On 8/25/22 08:24, Logan Gunthorpe wrote: > Add iov_iter_get_pages_flags() and iov_iter_get_pages_alloc_flags() > which take a flags argument that is passed to get_user_pages_fast(). > > This is so that FOLL_PCI_P2PDMA can be passed when appropriate. > > Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx> > --- > include/linux/uio.h | 6 ++++++ > lib/iov_iter.c | 40 ++++++++++++++++++++++++++++++++++++---- > 2 files changed, 42 insertions(+), 4 deletions(-) > Yes. I also don't object to Christoph's additional request to refactor and rename around iov_iter_get_pages2() and such, but this version here is perfectly good, so please feel free to add: Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx> Looking ahead, interestingly enough, it turns out that this approach to the wrappers is really pretty close to what I posted in patch 4/7 of my "convert most filesystems to pin_user_pages_fast()" series [1]. Instead of passing gup_flags through, I tried to avoid that (because FOLL_PIN is, as a mild design preference, supposed to remain internal to gup.c), but given that you need to do it, I think I can just build on top of your approach, and pass in FOLL_PIN via your new gup_flags arg. Along those lines, I've copied you in on "New topic branch for block + gup work?", let's see what happens over there. [1] https://lore.kernel.org/r/20220831041843.973026-1-jhubbard@xxxxxxxxxx thanks, -- John Hubbard NVIDIA > diff --git a/include/linux/uio.h b/include/linux/uio.h > index 5896af36199c..76ba69edb8c5 100644 > --- a/include/linux/uio.h > +++ b/include/linux/uio.h > @@ -247,8 +247,14 @@ void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode > void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count); > void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray, > loff_t start, size_t count); > +ssize_t iov_iter_get_pages_flags(struct iov_iter *i, struct page **pages, > + size_t maxsize, unsigned maxpages, size_t *start, > + unsigned int gup_flags); > ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages, > size_t maxsize, unsigned maxpages, size_t *start); > +ssize_t iov_iter_get_pages_alloc_flags(struct iov_iter *i, > + struct page ***pages, size_t maxsize, size_t *start, > + unsigned int gup_flags); > ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages, > size_t maxsize, size_t *start); > int iov_iter_npages(const struct iov_iter *i, int maxpages); > diff --git a/lib/iov_iter.c b/lib/iov_iter.c > index 4b7fce72e3e5..dedb78f3c655 100644 > --- a/lib/iov_iter.c > +++ b/lib/iov_iter.c > @@ -1427,7 +1427,8 @@ static struct page *first_bvec_segment(const struct iov_iter *i, > > static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, > struct page ***pages, size_t maxsize, > - unsigned int maxpages, size_t *start) > + unsigned int maxpages, size_t *start, > + unsigned int gup_flags) > { > unsigned int n; > > @@ -1439,7 +1440,6 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, > maxsize = MAX_RW_COUNT; > > if (likely(user_backed_iter(i))) { > - unsigned int gup_flags = 0; > unsigned long addr; > int res; > > @@ -1497,10 +1497,24 @@ ssize_t iov_iter_get_pages2(struct iov_iter *i, > return 0; > BUG_ON(!pages); > > - return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start); > + return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, > + start, 0); > } > EXPORT_SYMBOL(iov_iter_get_pages2); > > +ssize_t iov_iter_get_pages_flags(struct iov_iter *i, struct page **pages, > + size_t maxsize, unsigned maxpages, size_t *start, > + unsigned int gup_flags) > +{ > + if (!maxpages) > + return 0; > + BUG_ON(!pages); > + > + return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, > + start, gup_flags); > +} > +EXPORT_SYMBOL_GPL(iov_iter_get_pages_flags); > + > ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, > struct page ***pages, size_t maxsize, > size_t *start) > @@ -1509,7 +1523,7 @@ ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, > > *pages = NULL; > > - len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start); > + len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start, 0); > if (len <= 0) { > kvfree(*pages); > *pages = NULL; > @@ -1518,6 +1532,24 @@ ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, > } > EXPORT_SYMBOL(iov_iter_get_pages_alloc2); > > +ssize_t iov_iter_get_pages_alloc_flags(struct iov_iter *i, > + struct page ***pages, size_t maxsize, > + size_t *start, unsigned int gup_flags) > +{ > + ssize_t len; > + > + *pages = NULL; > + > + len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start, > + gup_flags); > + if (len <= 0) { > + kvfree(*pages); > + *pages = NULL; > + } > + return len; > +} > +EXPORT_SYMBOL_GPL(iov_iter_get_pages_alloc_flags); > + > size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, > struct iov_iter *i) > {
