From: John Hubbard <jhubbard@xxxxxxxxxx> Convert the fuse filesystem to support the new iov_iter_get_pages() behavior. That routine now invokes pin_user_pages_fast(), which means that such pages must be released via unpin_user_page(), rather than via put_page(). This commit also removes any possibility of kernel pages being handled, in the fuse_get_user_pages() call. Although this may seem like a steep price to pay, Christoph Hellwig actually recommended it a few years ago for nearly the same situation [1]. [1] https://lore.kernel.org/kvm/20190724061750.GA19397@xxxxxxxxxxxxx/ Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx> --- fs/fuse/dev.c | 7 +++++-- fs/fuse/file.c | 38 +++++++++----------------------------- 2 files changed, 14 insertions(+), 31 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index e1b4a846c90d..9db85c4d549a 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -675,7 +675,10 @@ static void fuse_copy_finish(struct fuse_copy_state *cs) flush_dcache_page(cs->pg); set_page_dirty_lock(cs->pg); } - put_page(cs->pg); + if (cs->pipebufs) + put_page(cs->pg); + else + unpin_user_page(cs->pg); } cs->pg = NULL; } @@ -730,7 +733,7 @@ static int fuse_copy_fill(struct fuse_copy_state *cs) } } else { size_t off; - err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off); + err = iov_iter_pin_pages(cs->iter, &page, PAGE_SIZE, 1, &off); if (err < 0) return err; BUG_ON(!err); diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 94747bac3489..ecfa5bdde919 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -611,18 +611,6 @@ void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos, args->out_args[0].size = count; } -static void fuse_release_user_pages(struct fuse_args_pages *ap, - bool should_dirty) -{ - unsigned int i; - - for (i = 0; i < ap->num_pages; i++) { - if (should_dirty) - set_page_dirty_lock(ap->pages[i]); - put_page(ap->pages[i]); - } -} - static void fuse_io_release(struct kref *kref) { kfree(container_of(kref, struct fuse_io_priv, refcnt)); @@ -720,7 +708,8 @@ static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args, struct fuse_io_priv *io = ia->io; ssize_t pos = -1; - fuse_release_user_pages(&ia->ap, io->should_dirty); + unpin_user_pages_dirty_lock(ia->ap.pages, ia->ap.num_pages, + io->should_dirty); if (err) { /* Nothing */ @@ -1382,25 +1371,14 @@ static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii, size_t nbytes = 0; /* # bytes already packed in req */ ssize_t ret = 0; - /* Special case for kernel I/O: can copy directly into the buffer */ - if (iov_iter_is_kvec(ii)) { - unsigned long user_addr = fuse_get_user_addr(ii); - size_t frag_size = fuse_get_frag_size(ii, *nbytesp); - - if (write) - ap->args.in_args[1].value = (void *) user_addr; - else - ap->args.out_args[0].value = (void *) user_addr; - - iov_iter_advance(ii, frag_size); - *nbytesp = frag_size; - return 0; - } + /* Only user space buffers are allowed with fuse Direct IO. */ + if (WARN_ON_ONCE(!iter_is_iovec(ii))) + return -EOPNOTSUPP; while (nbytes < *nbytesp && ap->num_pages < max_pages) { unsigned npages; size_t start; - ret = iov_iter_get_pages(ii, &ap->pages[ap->num_pages], + ret = iov_iter_pin_pages(ii, &ap->pages[ap->num_pages], *nbytesp - nbytes, max_pages - ap->num_pages, &start); @@ -1484,7 +1462,9 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter, } if (!io->async || nres < 0) { - fuse_release_user_pages(&ia->ap, io->should_dirty); + unpin_user_pages_dirty_lock(ia->ap.pages, + ia->ap.num_pages, + io->should_dirty); fuse_io_free(ia); } ia = NULL; -- 2.35.1
