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From: Roman Penyaev <rpenyaev@suse.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
	linux-block@vger.kernel.org, hch@lst.de, jmoyer@redhat.com,
	avi@scylladb.com, linux-block-owner@vger.kernel.org
Subject: Re: [PATCH 05/17] Add io_uring IO interface
Date: Mon, 21 Jan 2019 10:13:32 +0100	[thread overview]
Message-ID: <20204806b30147da55990e639586cce1@suse.de> (raw)
In-Reply-To: <20190118161225.4545-6-axboe@kernel.dk>

On 2019-01-18 17:12, Jens Axboe wrote:

[...]

> +
> +static int io_uring_create(unsigned entries, struct io_uring_params 
> *p,
> +			   bool compat)
> +{
> +	struct user_struct *user = NULL;
> +	struct io_ring_ctx *ctx;
> +	int ret;
> +
> +	if (entries > IORING_MAX_ENTRIES)
> +		return -EINVAL;
> +
> +	/*
> +	 * Use twice as many entries for the CQ ring. It's possible for the
> +	 * application to drive a higher depth than the size of the SQ ring,
> +	 * since the sqes are only used at submission time. This allows for
> +	 * some flexibility in overcommitting a bit.
> +	 */
> +	p->sq_entries = roundup_pow_of_two(entries);
> +	p->cq_entries = 2 * p->sq_entries;
> +
> +	if (!capable(CAP_IPC_LOCK)) {
> +		user = get_uid(current_user());
> +		ret = __io_account_mem(user, ring_pages(p->sq_entries,
> +							p->cq_entries));
> +		if (ret) {
> +			free_uid(user);
> +			return ret;
> +		}
> +	}
> +
> +	ctx = io_ring_ctx_alloc(p);
> +	if (!ctx)
> +		return -ENOMEM;

Hi Jens,

It seems pages should be "unaccounted" back here and uid freed if path
with "if (!capable(CAP_IPC_LOCK))" above was taken.

But really, could please someone explain me what is wrong with 
allocating
all urings in mmap() without touching RLIMIT_MEMLOCK at all?  Thus all
memory will be accounted to the caller app and if app is greedy it will
be killed by oom.  What I'm missing?

--
Roman



  reply	other threads:[~2019-01-21  9:13 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-18 16:12 [PATCHSET v6] io_uring IO interface Jens Axboe
2019-01-18 16:12 ` [PATCH 01/17] fs: add an iopoll method to struct file_operations Jens Axboe
2019-01-18 16:12 ` [PATCH 02/17] block: wire up block device iopoll method Jens Axboe
2019-01-18 16:12 ` [PATCH 03/17] block: add bio_set_polled() helper Jens Axboe
2019-01-18 16:12 ` [PATCH 04/17] iomap: wire up the iopoll method Jens Axboe
2019-01-18 16:12 ` [PATCH 05/17] Add io_uring IO interface Jens Axboe
2019-01-21  9:13   ` Roman Penyaev [this message]
2019-01-21 15:30     ` Jens Axboe
2019-01-21 15:58       ` Roman Penyaev
2019-01-21 16:23         ` Jens Axboe
2019-01-21 16:49           ` Roman Penyaev
2019-01-22 16:11             ` Jens Axboe
2019-01-18 16:12 ` [PATCH 06/17] io_uring: add fsync support Jens Axboe
2019-01-18 16:12 ` [PATCH 07/17] io_uring: support for IO polling Jens Axboe
2019-01-18 16:12 ` [PATCH 08/17] fs: add fget_many() and fput_many() Jens Axboe
2019-01-18 16:12 ` [PATCH 09/17] io_uring: use fget/fput_many() for file references Jens Axboe
2019-01-18 16:12 ` [PATCH 10/17] io_uring: batch io_kiocb allocation Jens Axboe
2019-01-18 16:12 ` [PATCH 11/17] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2019-01-18 16:12 ` [PATCH 12/17] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-18 16:12 ` [PATCH 13/17] io_uring: add file set registration Jens Axboe
2019-01-18 16:12 ` [PATCH 14/17] io_uring: add submission polling Jens Axboe
2019-01-18 16:12 ` [PATCH 15/17] io_uring: add io_kiocb ref count Jens Axboe
2019-01-18 16:12 ` [PATCH 16/17] io_uring: add support for IORING_OP_POLL Jens Axboe
2019-01-18 16:12 ` [PATCH 17/17] io_uring: add io_uring_event cache hit information Jens Axboe

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