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From: Stephen M. Cameron on 26 Feb 2010 17:00
From: Stephen M. Cameron <scameron(a)beardog.cce.hp.com>

cciss: factor out scatter gather chain block mapping code
Rationale is I want to use this code from the scsi half of the
driver.

Signed-off-by: Stephen M. Cameron <scameron(a)beardog.cce.hp.com>
---
drivers/block/cciss.c | 63 ++++++++++++++++++++++++++-----------------------
1 files changed, 34 insertions(+), 29 deletions(-)

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index c0d794c..9e3af30 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -301,6 +301,35 @@ clean:
return NULL;
}

+static void cciss_unmap_sg_chain_block(ctlr_info_t *h, CommandList_struct *c)
+{
+ SGDescriptor_struct *chain_sg;
+ u64bit temp64;
+
+ if (c->Header.SGTotal <= h->max_cmd_sgentries)
+ return;
+
+ chain_sg = &c->SG[h->max_cmd_sgentries - 1];
+ temp64.val32.lower = chain_sg->Addr.lower;
+ temp64.val32.upper = chain_sg->Addr.upper;
+ pci_unmap_single(h->pdev, temp64.val, chain_sg->Len, PCI_DMA_TODEVICE);
+}
+
+static void cciss_map_sg_chain_block(ctlr_info_t *h, CommandList_struct *c,
+ SGDescriptor_struct *chain_block, int len)
+{
+ SGDescriptor_struct *chain_sg;
+ u64bit temp64;
+
+ chain_sg = &c->SG[h->max_cmd_sgentries - 1];
+ chain_sg->Ext = CCISS_SG_CHAIN;
+ chain_sg->Len = len;
+ temp64.val = pci_map_single(h->pdev, chain_block, len,
+ PCI_DMA_TODEVICE);
+ chain_sg->Addr.lower = temp64.val32.lower;
+ chain_sg->Addr.upper = temp64.val32.upper;
+}
+
#include "cciss_scsi.c" /* For SCSI tape support */

static const char *raid_label[] = { "0", "4", "1(1+0)", "5", "5+1", "ADG",
@@ -1715,10 +1744,7 @@ static void cciss_softirq_done(struct request *rq)
/* unmap the DMA mapping for all the scatter gather elements */
for (i = 0; i < cmd->Header.SGList; i++) {
if (curr_sg[sg_index].Ext == CCISS_SG_CHAIN) {
- temp64.val32.lower = cmd->SG[i].Addr.lower;
- temp64.val32.upper = cmd->SG[i].Addr.upper;
- pci_unmap_single(h->pdev, temp64.val,
- cmd->SG[i].Len, PCI_DMA_TODEVICE);
+ cciss_unmap_sg_chain_block(h, cmd);
/* Point to the next block */
curr_sg = h->cmd_sg_list[cmd->cmdindex];
sg_index = 0;
@@ -3122,7 +3148,6 @@ static void do_cciss_request(struct request_queue *q)
SGDescriptor_struct *curr_sg;
drive_info_struct *drv;
int i, dir;
- int nseg = 0;
int sg_index = 0;
int chained = 0;

@@ -3189,11 +3214,6 @@ static void do_cciss_request(struct request_queue *q)
for (i = 0; i < seg; i++) {
if (((sg_index+1) == (h->max_cmd_sgentries)) &&
!chained && ((seg - i) > 1)) {
- nseg = seg - i;
- curr_sg[sg_index].Len = (nseg) *
- sizeof(SGDescriptor_struct);
- curr_sg[sg_index].Ext = CCISS_SG_CHAIN;
-
/* Point to next chain block. */
curr_sg = h->cmd_sg_list[c->cmdindex];
sg_index = 0;
@@ -3206,27 +3226,12 @@ static void do_cciss_request(struct request_queue *q)
curr_sg[sg_index].Addr.lower = temp64.val32.lower;
curr_sg[sg_index].Addr.upper = temp64.val32.upper;
curr_sg[sg_index].Ext = 0; /* we are not chaining */
-
++sg_index;
}
-
- if (chained) {
- int len;
- dma_addr_t dma_addr;
- curr_sg = c->SG;
- sg_index = h->max_cmd_sgentries - 1;
- len = curr_sg[sg_index].Len;
- /* Setup pointer to next chain block.
- * Fill out last element in current chain
- * block with address of next chain block.
- */
- temp64.val = pci_map_single(h->pdev,
- h->cmd_sg_list[c->cmdindex], len,
- PCI_DMA_TODEVICE);
- dma_addr = temp64.val;
- curr_sg[sg_index].Addr.lower = temp64.val32.lower;
- curr_sg[sg_index].Addr.upper = temp64.val32.upper;
- }
+ if (chained)
+ cciss_map_sg_chain_block(h, c, h->cmd_sg_list[c->cmdindex],
+ (seg - (h->max_cmd_sgentries - 1)) *
+ sizeof(SGDescriptor_struct));

/* track how many SG entries we are using */
if (seg > h->maxSG)

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Next: [PATCH 2/9] cciss: detect bad alignment of scsi commands at build time