From c7ee65b3841f4e3e40d154ebcb80acb79b261c1c Mon Sep 17 00:00:00 2001 From: Webb Scales Date: Fri, 23 Jan 2015 16:42:17 -0600 Subject: [PATCH] hpsa: refactor hpsa_find_board_params() to encapsulate legacy test Encapsulate the conditional predicate which tests for legacy controllers in a separate function and rework the code comments. Reviewed-by: Scott Teel Signed-off-by: Webb Scales Signed-off-by: Don Brace Signed-off-by: Christoph Hellwig --- drivers/scsi/hpsa.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c index ec2503a720c6..08d96a9d9d0a 100644 --- a/drivers/scsi/hpsa.c +++ b/drivers/scsi/hpsa.c @@ -3107,7 +3107,8 @@ static void hpsa_update_scsi_devices(struct ctlr_info *h, int hostno) kfree(logdev_list); } -/* hpsa_scatter_gather takes a struct scsi_cmnd, (cmd), and does the pci +/* + * hpsa_scatter_gather takes a struct scsi_cmnd, (cmd), and does the pci * dma mapping and fills in the scatter gather entries of the * hpsa command, cp. */ @@ -3165,7 +3166,7 @@ static int hpsa_scatter_gather(struct ctlr_info *h, sglist_finished: cp->Header.SGList = (u8) use_sg; /* no. SGs contig in this cmd */ - cp->Header.SGTotal = cpu_to_le16(use_sg); /* total sgs in this cmd list */ + cp->Header.SGTotal = cpu_to_le16(use_sg); /* total sgs in cmd list */ return 0; } @@ -6162,6 +6163,15 @@ static void hpsa_get_max_perf_mode_cmds(struct ctlr_info *h) } } +/* If the controller reports that the total max sg entries is greater than 512, + * then we know that chained SG blocks work. (Original smart arrays did not + * support chained SG blocks and would return zero for max sg entries.) + */ +static int hpsa_supports_chained_sg_blocks(struct ctlr_info *h) +{ + return h->maxsgentries > 512; +} + /* Interrogate the hardware for some limits: * max commands, max SG elements without chaining, and with chaining, * SG chain block size, etc. @@ -6172,18 +6182,20 @@ static void hpsa_find_board_params(struct ctlr_info *h) h->nr_cmds = h->max_commands - 4; /* Allow room for some ioctls */ h->maxsgentries = readl(&(h->cfgtable->MaxScatterGatherElements)); h->fw_support = readl(&(h->cfgtable->misc_fw_support)); - /* - * Limit in-command s/g elements to 32 save dma'able memory. - * Howvever spec says if 0, use 31 - */ - h->max_cmd_sg_entries = 31; - if (h->maxsgentries > 512) { + if (hpsa_supports_chained_sg_blocks(h)) { + /* Limit in-command s/g elements to 32 save dma'able memory. */ h->max_cmd_sg_entries = 32; h->chainsize = h->maxsgentries - h->max_cmd_sg_entries; h->maxsgentries--; /* save one for chain pointer */ } else { - h->chainsize = 0; + /* + * Original smart arrays supported at most 31 s/g entries + * embedded inline in the command (trying to use more + * would lock up the controller) + */ + h->max_cmd_sg_entries = 31; h->maxsgentries = 31; /* default to traditional values */ + h->chainsize = 0; } /* Find out what task management functions are supported and cache */