Hi Hannes,
static struct pqi_io_request *pqi_alloc_io_request(
- struct pqi_ctrl_info *ctrl_info)
+ struct pqi_ctrl_info *ctrl_info, struct scsi_cmnd *scmd)
{
struct pqi_io_request *io_request;
+ unsigned int limit = PQI_RESERVED_IO_SLOTS;
u16 i = ctrl_info->next_io_request_slot; /* benignly racy */
- while (1) {
+ if (scmd) {
+ u32 blk_tag = blk_mq_unique_tag(scmd->request);
+
+ i = blk_mq_unique_tag_to_tag(blk_tag) + limit;
io_request = &ctrl_info->io_request_pool[i];
This looks ok
- if (atomic_inc_return(&io_request->refcount) == 1)
- break;
- atomic_dec(&io_request->refcount);
- i = (i + 1) % ctrl_info->max_io_slots;
+ if (WARN_ON(atomic_inc_return(&io_request->refcount) > 1)) {
+ atomic_dec(&io_request->refcount);
+ return NULL;
+ }
+ } else {
+ while (1) {
+ io_request = &ctrl_info->io_request_pool[i];
+ if (atomic_inc_return(&io_request->refcount) == 1)
+ break;
+ atomic_dec(&io_request->refcount);
+ i = (i + 1) % limit;
To me, the range we use here looks incorrect. I would assume we should
restrict range to [max_io_slots - PQI_RESERVED_IO_SLOTS, max_io_slots).
But then your reserved commands support would solve that.
+ }
}
Thanks,
John
