From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers Date: Wed, 16 Jan 2019 08:14:17 -0700 Message-ID: <075af26b-c685-a0db-05e4-fa73f8725b8a@kernel.dk> References: <20190115025531.13985-1-axboe@kernel.dk> <20190115025531.13985-14-axboe@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: owner-linux-aio@kvack.org To: Arnd Bergmann Cc: Linux FS-devel Mailing List , linux-aio , linux-block , linux-arch , Christoph Hellwig , Jeff Moyer , Avi Kivity List-Id: linux-arch.vger.kernel.org On 1/16/19 3:53 AM, Arnd Bergmann wrote: > On Tue, Jan 15, 2019 at 3:56 AM Jens Axboe wrote: > >> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h >> index 542757a4c898..e36c264d74e8 100644 >> --- a/include/linux/syscalls.h >> +++ b/include/linux/syscalls.h >> @@ -314,6 +314,8 @@ asmlinkage long sys_io_uring_setup(u32 entries, >> struct io_uring_params __user *p); >> asmlinkage long sys_io_uring_enter(unsigned int fd, u32 to_submit, >> u32 min_complete, u32 flags); >> +asmlinkage long sys_io_uring_register(unsigned int fd, unsigned op, >> + void __user *arg); >> > > Would it be possible to make this a typed pointer instead? If this needs to > be extended later to pass a different structure, a new system call may > be better for consistency than overloading the argument in various > ways. As you can see from the later patch for registering files, it'll be used for other structs too. Feels a little silly to add an extra system call for that. I agree the void * isn't the prettiest thing in the world, but at least it allows us to extend the API without having to add even more system calls down the line. >> + * io_uring_register(2) opcodes and arguments >> + */ >> +#define IORING_REGISTER_BUFFERS 0 >> +#define IORING_UNREGISTER_BUFFERS 1 >> + >> +struct io_uring_register_buffers { >> + union { >> + struct iovec *iovecs; >> + __u64 pad; >> + }; >> + __u32 nr_iovecs; >> +}; > > As before, I'd suggest making this structure compatible between 32-bit > and 64-bit architectectures, by avoiding pointer and implied padding > fields. I'll await an answer to my previous question on that. -- Jens Axboe -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to majordomo@kvack.org. For more info on Linux AIO, see: http://www.kvack.org/aio/ Don't email: aart@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it1-f195.google.com ([209.85.166.195]:52106 "EHLO mail-it1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393958AbfAPPOX (ORCPT ); Wed, 16 Jan 2019 10:14:23 -0500 Received: by mail-it1-f195.google.com with SMTP id w18so3474576ite.1 for ; Wed, 16 Jan 2019 07:14:22 -0800 (PST) Subject: Re: [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers References: <20190115025531.13985-1-axboe@kernel.dk> <20190115025531.13985-14-axboe@kernel.dk> From: Jens Axboe Message-ID: <075af26b-c685-a0db-05e4-fa73f8725b8a@kernel.dk> Date: Wed, 16 Jan 2019 08:14:17 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arnd Bergmann Cc: Linux FS-devel Mailing List , linux-aio , linux-block , linux-arch , Christoph Hellwig , Jeff Moyer , Avi Kivity Message-ID: <20190116151417._FO4t_ryd5jZupuNb6GAgemKUu9tdY2wK0El3MA3aiw@z> On 1/16/19 3:53 AM, Arnd Bergmann wrote: > On Tue, Jan 15, 2019 at 3:56 AM Jens Axboe wrote: > >> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h >> index 542757a4c898..e36c264d74e8 100644 >> --- a/include/linux/syscalls.h >> +++ b/include/linux/syscalls.h >> @@ -314,6 +314,8 @@ asmlinkage long sys_io_uring_setup(u32 entries, >> struct io_uring_params __user *p); >> asmlinkage long sys_io_uring_enter(unsigned int fd, u32 to_submit, >> u32 min_complete, u32 flags); >> +asmlinkage long sys_io_uring_register(unsigned int fd, unsigned op, >> + void __user *arg); >> > > Would it be possible to make this a typed pointer instead? If this needs to > be extended later to pass a different structure, a new system call may > be better for consistency than overloading the argument in various > ways. As you can see from the later patch for registering files, it'll be used for other structs too. Feels a little silly to add an extra system call for that. I agree the void * isn't the prettiest thing in the world, but at least it allows us to extend the API without having to add even more system calls down the line. >> + * io_uring_register(2) opcodes and arguments >> + */ >> +#define IORING_REGISTER_BUFFERS 0 >> +#define IORING_UNREGISTER_BUFFERS 1 >> + >> +struct io_uring_register_buffers { >> + union { >> + struct iovec *iovecs; >> + __u64 pad; >> + }; >> + __u32 nr_iovecs; >> +}; > > As before, I'd suggest making this structure compatible between 32-bit > and 64-bit architectectures, by avoiding pointer and implied padding > fields. I'll await an answer to my previous question on that. -- Jens Axboe