public inbox for [email protected]
 help / color / mirror / Atom feed
From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>, [email protected]
Cc: "Franz-B . Tuneke" <[email protected]>
Subject: Re: [PATCH v2 5.15] io_uring: auto-removal for direct open/accept
Date: Tue, 14 Sep 2021 16:48:37 +0100	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 9/14/21 4:36 PM, Jens Axboe wrote:
> On 9/14/21 9:12 AM, Pavel Begunkov wrote:
>> It might be inconvenient that direct open/accept deviates from the
>> update semantics and fails if the slot is taken instead of removing a
>> file sitting there. Implement this auto-removal.
>>
>> Note that removal might need to allocate and so may fail. However, if an
>> empty slot is specified, it's guaraneed to not fail on the fd
>> installation side for valid userspace programs. It's needed for users
>> who can't tolerate such failures, e.g. accept where the other end
>> never retries.
>>
>> Suggested-by: Franz-B. Tuneke <[email protected]>
>> Signed-off-by: Pavel Begunkov <[email protected]>
>> ---
>>
>> v2: simplify io_rsrc_node_switch_start() handling
>>
>>  fs/io_uring.c | 52 +++++++++++++++++++++++++++++++++------------------
>>  1 file changed, 34 insertions(+), 18 deletions(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index a864a94364c6..58c0cbfdd128 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -8287,11 +8287,27 @@ static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
>>  #endif
>>  }
>>  
>> +static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
>> +				 struct io_rsrc_node *node, void *rsrc)
>> +{
>> +	struct io_rsrc_put *prsrc;
>> +
>> +	prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
>> +	if (!prsrc)
>> +		return -ENOMEM;
>> +
>> +	prsrc->tag = *io_get_tag_slot(data, idx);
>> +	prsrc->rsrc = rsrc;
>> +	list_add(&prsrc->list, &node->rsrc_list);
>> +	return 0;
>> +}
> 
> I know this code is just being moved, but I tend to like making the
> expected/fast path inline:

I think it's more natural as now, as we always have

ret = do_something();
if (ret)
    return ret;
ret = do_something2();
if (ret)
    goto err;


And I remember you telling once "... I tend to like to do the error
path like that unless it's a hot path ...". So maybe just add
unlikely()?


> prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
> if (prsrc) {
> 	prsrc->tag = *io_get_tag_slot(data, idx);
> 	prsrc->rsrc = rsrc;
> 	list_add(&prsrc->list, &node->rsrc_list);
> 	return 0;
> }
> return -ENOMEM;
> 

-- 
Pavel Begunkov

  reply	other threads:[~2021-09-14 15:49 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-14 15:12 [PATCH v2 5.15] io_uring: auto-removal for direct open/accept Pavel Begunkov
2021-09-14 15:14 ` Jens Axboe
2021-09-14 15:21   ` Pavel Begunkov
2021-09-14 15:36 ` Jens Axboe
2021-09-14 15:48   ` Pavel Begunkov [this message]
2021-09-14 15:50     ` Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox