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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Queue-Id: BE7F2C000D X-Stat-Signature: 5ksqz964f7b3pe6quqxpphyhkow7fgwj X-Rspamd-Server: rspam06 X-HE-Tag: 1775834312-904819 X-HE-Meta: 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 heicleBm 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Patrick Roy =0A= =0A= This drops an optimization in gup_fast_folio_allowed() where=0A= secretmem_mapping() was only called if CONFIG_SECRETMEM=3Dy. secretmem is= =0A= enabled by default since commit b758fe6df50d ("mm/secretmem: make it on=0A= by default"), so the secretmem check did not actually end up elided in=0A= most cases anymore anyway.=0A= =0A= To make sure the fast path for ZONE_DEVICE pages (like Device DAX and=0A= PCI P2PDMA) is still allowed, check for folio_is_zone_device() if=0A= mapping is NULL.=0A= =0A= This is in preparation of the generalization of handling mappings where=0A= direct map entries of folios are set to not present. Currently,=0A= mappings that match this description are secretmem mappings=0A= (memfd_secret()). Later, some guest_memfd configurations will also fall=0A= into this category.=0A= =0A= Signed-off-by: Patrick Roy =0A= Acked-by: Vlastimil Babka =0A= Acked-by: David Hildenbrand (Red Hat) =0A= Signed-off-by: Nikita Kalyazin =0A= ---=0A= mm/gup.c | 17 ++++++-----------=0A= 1 file changed, 6 insertions(+), 11 deletions(-)=0A= =0A= diff --git a/mm/gup.c b/mm/gup.c=0A= index 8e7dc2c6ee73..e8367564d636 100644=0A= --- a/mm/gup.c=0A= +++ b/mm/gup.c=0A= @@ -2739,7 +2739,6 @@ static bool gup_fast_folio_allowed(struct folio *foli= o, unsigned int flags)=0A= {=0A= bool reject_file_backed =3D false;=0A= struct address_space *mapping;=0A= - bool check_secretmem =3D false;=0A= unsigned long mapping_flags;=0A= =0A= /*=0A= @@ -2751,14 +2750,6 @@ static bool gup_fast_folio_allowed(struct folio *fol= io, unsigned int flags)=0A= reject_file_backed =3D true;=0A= =0A= /* We hold a folio reference, so we can safely access folio fields. */=0A= -=0A= - /* secretmem folios are always order-0 folios. */=0A= - if (IS_ENABLED(CONFIG_SECRETMEM) && !folio_test_large(folio))=0A= - check_secretmem =3D true;=0A= -=0A= - if (!reject_file_backed && !check_secretmem)=0A= - return true;=0A= -=0A= if (WARN_ON_ONCE(folio_test_slab(folio)))=0A= return false;=0A= =0A= @@ -2787,9 +2778,13 @@ static bool gup_fast_folio_allowed(struct folio *fol= io, unsigned int flags)=0A= * The mapping may have been truncated, in any case we cannot determine= =0A= * if this mapping is safe - fall back to slow path to determine how to= =0A= * proceed.=0A= + *=0A= + * ZONE_DEVICE folios (e.g. Device DAX, PCI P2PDMA) may legitimately=0A= + * have a NULL mapping. They are never secretmem/no-direct-map folios,=0A= + * so let them through.=0A= */=0A= if (!mapping)=0A= - return false;=0A= + return folio_is_zone_device(folio);=0A= =0A= /* Anonymous folios pose no problem. */=0A= mapping_flags =3D (unsigned long)mapping & FOLIO_MAPPING_FLAGS;=0A= @@ -2800,7 +2795,7 @@ static bool gup_fast_folio_allowed(struct folio *foli= o, unsigned int flags)=0A= * At this point, we know the mapping is non-null and points to an=0A= * address_space object.=0A= */=0A= - if (check_secretmem && secretmem_mapping(mapping))=0A= + if (secretmem_mapping(mapping))=0A= return false;=0A= /* The only remaining allowed file system is shmem. */=0A= return !reject_file_backed || shmem_mapping(mapping);=0A= -- =0A= 2.50.1=0A= =0A=