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 <franz-bernhard.tuneke@xxxxxxxxxxxxxx>
>> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
>> ---
>>
>> 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
