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From: Jeff Moyer <jmoyer@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-aio@kvack.org, linux-block@vger.kernel.org,
	linux-api@vger.kernel.org, hch@lst.de, avi@scylladb.com,
	jannh@google.com, viro@ZenIV.linux.org.uk
Subject: Re: [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers
Date: Thu, 07 Feb 2019 17:38:34 -0500	[thread overview]
Message-ID: <x49zhr7442d.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <20190207195552.22770-13-axboe@kernel.dk> (Jens Axboe's message of "Thu, 7 Feb 2019 12:55:46 -0700")

Hi, Jens,

Jens Axboe <axboe@kernel.dk> writes:

> For now, buffers must not be file backed. If file backed buffers are
> passed in, the registration will fail with -1/EOPNOTSUPP. This
> restriction may be relaxed in the future.

[...]

> +		down_write(&current->mm->mmap_sem);
> +		pret = get_user_pages_longterm(ubuf, nr_pages, FOLL_WRITE,
> +						pages, vmas);
> +		if (pret == nr_pages) {
> +			/* don't support file backed memory */
> +			for (j = 0; j < nr_pages; j++) {
> +				struct vm_area_struct *vma = vmas[j];
> +
> +				if (vma->vm_file) {
> +					ret = -EOPNOTSUPP;
> +					break;
> +				}
> +			}

Unfortunately, this suffers the same problem as FOLL_ANON.  Huge pages
are backed by hugetlbfs, and vma->vm_file will be filled in.

I guess you could check is_file_hugepages(vma->vm_file):

        if (vma->vm_file &&
            !is_file_hugepages(vma->vm_file)) {
                ret = -EOPNOTSUPP;
                break;
       }

That works for me.

-Jeff

  parent reply	other threads:[~2019-02-07 22:38 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-07 19:55 [PATCHSET v12] io_uring IO interface Jens Axboe
2019-02-07 19:55 ` [PATCH 01/18] fs: add an iopoll method to struct file_operations Jens Axboe
2019-02-07 19:55 ` [PATCH 02/18] block: wire up block device iopoll method Jens Axboe
2019-02-07 19:55 ` [PATCH 03/18] block: add bio_set_polled() helper Jens Axboe
2019-02-07 19:55 ` [PATCH 04/18] iomap: wire up the iopoll method Jens Axboe
2019-02-07 19:55 ` [PATCH 05/18] Add io_uring IO interface Jens Axboe
2019-02-07 20:15   ` Keith Busch
2019-02-07 20:16     ` Jens Axboe
2019-02-07 19:55 ` [PATCH 06/18] io_uring: add fsync support Jens Axboe
2019-02-07 19:55 ` [PATCH 07/18] io_uring: support for IO polling Jens Axboe
2019-02-07 19:55 ` [PATCH 08/18] fs: add fget_many() and fput_many() Jens Axboe
2019-02-07 19:55 ` [PATCH 09/18] io_uring: use fget/fput_many() for file references Jens Axboe
2019-02-07 19:55 ` [PATCH 10/18] io_uring: batch io_kiocb allocation Jens Axboe
2019-02-07 19:55 ` [PATCH 11/18] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2019-02-07 19:55 ` [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-02-07 20:57   ` Jeff Moyer
2019-02-07 21:02     ` Jens Axboe
2019-02-07 22:38   ` Jeff Moyer [this message]
2019-02-07 22:47     ` Jens Axboe
2019-02-07 19:55 ` [PATCH 13/18] io_uring: add file set registration Jens Axboe
2019-02-08 12:17   ` Alan Jenkins
2019-02-08 12:57     ` Jens Axboe
2019-02-08 14:02       ` Alan Jenkins
2019-02-08 15:13         ` Jens Axboe
2019-02-12 12:29           ` Alan Jenkins
2019-02-12 15:17             ` Jens Axboe
2019-02-12 17:21               ` Alan Jenkins
2019-02-12 17:33                 ` Jens Axboe
2019-02-12 20:23                   ` Alan Jenkins
2019-02-12 21:10                     ` Jens Axboe
2019-02-07 19:55 ` [PATCH 14/18] io_uring: add submission polling Jens Axboe
2019-02-07 19:55 ` [PATCH 15/18] io_uring: add io_kiocb ref count Jens Axboe
2019-02-07 19:55 ` [PATCH 16/18] io_uring: add support for IORING_OP_POLL Jens Axboe
2019-02-07 22:12   ` Jeff Moyer
2019-02-07 22:18     ` Jens Axboe
2019-02-07 19:55 ` [PATCH 17/18] io_uring: allow workqueue item to handle multiple buffered requests Jens Axboe
2019-02-07 19:55 ` [PATCH 18/18] io_uring: add io_uring_event cache hit information Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2019-02-01 15:23 [PATCHSET v11] io_uring IO interface Jens Axboe
2019-02-01 15:24 ` [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-30 21:55 [PATCHSET v10] io_uring IO interface Jens Axboe
2019-01-30 21:55 ` [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-29 19:26 [PATCHSET v9] io_uring IO interface Jens Axboe
2019-01-29 19:26 ` [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-29 22:44   ` Jann Horn
2019-01-29 22:56     ` Jens Axboe
2019-01-29 23:03       ` Jann Horn
2019-01-29 23:06         ` Jens Axboe
2019-01-29 23:08           ` Jann Horn
2019-01-29 23:14             ` Jens Axboe
2019-01-29 23:42               ` Jann Horn
2019-01-29 23:51                 ` Jens Axboe
2019-01-28 21:35 [PATCHSET v8] io_uring IO interface Jens Axboe
2019-01-28 21:35 ` [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-28 23:35   ` Jann Horn
2019-01-28 23:50     ` Jens Axboe
2019-01-29  0:36       ` Jann Horn
2019-01-29  1:25         ` Jens Axboe
2019-01-23 15:35 [PATCHSET v7] io_uring IO interface Jens Axboe
2019-01-23 15:35 ` [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers Jens Axboe

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