On 02-May-19 21:14, Jason Gunthorpe wrote:
> On Wed, May 01, 2019 at 01:48:22PM +0300, Gal Pressman wrote:
>
>> +/* create a page buffer list from a mapped user memory region */
>> +static int pbl_create(struct efa_dev *dev,
>> + struct pbl_context *pbl,
>> + struct ib_umem *umem,
>> + int hp_cnt,
>> + u8 hp_shift)
>> +{
>> + int err;
>> +
>> + pbl->pbl_buf_size_in_bytes = hp_cnt * EFA_CHUNK_PAYLOAD_PTR_SIZE;
>> + pbl->pbl_buf = kzalloc(pbl->pbl_buf_size_in_bytes,
>> + GFP_KERNEL | __GFP_NOWARN);
>> + if (pbl->pbl_buf) {
>> + pbl->physically_continuous = 1;
>> + err = umem_to_page_list(dev, umem, pbl->pbl_buf, hp_cnt,
>> + hp_shift);
>> + if (err)
>> + goto err_continuous;
>> + err = pbl_continuous_initialize(dev, pbl);
>> + if (err)
>> + goto err_continuous;
>> + } else {
>> + pbl->physically_continuous = 0;
>> + pbl->pbl_buf = vzalloc(pbl->pbl_buf_size_in_bytes);
>> + if (!pbl->pbl_buf)
>> + return -ENOMEM;
>
> This way to fallback seems ugly, I think you should just call kvzalloc
> and check for continuity during the umem_to_page_list
I've considered using kvzalloc, but it doesn't really fit this use case.
The pbl buffer is not related to the umem continuity, it's a buffer which
describes the MR pages in case the number of pages exceeds the inline size.
In order to use the device "continuous" MR registration mode, we need the pbl
buffer to be physically continuous. Otherwise, the indirect registration mode
should be used, regardless of the umem continuity.
