All of lore.kernel.org
 help / color / mirror / Atom feed
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 v2 06/10] mmap locking API: convert nested write lock sites
Date: Thu, 26 Mar 2020 19:10:54 -0700	[thread overview]
Message-ID: <20200327021058.221911-7-walken@google.com> (raw)
In-Reply-To: <20200327021058.221911-1-walken@google.com>

Add API for nested write locks and convert the few call sites doing that.

Signed-off-by: Michel Lespinasse <walken@google.com>
---
 arch/um/include/asm/mmu_context.h |  5 +++--
 include/linux/mmap_lock.h         | 11 +++++++++++
 kernel/fork.c                     |  4 ++--
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h
index 62262c5c7785..cc15173f7518 100644
--- a/arch/um/include/asm/mmu_context.h
+++ b/arch/um/include/asm/mmu_context.h
@@ -8,6 +8,7 @@
 
 #include <linux/sched.h>
 #include <linux/mm_types.h>
+#include <linux/mmap_lock.h>
 
 #include <asm/mmu.h>
 
@@ -47,9 +48,9 @@ static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
 	 * when the new ->mm is used for the first time.
 	 */
 	__switch_mm(&new->context.id);
-	down_write_nested(&new->mmap_sem, 1);
+	mmap_write_lock_nested(new, 1);
 	uml_setup_stubs(new);
-	mmap_write_unlock(new);
+	mmap_write_unlock_nested(new);
 }
 
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, 
diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h
index cffd25afe92b..40a972a26857 100644
--- a/include/linux/mmap_lock.h
+++ b/include/linux/mmap_lock.h
@@ -11,6 +11,11 @@ static inline void mmap_write_lock(struct mm_struct *mm)
 	down_write(&mm->mmap_sem);
 }
 
+static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass)
+{
+	down_write_nested(&mm->mmap_sem, subclass);
+}
+
 static inline int mmap_write_lock_killable(struct mm_struct *mm)
 {
 	return down_write_killable(&mm->mmap_sem);
@@ -26,6 +31,12 @@ static inline void mmap_write_unlock(struct mm_struct *mm)
 	up_write(&mm->mmap_sem);
 }
 
+/* Pairs with mmap_write_lock_nested() */
+static inline void mmap_write_unlock_nested(struct mm_struct *mm)
+{
+	up_write(&mm->mmap_sem);
+}
+
 static inline void mmap_downgrade_write_lock(struct mm_struct *mm)
 {
 	downgrade_write(&mm->mmap_sem);
diff --git a/kernel/fork.c b/kernel/fork.c
index c321910d46e8..3460308b2213 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -497,7 +497,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
 	/*
 	 * Not linked in yet - no deadlock potential:
 	 */
-	down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING);
+	mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING);
 
 	/* No ordering required: file already has been exposed. */
 	RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm));
@@ -612,7 +612,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
 	/* a new mm has just been created */
 	retval = arch_dup_mmap(oldmm, mm);
 out:
-	mmap_write_unlock(mm);
+	mmap_write_unlock_nested(mm);
 	flush_tlb_mm(oldmm);
 	mmap_write_unlock(oldmm);
 	dup_userfaultfd_complete(&uf);
-- 
2.26.0.rc2.310.g2932bb562d-goog


  parent reply	other threads:[~2020-03-27  2:11 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-27  2:10 [PATCH v2 00/10] Add a new mmap locking API wrapping mmap_sem calls Michel Lespinasse
2020-03-27  2:10 ` Michel Lespinasse
2020-03-27  2:10 ` [PATCH v2 01/10] mmap locking API: initial implementation as rwsem wrappers Michel Lespinasse
2020-03-27  2:10   ` Michel Lespinasse
2020-03-27 12:16   ` Jason Gunthorpe
2020-03-27 21:52     ` Michel Lespinasse
2020-03-27 21:52       ` Michel Lespinasse
2020-03-27  2:10 ` [PATCH v2 02/10] MMU notifier: use the new mmap locking API Michel Lespinasse
2020-03-27  2:10   ` Michel Lespinasse
2020-03-27  2:10 ` [PATCH v2 03/10] DMA reservations: " Michel Lespinasse
2020-03-27  2:10   ` Michel Lespinasse
2020-03-27  2:10 ` [PATCH v2 04/10] mmap locking API: use coccinelle to convert mmap_sem rwsem call sites Michel Lespinasse
2020-03-27  2:10   ` Michel Lespinasse
2020-03-27  7:22   ` Markus Elfring
2020-03-27  7:22     ` [Cocci] " Markus Elfring
2020-03-27  7:44     ` Michel Lespinasse
2020-03-27  7:44       ` [Cocci] " Michel Lespinasse
2020-03-27  7:44       ` Michel Lespinasse
2020-03-27  8:00       ` [v2 " Markus Elfring
2020-03-27  8:00         ` [Cocci] " Markus Elfring
2020-03-27  8:08         ` Michel Lespinasse
2020-03-27  8:08           ` [Cocci] " Michel Lespinasse
2020-03-27  8:08           ` Michel Lespinasse
2020-03-27  2:10 ` [PATCH v2 05/10] mmap locking API: convert mmap_sem call sites missed by coccinelle Michel Lespinasse
2020-03-27  2:10   ` Michel Lespinasse
2020-03-27  8:21   ` Markus Elfring
2020-03-27  8:21     ` [Cocci] " Markus Elfring
2020-03-27  2:10 ` Michel Lespinasse [this message]
2020-03-27  2:10   ` [PATCH v2 06/10] mmap locking API: convert nested write lock sites Michel Lespinasse
2020-03-27  2:10 ` [PATCH v2 07/10] mmap locking API: add mmap_read_release() and mmap_read_unlock_non_owner() Michel Lespinasse
2020-03-27  2:10   ` Michel Lespinasse
2020-03-27  4:46   ` Davidlohr Bueso
2020-03-27  5:09     ` Michel Lespinasse
2020-03-27  5:09       ` Michel Lespinasse
2020-03-27  2:10 ` [PATCH v2 08/10] mmap locking API: add MMAP_LOCK_INITIALIZER Michel Lespinasse
2020-03-27  2:10   ` Michel Lespinasse
2020-03-27  2:10 ` [PATCH v2 09/10] mmap locking API: use lockdep_assert_held Michel Lespinasse
2020-03-27  2:10   ` Michel Lespinasse
2020-03-27  4:48   ` Davidlohr Bueso
2020-03-27  2:10 ` [PATCH v2 10/10] mmap locking API: rename mmap_sem to mmap_lock Michel Lespinasse
2020-03-27  2:10   ` Michel Lespinasse

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200327021058.221911-7-walken@google.com \
    --to=walken@google.com \
    --cc=Liam.Howlett@oracle.com \
    --cc=Markus.Elfring@web.de \
    --cc=akpm@linux-foundation.org \
    --cc=dave@stgolabs.net \
    --cc=hughd@google.com \
    --cc=jgg@ziepe.ca \
    --cc=jglisse@redhat.com \
    --cc=ldufour@linux.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=peterz@infradead.org \
    --cc=rientjes@google.com \
    --cc=vbabka@suse.cz \
    --cc=willy@infradead.org \
    --cc=yinghan@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.