by coccinelle Daniel Jordan
2020-03-27 22:50 ` [PATCH v3 06/10] mmap locking API: convert nested write lock sites Michel Lespinasse
2020-04-01 13:42 ` Peter Zijlstra
2020-04-06 15:35 ` Michel Lespinasse
2020-04-06 15:58 ` Peter Zijlstra
2020-03-27 22:50 ` Michel Lespinasse [this message]
2020-04-01 13:46 ` [PATCH v3 07/10] mmap locking API: add mmap_read_release() and mmap_read_unlock_non_owner() Peter Zijlstra
2020-04-06 15:39 ` Michel Lespinasse
2020-03-27 22:51 ` [PATCH v3 08/10] mmap locking API: add MMAP_LOCK_INITIALIZER Michel Lespinasse
2020-03-27 22:51 ` [PATCH v3 09/10] mmap locking API: use lockdep_assert_held Michel Lespinasse
2020-03-27 22:51 ` [PATCH v3 10/10] mmap locking API: rename mmap_sem to mmap_lock Michel Lespinasse
2020-04-01 13:48 ` Peter Zijlstra
2020-04-06 15:49 ` Michel Lespinasse
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