On Sun, Mar 08 2015, Ming Lei <tom.leiming@xxxxxxxxx> wrote:
> On Tue, Feb 24, 2015 at 2:00 AM, Christoph Hellwig <hch@xxxxxx> wrote:
>> From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
>>
>> AIO_PREAD requests call ->aio_read() with iovec on caller's stack, so if
>> we are going to access it asynchronously, we'd better get ourselves
>> a copy - the one on kernel stack of aio_run_iocb() won't be there
>> anymore. function/f_fs.c take care of doing that, legacy/inode.c
>> doesn't...
>>
>> Cc: stable@xxxxxxxxxxxxxxx
>> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
but at the same time:
>> @@ -649,7 +650,14 @@ fail:
>> }
>> iocb->private = priv;
>> priv->iocb = iocb;
>> - priv->iv = iv;
>> + if (iv) {
>> + priv->iv = kmemdup(iv, nr_segs * sizeof(struct iovec),
>> + GFP_KERNEL);
>> + if (!priv->iv) {
>> + kfree(priv);
>> + goto fail;
>> + }
>> + }
>
> It should be simpler and more efficient to allocate 'iv' piggyback
> inside 'priv'.
+1
priv = kmalloc(sizeof *priv + (iv ? nr_segs * sizeof *iv : 0),
GFP_KERNEL);
…
priv->iv = iv ? (void*)(priv + 1) : NULL;
>> priv->nr_segs = nr_segs;
>> INIT_WORK(&priv->work, ep_user_copy_worker);
>>
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
ooo +--<mpn@xxxxxxxxxx>--<xmpp:mina86@xxxxxxxxxx>--ooO--(_)--Ooo--
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