Adjust lpfc_scsi_buf allocation to account for lun_queue_depth and
error handling
Fix: Under high load and high duress, the error handler could steal some
command resources from the normal i/o path. Rework to allocate additional
resources to avoid this scneario.
Signed-off-by: James Smart <James.Smart@xxxxxxxxxx>
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -1152,24 +1152,33 @@ lpfc_slave_alloc(struct scsi_device *sde
/*
* Populate the cmds_per_lun count scsi_bufs into this host's globally
* available list of scsi buffers. Don't allocate more than the
- * HBA limit conveyed to the midlayer via the host structure. Note
- * that this list of scsi bufs exists for the lifetime of the driver.
+ * HBA limit conveyed to the midlayer via the host structure. The
+ * formula accounts for the lun_queue_depth + error handlers + 1
+ * extra. This list of scsi bufs exists for the lifetime of the driver.
*/
total = phba->total_scsi_bufs;
- num_to_alloc = LPFC_CMD_PER_LUN;
+ num_to_alloc = phba->cfg_lun_queue_depth + 2;
if (total >= phba->cfg_hba_queue_depth) {
- printk(KERN_WARNING "%s, At config limitation of "
- "%d allocated scsi_bufs\n", __FUNCTION__, total);
+ lpfc_printf_log(phba, KERN_WARNING, LOG_FCP,
+ "%d:0704 At limitation of %d preallocated "
+ "command buffers\n", phba->brd_no, total);
return 0;
} else if (total + num_to_alloc > phba->cfg_hba_queue_depth) {
+ lpfc_printf_log(phba, KERN_WARNING, LOG_FCP,
+ "%d:0705 Allocation request of %d command "
+ "buffers will exceed max of %d. Reducing "
+ "allocation request to %d.\n", phba->brd_no,
+ num_to_alloc, phba->cfg_hba_queue_depth,
+ (phba->cfg_hba_queue_depth - total));
num_to_alloc = phba->cfg_hba_queue_depth - total;
}
for (i = 0; i < num_to_alloc; i++) {
scsi_buf = lpfc_get_scsi_buf(phba);
if (!scsi_buf) {
- printk(KERN_ERR "%s, failed to allocate "
- "scsi_buf\n", __FUNCTION__);
+ lpfc_printf_log(phba, KERN_ERR, LOG_FCP,
+ "%d:0706 Failed to allocate command "
+ "buffer\n", phba->brd_no);
break;
}
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