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author | Christoph Hellwig <hch@lst.de> | 2019-07-25 17:56:47 -0700 |
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committer | Jason Gunthorpe <jgg@mellanox.com> | 2019-07-26 11:10:53 -0300 |
commit | d45d464b118f428229d91769c8a3cc1e2e0bb4d5 (patch) | |
tree | 2cc3f6a9435790fb3038c840e77dea66ffb45323 /Documentation/vm/hmm.rst | |
parent | 9a4903e49e495bfd2650862dfae4178bebe4db9c (diff) | |
download | linux-d45d464b118f428229d91769c8a3cc1e2e0bb4d5.tar.bz2 |
mm/hmm: merge hmm_range_snapshot into hmm_range_fault
Add a HMM_FAULT_SNAPSHOT flag so that hmm_range_snapshot can be merged
into the almost identical hmm_range_fault function.
Link: https://lore.kernel.org/r/20190726005650.2566-5-rcampbell@nvidia.com
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'Documentation/vm/hmm.rst')
-rw-r--r-- | Documentation/vm/hmm.rst | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/Documentation/vm/hmm.rst b/Documentation/vm/hmm.rst index 710ce1c701bf..ddcb5ca8b296 100644 --- a/Documentation/vm/hmm.rst +++ b/Documentation/vm/hmm.rst @@ -192,15 +192,14 @@ read only, or fully unmap, etc.). The device must complete the update before the driver callback returns. When the device driver wants to populate a range of virtual addresses, it can -use either:: +use:: - long hmm_range_snapshot(struct hmm_range *range); - long hmm_range_fault(struct hmm_range *range, bool block); + long hmm_range_fault(struct hmm_range *range, unsigned int flags); -The first one (hmm_range_snapshot()) will only fetch present CPU page table +With the HMM_RANGE_SNAPSHOT flag, it will only fetch present CPU page table entries and will not trigger a page fault on missing or non-present entries. -The second one does trigger a page fault on missing or read-only entries if -write access is requested (see below). Page faults use the generic mm page +Without that flag, it does trigger a page fault on missing or read-only entries +if write access is requested (see below). Page faults use the generic mm page fault code path just like a CPU page fault. Both functions copy CPU page table entries into their pfns array argument. Each @@ -227,20 +226,20 @@ The usage pattern is:: /* * Just wait for range to be valid, safe to ignore return value as we - * will use the return value of hmm_range_snapshot() below under the + * will use the return value of hmm_range_fault() below under the * mmap_sem to ascertain the validity of the range. */ hmm_range_wait_until_valid(&range, TIMEOUT_IN_MSEC); again: down_read(&mm->mmap_sem); - ret = hmm_range_snapshot(&range); + ret = hmm_range_fault(&range, HMM_RANGE_SNAPSHOT); if (ret) { up_read(&mm->mmap_sem); 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() + * on retry we will get proper error with hmm_range_fault() */ hmm_range_wait_until_valid(&range, TIMEOUT_IN_MSEC); goto again; |