From: Arnd Bergmann <arnd@arndb.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
linux-aio <linux-aio@kvack.org>,
linux-block <linux-block@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>, Jeff Moyer <jmoyer@redhat.com>,
Avi Kivity <avi@scylladb.com>
Subject: Re: [PATCH 05/16] Add io_uring IO interface
Date: Wed, 16 Jan 2019 12:00:40 +0100 [thread overview]
Message-ID: <CAK8P3a1=-=8YZ+9wsCGJ+gS3G5axHAKXA4XVcEQnyzwHD6fO6A@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a19ie7wcndDW7oxmUGh5c9aaarJycKBVOQ2F9+eHj=nsg@mail.gmail.com>
On Wed, Jan 16, 2019 at 11:41 AM Arnd Bergmann <arnd@arndb.de> wrote:
> > +/*
> > + * IO submission data structure (Submission Queue Entry)
> > + */
> > +struct io_uring_sqe {
> > + __u8 opcode; /* type of operation for this sqe */
> > + __u8 flags; /* as of now unused */
> > + __u16 ioprio; /* ioprio for the request */
> > + __s32 fd; /* file descriptor to do IO on */
> > + __u64 off; /* offset into file */
> > + union {
> > + void *addr; /* buffer or iovecs */
> > + __u64 __pad;
> > + };
>
> It seems a bit unfortunate to keep the pointer field only
> almost compatible between 32-bit and 64-bit big-endian
> architectures, as that requires an in_compat_syscall()
> check whenever we access the pointer from the kernel.
>
> Could you use a __u64 field to store the pointer itself
> instead?
To clarify: Using the u64_to_user_ptr() helper function,
you can interpret a __u64 field in a uapi data structure
directly as a pointer. The user space side needs a similar
wrapper though.
Arnd
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WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
linux-aio <linux-aio@kvack.org>,
linux-block <linux-block@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>, Jeff Moyer <jmoyer@redhat.com>,
Avi Kivity <avi@scylladb.com>
Subject: Re: [PATCH 05/16] Add io_uring IO interface
Date: Wed, 16 Jan 2019 12:00:40 +0100 [thread overview]
Message-ID: <CAK8P3a1=-=8YZ+9wsCGJ+gS3G5axHAKXA4XVcEQnyzwHD6fO6A@mail.gmail.com> (raw)
Message-ID: <20190116110040.ceJhy4Ug07iNk-2w0IZy0coli4TbtsvMRKUUIqrUPKc@z> (raw)
In-Reply-To: <CAK8P3a19ie7wcndDW7oxmUGh5c9aaarJycKBVOQ2F9+eHj=nsg@mail.gmail.com>
On Wed, Jan 16, 2019 at 11:41 AM Arnd Bergmann <arnd@arndb.de> wrote:
> > +/*
> > + * IO submission data structure (Submission Queue Entry)
> > + */
> > +struct io_uring_sqe {
> > + __u8 opcode; /* type of operation for this sqe */
> > + __u8 flags; /* as of now unused */
> > + __u16 ioprio; /* ioprio for the request */
> > + __s32 fd; /* file descriptor to do IO on */
> > + __u64 off; /* offset into file */
> > + union {
> > + void *addr; /* buffer or iovecs */
> > + __u64 __pad;
> > + };
>
> It seems a bit unfortunate to keep the pointer field only
> almost compatible between 32-bit and 64-bit big-endian
> architectures, as that requires an in_compat_syscall()
> check whenever we access the pointer from the kernel.
>
> Could you use a __u64 field to store the pointer itself
> instead?
To clarify: Using the u64_to_user_ptr() helper function,
you can interpret a __u64 field in a uapi data structure
directly as a pointer. The user space side needs a similar
wrapper though.
Arnd
next prev parent reply other threads:[~2019-01-16 11:00 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-15 2:55 (unknown), Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 01/16] fs: add an iopoll method to struct file_operations Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 02/16] block: wire up block device iopoll method Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 03/16] block: add bio_set_polled() helper Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 04/16] iomap: wire up the iopoll method Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 05/16] Add io_uring IO interface Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 16:51 ` Jonathan Corbet
2019-01-15 16:51 ` Jonathan Corbet
2019-01-15 16:55 ` Jens Axboe
2019-01-15 16:55 ` Jens Axboe
2019-01-15 17:26 ` Jens Axboe
2019-01-15 17:26 ` Jens Axboe
2019-01-16 10:41 ` Arnd Bergmann
2019-01-16 10:41 ` Arnd Bergmann
2019-01-16 11:00 ` Arnd Bergmann [this message]
2019-01-16 11:00 ` Arnd Bergmann
2019-01-16 15:12 ` Jens Axboe
2019-01-16 15:12 ` Jens Axboe
2019-01-16 15:16 ` Arnd Bergmann
2019-01-16 15:16 ` Arnd Bergmann
2019-01-16 15:25 ` Jens Axboe
2019-01-16 15:25 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 06/16] io_uring: add fsync support Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 07/16] io_uring: support for IO polling Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 08/16] io_uring: add submission side request cache Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 09/16] fs: add fget_many() and fput_many() Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 10/16] io_uring: use fget/fput_many() for file references Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 11/16] io_uring: batch io_kiocb allocation Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 12/16] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-16 10:53 ` Arnd Bergmann
2019-01-16 15:14 ` Jens Axboe
2019-01-16 15:14 ` Jens Axboe
2019-01-16 15:32 ` Jens Axboe
2019-01-16 15:32 ` Jens Axboe
2019-01-16 15:41 ` Arnd Bergmann
2019-01-16 15:47 ` Jens Axboe
2019-01-16 15:47 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 14/16] io_uring: add submission polling Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 15/16] io_uring: add file registration Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-16 10:45 ` Arnd Bergmann
2019-01-16 10:45 ` Arnd Bergmann
2019-01-16 15:15 ` Jens Axboe
2019-01-16 15:15 ` Jens Axboe
2019-01-15 2:55 ` [PATCH 16/16] io_uring: add io_uring_event cache hit information Jens Axboe
2019-01-15 2:55 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2019-01-12 21:29 [PATCHSET v3] io_uring IO interface Jens Axboe
2019-01-12 21:30 ` [PATCH 05/16] Add " Jens Axboe
2019-01-12 21:30 ` Jens Axboe
2019-01-08 16:56 [PATCHSET v1] " Jens Axboe
2019-01-08 16:56 ` [PATCH 05/16] Add " Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-09 12:10 ` Christoph Hellwig
2019-01-09 15:53 ` Jens Axboe
2019-01-09 15:53 ` Jens Axboe
2019-01-09 18:30 ` Christoph Hellwig
2019-01-09 18:30 ` Christoph Hellwig
2019-01-09 20:07 ` Jens Axboe
2019-01-09 20:07 ` Jens Axboe
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