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authorJason Gunthorpe <jgg@mellanox.com>2020-05-01 21:20:45 +0300
committerJason Gunthorpe <jgg@mellanox.com>2020-05-11 16:47:29 +0300
commitbe957c886d92aa9caf0f63aee2c77d1497217d93 (patch)
tree945037adedcbcdbf4f3f6e309334d1c0eb583e3f /Documentation/vm/hmm.rst
parent0e698dfa282211e414076f9dc7e83c1c288314fd (diff)
downloadlinux-be957c886d92aa9caf0f63aee2c77d1497217d93.tar.xz
mm/hmm: make hmm_range_fault return 0 or -1
hmm_vma_walk->last is supposed to be updated after every write to the pfns, so that it can be returned by hmm_range_fault(). However, this is not done consistently. Fortunately nothing checks the return code of hmm_range_fault() for anything other than error. More importantly last must be set before returning -EBUSY as it is used to prevent reading an output pfn as an input flags when the loop restarts. For clarity and simplicity make hmm_range_fault() return 0 or -ERRNO. Only set last when returning -EBUSY. Link: https://lore.kernel.org/r/2-v2-b4e84f444c7d+24f57-hmm_no_flags_jgg@mellanox.com Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> Tested-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'Documentation/vm/hmm.rst')
-rw-r--r--Documentation/vm/hmm.rst2
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/vm/hmm.rst b/Documentation/vm/hmm.rst
index 4e3e9362afeb..9924f2caa018 100644
--- a/Documentation/vm/hmm.rst
+++ b/Documentation/vm/hmm.rst
@@ -161,7 +161,7 @@ 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::
- long hmm_range_fault(struct hmm_range *range);
+ int hmm_range_fault(struct hmm_range *range);
It will 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