Some quick comments that got cut out of the original mail.
+ +/* + * map single buffer + */ +static int bnx2i_map_single_buf(struct bnx2i_hba *hba, + struct bnx2i_cmd *cmd) +{ + struct scsi_cmnd *sc = cmd->scsi_cmd; + struct iscsi_bd *bd = cmd->bd_tbl->bd_tbl; + int byte_count; + int bd_count; + u64 addr; + + byte_count = sc->request_bufflen; + sc->SCp.dma_handle = + pci_map_single(hba->pci_dev, sc->request_buffer, + sc->request_bufflen, sc->sc_data_direction); + addr = sc->SCp.dma_handle; + + if (byte_count > MAX_BD_LENGTH) { + bd_count = bnx2i_split_bd(cmd, addr, byte_count, 0); + } else { + bd_count = 1; + bd[0].buffer_addr_lo = addr & 0xffffffff; + bd[0].buffer_addr_hi = addr >> 32; + bd[0].buffer_length = sc->request_bufflen; + bd[0].flags = ISCSI_BD_FIRST_IN_BD_CHAIN | + ISCSI_BD_LAST_IN_BD_CHAIN; + } + bd[bd_count - 1].flags |= ISCSI_BD_LAST_IN_BD_CHAIN; + + return bd_count; +}
I think you should always be getting use_sg greater than zero now, so the map single path is not needed.
+ + +/* + * map SG list + */ +static int bnx2i_map_sg(struct bnx2i_hba *hba, struct bnx2i_cmd *cmd) +{ + struct scsi_cmnd *sc = cmd->scsi_cmd; + struct iscsi_bd *bd = cmd->bd_tbl->bd_tbl; + struct scatterlist *sg; + int byte_count = 0; + int sg_frags; + int bd_count = 0; + int sg_count; + int sg_len; + u64 addr; + int i; + + sg = sc->request_buffer; + sg_count = pci_map_sg(hba->pci_dev, sg, sc->use_sg, + sc->sc_data_direction); + + for (i = 0; i < sg_count; i++) { + sg_len = sg_dma_len(sg); + addr = sg_dma_address(sg); + if (sg_len > MAX_BD_LENGTH) + sg_frags = bnx2i_split_bd(cmd, addr, sg_len, + bd_count);
If you call blk_queue_max_segment_size() in the slave_configure callout you can limit the size of the segments that the block layer builds so they are smaller than MAX_BD_LENGTH. However, I am not sure how useful that is. I think DMA-API.txt states that the mapping code is ok to merged mutliple sglists entries into one so I think that means that we can still end up with an entry that is larger than MAX_BD_LENGTH. Not sure if there is way to tell the pci/dma map_sg code to limit this too.
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