Re: [PATCH v4 07/12] dax: coordinate locking for offsets in PMD range

Christoph Hellwig
2016-09-30T09:44:33Z

> +static pgoff_t dax_entry_start(pgoff_t index, void *entry)
> +{
> + if (RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD)
> + index &= (PMD_MASK >> PAGE_SHIFT);
> + return index;
> +}
> +
> static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping,
> - pgoff_t index)
> + pgoff_t entry_start)
> {
> - unsigned long hash = hash_long((unsigned long)mapping ^ index,
> + unsigned long hash = hash_long((unsigned long)mapping ^ entry_start,
> DAX_WAIT_TABLE_BITS);
> return wait_table + hash;
> }

All callers of dax_entry_waitqueue need to calculate entry_start
using this new dax_entry_start helper. Either we should move the
call to dax_entry_start into this helper. Or at least use local
variables for in the callers as both of them also fill out a
wait_exceptional_entry_queue structure with it. Or do both by
letting dax_entry_waitqueue fill out that structure as well.