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Subject: Re: [PATCH v4 3/4] scsi: ufs: cleanup ufs initialization path
From:   Bean Huo <huobean@gmail.com>
To:     Avri Altman <Avri.Altman@wdc.com>,
        "alim.akhtar@samsung.com" <alim.akhtar@samsung.com>,
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        "tomas.winkler@intel.com" <tomas.winkler@intel.com>,
        "cang@codeaurora.org" <cang@codeaurora.org>
Cc:     "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
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Date:   Sun, 31 May 2020 17:11:46 +0200
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On Sat, 2020-05-30 at 06:37 +0000, Avri Altman wrote:
> > +       /* Get the length of descriptor */
> > +       ufshcd_map_desc_id_to_length(hba, desc_id, &buff_len);
> > +       if (!buff_len) {
> > +               dev_err(hba->dev, "%s: Failed to get desc length",
> > __func__);
> > +               return -EINVAL;
> >          }
> > 
> >          /* Check whether we need temp memory */
> 
> The first time we are reading the descriptor, we no longer can rely
> on its true size.
> So for this check, buff_len is 256 and kmalloc will always happen. 
> Do you think that this check is still relevant?
> 
> /* Check whether we need temp memory */
>         if (param_offset != 0 || param_size < buff_len) {
>                 desc_buf = kmalloc(buff_len, GFP_KERNEL);
>                 if (!desc_buf)
>                         return -ENOMEM;
>         } else {
>                 desc_buf = param_read_buf;
>                 is_kmalloc = false;
>         }

Avri
I found this checkup is still needed since LU descriptor read will
multiple enter this function. so I didn't delete it in the new version
patch.

thanks,
Bean