From: Christoph Hellwig <hch@lst.de>
To: "Jérôme Glisse" <jglisse@redhat.com>,
"Jason Gunthorpe" <jgg@mellanox.com>,
"Ben Skeggs" <bskeggs@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>,
linux-mm@kvack.org, nouveau@lists.freedesktop.org,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
Felix Kuehling <Felix.Kuehling@amd.com>
Subject: [PATCH 1/7] mm: always return EBUSY for invalid ranges in hmm_range_{fault,snapshot}
Date: Wed, 24 Jul 2019 08:52:52 +0200 [thread overview]
Message-ID: <20190724065258.16603-2-hch@lst.de> (raw)
In-Reply-To: <20190724065258.16603-1-hch@lst.de>
We should not have two different error codes for the same condition. In
addition this really complicates the code due to the special handling of
EAGAIN that drops the mmap_sem due to the FAULT_FLAG_ALLOW_RETRY logic
in the core vm.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
Documentation/vm/hmm.rst | 2 +-
mm/hmm.c | 10 ++++------
2 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/Documentation/vm/hmm.rst b/Documentation/vm/hmm.rst
index 7d90964abbb0..710ce1c701bf 100644
--- a/Documentation/vm/hmm.rst
+++ b/Documentation/vm/hmm.rst
@@ -237,7 +237,7 @@ The usage pattern is::
ret = hmm_range_snapshot(&range);
if (ret) {
up_read(&mm->mmap_sem);
- if (ret == -EAGAIN) {
+ if (ret == -EBUSY) {
/*
* No need to check hmm_range_wait_until_valid() return value
* on retry we will get proper error with hmm_range_snapshot()
diff --git a/mm/hmm.c b/mm/hmm.c
index e1eedef129cf..16b6731a34db 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -946,7 +946,7 @@ EXPORT_SYMBOL(hmm_range_unregister);
* @range: range
* Return: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid
* permission (for instance asking for write and range is read only),
- * -EAGAIN if you need to retry, -EFAULT invalid (ie either no valid
+ * -EBUSY if you need to retry, -EFAULT invalid (ie either no valid
* vma or it is illegal to access that range), number of valid pages
* in range->pfns[] (from range start address).
*
@@ -967,7 +967,7 @@ long hmm_range_snapshot(struct hmm_range *range)
do {
/* If range is no longer valid force retry. */
if (!range->valid)
- return -EAGAIN;
+ return -EBUSY;
vma = find_vma(hmm->mm, start);
if (vma == NULL || (vma->vm_flags & device_vma))
@@ -1062,10 +1062,8 @@ long hmm_range_fault(struct hmm_range *range, bool block)
do {
/* If range is no longer valid force retry. */
- if (!range->valid) {
- up_read(&hmm->mm->mmap_sem);
- return -EAGAIN;
- }
+ if (!range->valid)
+ return -EBUSY;
vma = find_vma(hmm->mm, start);
if (vma == NULL || (vma->vm_flags & device_vma))
--
2.20.1
next prev parent reply other threads:[~2019-07-24 6:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-24 6:52 hmm_range_fault related fixes and legacy API removal v3 Christoph Hellwig
2019-07-24 6:52 ` Christoph Hellwig [this message]
[not found] ` <20190724065258.16603-1-hch-jcswGhMUV9g@public.gmane.org>
2019-07-24 6:52 ` [PATCH 2/7] mm: move hmm_vma_range_done and hmm_vma_fault to nouveau Christoph Hellwig
2019-07-24 6:52 ` [PATCH 3/7] nouveau: remove the block parameter to nouveau_range_fault Christoph Hellwig
2019-07-24 6:52 ` [PATCH 4/7] nouveau: unlock mmap_sem on all errors from nouveau_range_fault Christoph Hellwig
2019-07-24 6:52 ` [PATCH 5/7] nouveau: return -EBUSY when hmm_range_wait_until_valid fails Christoph Hellwig
2019-07-24 6:52 ` [PATCH 6/7] mm: remove the legacy hmm_pfn_* APIs Christoph Hellwig
2019-07-24 6:52 ` [PATCH 7/7] mm: comment on VM_FAULT_RETRY semantics in handle_mm_fault Christoph Hellwig
2019-07-26 0:16 ` hmm_range_fault related fixes and legacy API removal v3 Jason Gunthorpe
2019-07-26 0:55 ` Ralph Campbell
[not found] ` <20190726001622.GL7450-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2019-07-26 4:57 ` Christoph Hellwig
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