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authorJason Gunthorpe <jgg@mellanox.com>2019-05-23 09:41:19 -0300
committerJason Gunthorpe <jgg@mellanox.com>2019-06-10 10:10:30 -0300
commite36acfe6c86d13eec62321e1e86a1ce287e52e7d (patch)
treedce3ca3311aa436c629a5443b126dd73865177df /mm/hmm.c
parent6d7c3cde93c1d9ac0b37f78ec3f2ff052159a242 (diff)
downloadlinux-e36acfe6c86d13eec62321e1e86a1ce287e52e7d.tar.bz2
mm/hmm: Use hmm_mirror not mm as an argument for hmm_range_register
Ralph observes that hmm_range_register() 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> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Philip Yang <Philip.Yang@amd.com>
Diffstat (limited to 'mm/hmm.c')
-rw-r--r--mm/hmm.c13
1 files changed, 4 insertions, 9 deletions
diff --git a/mm/hmm.c b/mm/hmm.c
index f6956d78e3cb..22a97ada108b 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -914,13 +914,13 @@ 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)
{
unsigned long mask = ((1UL << page_shift) - 1UL);
- struct hmm *hmm;
+ struct hmm *hmm = mirror->hmm;
range->valid = false;
range->hmm = NULL;
@@ -934,20 +934,15 @@ int hmm_range_register(struct hmm_range *range,
range->start = start;
range->end = end;
- hmm = hmm_get_or_create(mm);
- if (!hmm)
- return -EFAULT;
-
/* Check if hmm_mm_destroy() was call. */
- if (hmm->mm == NULL || hmm->dead) {
- hmm_put(hmm);
+ if (hmm->mm == NULL || hmm->dead)
return -EFAULT;
- }
/* Initialize range to track CPU page table updates. */
mutex_lock(&hmm->lock);
range->hmm = hmm;
+ kref_get(&hmm->kref);
list_add_rcu(&range->list, &hmm->ranges);
/*