Commit 378a6040 authored May 23, 2019 by Jason Gunthorpe

mm/hmm: Remove duplicate condition test before wait_event_timeout



The wait_event_timeout macro already tests the condition as its first
action, so there is no reason to open code another version of this, all
that does is skip the might_sleep() debugging in common cases, which is
not helpful.

Further, based on prior patches, we can now simplify the required condition
test:
 - If range is valid memory then so is range->hmm
 - If hmm_release() has run then range->valid is set to false
   at the same time as dead, so no reason to check both.
 - A valid hmm has a valid hmm->mm.

Allowing the return value of wait_event_timeout() (along with its internal
barriers) to compute the result of the function.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@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>

parent 8a9320b7

include/linux/hmm.h

+2 −11

Original line number	Diff line number	Diff line
		@@ -209,17 +209,8 @@ static inline unsigned long hmm_range_page_size(const struct hmm_range *range)
		static inline bool hmm_range_wait_until_valid(struct hmm_range *range,
		unsigned long timeout)
		{
		/* Check if mm is dead ? */
		if (range->hmm == NULL \|\| range->hmm->dead \|\| range->hmm->mm == NULL) {
		range->valid = false;
		return false;
		}
		if (range->valid)
		return true;
		wait_event_timeout(range->hmm->wq, range->valid \|\| range->hmm->dead,
		msecs_to_jiffies(timeout));
		/* Return current valid status just in case we get lucky */
		return range->valid;
		return wait_event_timeout(range->hmm->wq, range->valid,
		msecs_to_jiffies(timeout)) != 0;
		}

		/*

Admin message