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Dan Williams authored
Users reported a v5.3 performance regression and inability to establish huge page mappings. A revised version of the ndctl "dax.sh" huge page unit test identifies commit 23c84eb7 "dax: Fix missed wakeup with PMD faults" as the source. Update get_unlocked_entry() to check for NULL entries before checking the entry order, otherwise NULL is misinterpreted as a present pte conflict. The 'order' check needs to happen before the locked check as an unlocked entry at the wrong order must fallback to lookup the correct order. Reported-by:
Jeff Smits <jeff.smits@intel.com> Reported-by:
Doug Nelson <doug.nelson@intel.com> Cc: <stable@vger.kernel.org> Fixes: 23c84eb7 ("dax: Fix missed wakeup with PMD faults") Reviewed-by:
Jan Kara <jack@suse.cz> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by:
Johannes Thumshirn <jthumshirn@suse.de> Link: https://lore.kernel.org/r/157167532455.3945484.11971474077040503994.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by:
Dan Williams <dan.j.williams@intel.com>
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