From: Jason Gunthorpe <jgg@ziepe.ca>
To: linux-rdma@vger.kernel.org, linux-mm@kvack.org,
Jerome Glisse <jglisse@redhat.com>,
Ralph Campbell <rcampbell@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Subject: [RFC PATCH 02/11] mm/hmm: Use hmm_mirror not mm as an argument for hmm_register_range
Date: Thu, 23 May 2019 12:34:27 -0300 [thread overview]
Message-ID: <20190523153436.19102-3-jgg@ziepe.ca> (raw)
In-Reply-To: <20190523153436.19102-1-jgg@ziepe.ca>
From: Jason Gunthorpe <jgg@mellanox.com>
Ralph observes that hmm_register_range() can only be called by a driver
while a mirror is registered. Make this clear in the API by passing in the
mirror structure as a parameter.
This also simplifies understanding the lifetime model for struct hmm, as
the hmm pointer must be valid as part of a registered mirror so all we
need in hmm_register_range() is a simple kref_get.
Suggested-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
---
include/linux/hmm.h | 7 ++++---
mm/hmm.c | 14 +++++---------
2 files changed, 9 insertions(+), 12 deletions(-)
diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 8b91c90d3b88cb..87d29e085a69f7 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -503,7 +503,7 @@ static inline bool hmm_mirror_mm_is_alive(struct hmm_mirror *mirror)
* Please see Documentation/vm/hmm.rst for how to use the range API.
*/
int hmm_range_register(struct hmm_range *range,
- struct mm_struct *mm,
+ struct hmm_mirror *mirror,
unsigned long start,
unsigned long end,
unsigned page_shift);
@@ -539,7 +539,8 @@ static inline bool hmm_vma_range_done(struct hmm_range *range)
}
/* This is a temporary helper to avoid merge conflict between trees. */
-static inline int hmm_vma_fault(struct hmm_range *range, bool block)
+static inline int hmm_vma_fault(struct hmm_mirror *mirror,
+ struct hmm_range *range, bool block)
{
long ret;
@@ -552,7 +553,7 @@ static inline int hmm_vma_fault(struct hmm_range *range, bool block)
range->default_flags = 0;
range->pfn_flags_mask = -1UL;
- ret = hmm_range_register(range, range->vma->vm_mm,
+ ret = hmm_range_register(range, mirror,
range->start, range->end,
PAGE_SHIFT);
if (ret)
diff --git a/mm/hmm.c b/mm/hmm.c
index 824e7e160d8167..fa1b04fcfc2549 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -927,7 +927,7 @@ static void hmm_pfns_clear(struct hmm_range *range,
* Track updates to the CPU page table see include/linux/hmm.h
*/
int hmm_range_register(struct hmm_range *range,
- struct mm_struct *mm,
+ struct hmm_mirror *mirror,
unsigned long start,
unsigned long end,
unsigned page_shift)
@@ -935,7 +935,6 @@ int hmm_range_register(struct hmm_range *range,
unsigned long mask = ((1UL << page_shift) - 1UL);
range->valid = false;
- range->hmm = NULL;
if ((start & mask) || (end & mask))
return -EINVAL;
@@ -946,15 +945,12 @@ int hmm_range_register(struct hmm_range *range,
range->start = start;
range->end = end;
- range->hmm = hmm_get_or_create(mm);
- if (!range->hmm)
- return -EFAULT;
-
/* Check if hmm_mm_destroy() was call. */
- if (range->hmm->mm == NULL || range->hmm->dead) {
- hmm_put(range->hmm);
+ if (mirror->hmm->mm == NULL || mirror->hmm->dead)
return -EFAULT;
- }
+
+ range->hmm = mirror->hmm;
+ kref_get(&range->hmm->kref);
/* Initialize range to track CPU page table update */
mutex_lock(&range->hmm->lock);
--
2.21.0
next prev parent reply other threads:[~2019-05-23 15:34 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 15:34 [RFC PATCH 00/11] mm/hmm: Various revisions from a locking/code review Jason Gunthorpe
2019-05-23 15:34 ` [RFC PATCH 01/11] mm/hmm: Fix use after free with struct hmm in the mmu notifiers Jason Gunthorpe
2019-06-06 23:54 ` Ira Weiny
2019-06-07 14:17 ` Jason Gunthorpe
2019-05-23 15:34 ` Jason Gunthorpe [this message]
2019-05-23 18:22 ` [RFC PATCH 02/11] mm/hmm: Use hmm_mirror not mm as an argument for hmm_register_range Christoph Hellwig
2019-05-23 15:34 ` [RFC PATCH 03/11] mm/hmm: Hold a mmgrab from hmm to mm Jason Gunthorpe
2019-05-23 15:34 ` [RFC PATCH 04/11] mm/hmm: Simplify hmm_get_or_create and make it reliable Jason Gunthorpe
2019-05-23 23:38 ` Ralph Campbell
2019-05-24 1:23 ` Jason Gunthorpe
2019-05-24 17:06 ` Ralph Campbell
2019-05-23 15:34 ` [RFC PATCH 05/11] mm/hmm: Improve locking around hmm->dead Jason Gunthorpe
2019-05-24 13:40 ` Jason Gunthorpe
2019-05-23 15:34 ` [RFC PATCH 06/11] mm/hmm: Remove duplicate condition test before wait_event_timeout Jason Gunthorpe
2019-05-23 15:34 ` [RFC PATCH 07/11] mm/hmm: Delete hmm_mirror_mm_is_alive() Jason Gunthorpe
2019-05-23 15:34 ` [RFC PATCH 08/11] mm/hmm: Use lockdep instead of comments Jason Gunthorpe
2019-06-07 19:33 ` Souptick Joarder
2019-06-07 19:39 ` Jason Gunthorpe
2019-06-07 21:02 ` Souptick Joarder
2019-06-08 1:15 ` Jason Gunthorpe
2019-05-23 15:34 ` [RFC PATCH 09/11] mm/hmm: Remove racy protection against double-unregistration Jason Gunthorpe
2019-06-07 19:38 ` Souptick Joarder
2019-06-07 19:37 ` Jason Gunthorpe
2019-06-07 19:55 ` Souptick Joarder
2019-05-23 15:34 ` [RFC PATCH 10/11] mm/hmm: Poison hmm_range during unregister Jason Gunthorpe
2019-06-07 20:13 ` Souptick Joarder
2019-06-07 20:18 ` Jason Gunthorpe
2019-05-23 15:34 ` [RFC PATCH 11/11] mm/hmm: Do not use list*_rcu() for hmm->ranges Jason Gunthorpe
2019-06-07 20:22 ` Souptick Joarder
2019-05-23 19:04 ` [RFC PATCH 00/11] mm/hmm: Various revisions from a locking/code review John Hubbard
2019-05-23 19:37 ` Jason Gunthorpe
2019-05-23 20:59 ` Jerome Glisse
2019-05-24 13:35 ` Jason Gunthorpe
2019-05-24 14:36 ` Jason Gunthorpe
2019-05-24 16:49 ` Jerome Glisse
2019-05-24 16:59 ` Jason Gunthorpe
2019-05-24 17:01 ` Jerome Glisse
2019-05-24 17:52 ` Jason Gunthorpe
2019-05-24 18:03 ` Jerome Glisse
2019-05-24 18:32 ` Jason Gunthorpe
2019-05-24 18:46 ` Jerome Glisse
2019-05-24 22:09 ` Jason Gunthorpe
2019-05-27 19:58 ` Jason Gunthorpe
2019-05-24 17:47 ` Ralph Campbell
2019-05-24 17:51 ` Jerome Glisse
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