From 8f9b565482c537821588444e09ff732c7d65ed6e Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Thu, 30 Jul 2015 18:28:13 -0700 Subject: target/qla2xxx: Honor max_data_sg_nents I/O transfer limit This patch adds an optional fabric driver provided SGL limit that target-core will honor as it's own internal I/O maximum transfer length limit, as exposed by EVPD=0xb0 block limits parameters. This is required for handling cases when host I/O transfer length exceeds the requested EVPD block limits maximum transfer length. The initial user of this logic is qla2xxx, so that we can avoid having to reject I/Os from some legacy FC hosts where EVPD=0xb0 parameters are not honored. When se_cmd payload length exceeds the provided limit in target_check_max_data_sg_nents() code, se_cmd->data_length + se_cmd->prot_length are reset with se_cmd->residual_count plus underflow bit for outgoing TFO response callbacks. It also checks for existing CDB level underflow + overflow and recalculates final residual_count as necessary. Note this patch currently assumes 1:1 mapping of PAGE_SIZE per struct scatterlist entry. Reported-by: Craig Watson Cc: Craig Watson Tested-by: Himanshu Madhani Cc: Roland Dreier Cc: Arun Easi Cc: Giridhar Malavali Cc: Andrew Vasquez Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Martin K. Petersen Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_spc.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'drivers/target/target_core_spc.c') diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c index a07d455e0dd5..0e0456f6a282 100644 --- a/drivers/target/target_core_spc.c +++ b/drivers/target/target_core_spc.c @@ -477,8 +477,8 @@ static sense_reason_t spc_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf) { struct se_device *dev = cmd->se_dev; - int have_tp = 0; - int opt, min; + u32 mtl = 0; + int have_tp = 0, opt, min; /* * Following spc3r22 section 6.5.3 Block Limits VPD page, when @@ -509,8 +509,15 @@ spc_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf) /* * Set MAXIMUM TRANSFER LENGTH + * + * XXX: Currently assumes single PAGE_SIZE per scatterlist for fabrics + * enforcing maximum HW scatter-gather-list entry limit */ - put_unaligned_be32(dev->dev_attrib.hw_max_sectors, &buf[8]); + if (cmd->se_tfo->max_data_sg_nents) { + mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE) / + dev->dev_attrib.block_size; + } + put_unaligned_be32(min_not_zero(mtl, dev->dev_attrib.hw_max_sectors), &buf[8]); /* * Set OPTIMAL TRANSFER LENGTH -- cgit v1.2.3