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SubjectRe: [PATCH v4 3/4] scsi: ufs: cleanup ufs initialization path
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Hi Avri
thanks your review.

On Sat, 2020-05-30 at 06:37 +0000, Avri Altman wrote:
> > - case QUERY_DESC_IDN_RFU_0:
> > - case QUERY_DESC_IDN_RFU_1:
>
> You forgot to check that desc_id < QUERY_DESC_IDN_MAX

I deleted it since I saw the caller has checked this.
I will add back.

>
>
> > + if (desc_id == QUERY_DESC_IDN_RFU_0 || desc_id ==
> > QUERY_DESC_IDN_RFU_1)
> > *desc_len = 0;
> > - break;
> > - default:
> > - *desc_len = 0;
> > - return -EINVAL;
> > - }
> > - return 0;
> > + else
> > + *desc_len = hba->desc_size[desc_id];
> > }
> > EXPORT_SYMBOL(ufshcd_map_desc_id_to_length);
> >
> > +static void ufshcd_update_desc_length(struct ufs_hba *hba,
> > + enum desc_idn desc_id,
> > + unsigned char desc_len)
> > +{
> > + if (hba->desc_size[desc_id] == QUERY_DESC_MAX_SIZE &&
> > + desc_id != QUERY_DESC_IDN_STRING)
> > + hba->desc_size[desc_id] = desc_len;
> > +}
> > +
> > /**
> > * ufshcd_read_desc_param - read the specified descriptor
> > parameter
> > * @hba: Pointer to adapter instance
> > @@ -3168,16 +3105,11 @@ int ufshcd_read_desc_param(struct ufs_hba
> > *hba,
> > if (desc_id >= QUERY_DESC_IDN_MAX || !param_size)
> > return -EINVAL;
> >
> > - /* Get the max length of descriptor from structure filled
> > up at probe
> > - * time.
> > - */
> > - ret = ufshcd_map_desc_id_to_length(hba, desc_id,
> > &buff_len);
> > -
> > - /* Sanity checks */
> > - if (ret || !buff_len) {
> > - dev_err(hba->dev, "%s: Failed to get full
> > descriptor length",
> > - __func__);
> > - return ret;
> > + /* 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?

you are right, I will delete this redundat code.

>
> /* 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;
> }
>
>
> > @@ -3209,6 +3141,9 @@ int ufshcd_read_desc_param(struct ufs_hba
> > *hba,
> > goto out;
> > }
> >
> > + ufshcd_update_desc_length(hba, desc_id,
> > + desc_buf[QUERY_DESC_LENGTH_OFFSET
> > ]);
> > +
> > /* Check wherher we will not copy more data, than available
> > */
> > if (is_kmalloc && param_size > buff_len)
> > param_size = buff_len;
>
> And here, we might want to update buff_len to hold the true
> descriptor size,
> Before checking the copy-back buffer.
>

yes, buff_len should be updated here. will change it.

thanks
Bean


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