From 84badfab0d914e2c9e96bdc3f418d7f494bfb0bb Mon Sep 17 00:00:00 2001 From: Sumit Saxena Date: Fri, 8 May 2020 14:08:35 +0530 Subject: [PATCH] scsi: megaraid_sas: Remove IO buffer hole detection logic As blk_queue_virt_boundary() API in slave_configure ensures that no IOs will come with holes/gaps. Hence, code logic to detect the holes/gaps in IO buffer is not required. Link: https://lore.kernel.org/r/20200508083838.22778-3-chandrakanth.patil@broadcom.com Signed-off-by: Sumit Saxena Signed-off-by: Chandrakanth Patil Signed-off-by: Martin K. Petersen --- drivers/scsi/megaraid/megaraid_sas_fusion.c | 58 ----------------------------- 1 file changed, 58 deletions(-) diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c b/drivers/scsi/megaraid/megaraid_sas_fusion.c index e0f923b..87f91a38 100644 --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c @@ -2070,7 +2070,6 @@ static bool megasas_is_prp_possible(struct megasas_instance *instance, struct scsi_cmnd *scmd, int sge_count) { - int i; u32 data_length = 0; struct scatterlist *sg_scmd; bool build_prp = false; @@ -2099,63 +2098,6 @@ megasas_is_prp_possible(struct megasas_instance *instance, build_prp = true; } -/* - * Below code detects gaps/holes in IO data buffers. - * What does holes/gaps mean? - * Any SGE except first one in a SGL starts at non NVME page size - * aligned address OR Any SGE except last one in a SGL ends at - * non NVME page size boundary. - * - * Driver has already informed block layer by setting boundary rules for - * bio merging done at NVME page size boundary calling kernel API - * blk_queue_virt_boundary inside slave_config. - * Still there is possibility of IO coming with holes to driver because of - * IO merging done by IO scheduler. - * - * With SCSI BLK MQ enabled, there will be no IO with holes as there is no - * IO scheduling so no IO merging. - * - * With SCSI BLK MQ disabled, IO scheduler may attempt to merge IOs and - * then sending IOs with holes. - * - * Though driver can request block layer to disable IO merging by calling- - * blk_queue_flag_set(QUEUE_FLAG_NOMERGES, sdev->request_queue) but - * user may tune sysfs parameter- nomerges again to 0 or 1. - * - * If in future IO scheduling is enabled with SCSI BLK MQ, - * this algorithm to detect holes will be required in driver - * for SCSI BLK MQ enabled case as well. - * - * - */ - scsi_for_each_sg(scmd, sg_scmd, sge_count, i) { - if ((i != 0) && (i != (sge_count - 1))) { - if (mega_mod64(sg_dma_len(sg_scmd), mr_nvme_pg_size) || - mega_mod64(sg_dma_address(sg_scmd), - mr_nvme_pg_size)) { - build_prp = false; - break; - } - } - - if ((sge_count > 1) && (i == 0)) { - if ((mega_mod64((sg_dma_address(sg_scmd) + - sg_dma_len(sg_scmd)), - mr_nvme_pg_size))) { - build_prp = false; - break; - } - } - - if ((sge_count > 1) && (i == (sge_count - 1))) { - if (mega_mod64(sg_dma_address(sg_scmd), - mr_nvme_pg_size)) { - build_prp = false; - break; - } - } - } - return build_prp; } -- 2.7.4