cciss: simplify scatter gather code

cciss: simplify scatter gather code.
Instead of allocating an array of pointers to a structure
containing an SGDescriptor structure, and two other elements
that aren't really used, just allocate SGDescriptor structs.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

2 files changed, 16 insertions, 35 deletions

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index eddb916d2908..adc517c1381c 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -257,7 +257,7 @@ static inline void removeQ(CommandList_struct *c)
         hlist_del_init(&c->list);
 }
 
-static void cciss_free_sg_chain_blocks(struct Cmd_sg_list **cmd_sg_list,
+static void cciss_free_sg_chain_blocks(SGDescriptor_struct **cmd_sg_list,
         int nr_cmds)
 {
         int i;
@@ -265,20 +265,17 @@ static void cciss_free_sg_chain_blocks(struct Cmd_sg_list **cmd_sg_list,
         if (!cmd_sg_list)
                 return;
         for (i = 0; i < nr_cmds; i++) {
-                if (cmd_sg_list[i]) {
-                        kfree(cmd_sg_list[i]->sgchain);
-                        kfree(cmd_sg_list[i]);
-                        cmd_sg_list[i] = NULL;
-                }
+                kfree(cmd_sg_list[i]);
+                cmd_sg_list[i] = NULL;
         }
         kfree(cmd_sg_list);
 }
 
-static struct Cmd_sg_list **cciss_allocate_sg_chain_blocks(ctlr_info_t *h,
-        int chainsize, int nr_cmds)
+static SGDescriptor_struct **cciss_allocate_sg_chain_blocks(
+        ctlr_info_t *h, int chainsize, int nr_cmds)
 {
         int j;
-        struct Cmd_sg_list **cmd_sg_list;
+        SGDescriptor_struct **cmd_sg_list;
 
         if (chainsize <= 0)
                 return NULL;
@@ -289,16 +286,10 @@ static struct Cmd_sg_list **cciss_allocate_sg_chain_blocks(ctlr_info_t *h,
 
         /* Build up chain blocks for each command */
         for (j = 0; j < nr_cmds; j++) {
-                cmd_sg_list[j] = kmalloc(sizeof(*cmd_sg_list[j]), GFP_KERNEL);
-                if (!cmd_sg_list[j]) {
-                        dev_err(&h->pdev->dev, "Cannot get memory "
-                                "for chain block.\n");
-                        goto clean;
-                }
                 /* Need a block of chainsized s/g elements. */
-                cmd_sg_list[j]->sgchain = kmalloc((chainsize *
-                        sizeof(SGDescriptor_struct)), GFP_KERNEL);
-                if (!cmd_sg_list[j]->sgchain) {
+                cmd_sg_list[j] = kmalloc((chainsize *
+                        sizeof(*cmd_sg_list[j])), GFP_KERNEL);
+                if (!cmd_sg_list[j]) {
                         dev_err(&h->pdev->dev, "Cannot get memory "
                                 "for s/g chains.\n");
                         goto clean;
@@ -1731,7 +1722,7 @@ static void cciss_softirq_done(struct request *rq)
                         pci_unmap_single(h->pdev, temp64.val,
                                                 cmd->SG[i].Len, ddir);
                         /* Point to the next block */
-                        curr_sg = h->cmd_sg_list[cmd->cmdindex]->sgchain;
+                        curr_sg = h->cmd_sg_list[cmd->cmdindex];
                         sg_index = 0;
                 }
                 temp64.val32.lower = curr_sg[sg_index].Addr.lower;
@@ -3206,7 +3197,7 @@ static void do_cciss_request(struct request_queue *q)
                         curr_sg[sg_index].Ext = CCISS_SG_CHAIN;
 
                         /* Point to next chain block. */
-                        curr_sg = h->cmd_sg_list[c->cmdindex]->sgchain;
+                        curr_sg = h->cmd_sg_list[c->cmdindex];
                         sg_index = 0;
                         chained = 1;
                 }
@@ -3223,6 +3214,7 @@ static void do_cciss_request(struct request_queue *q)
 
         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;
@@ -3231,16 +3223,11 @@ static void do_cciss_request(struct request_queue *q)
                  * block with address of next chain block.
                  */
                 temp64.val = pci_map_single(h->pdev,
-                                        h->cmd_sg_list[c->cmdindex]->sgchain,
-                                        len, dir);
-
-                h->cmd_sg_list[c->cmdindex]->sg_chain_dma = temp64.val;
+                                        h->cmd_sg_list[c->cmdindex], len, dir);
+                dma_addr = temp64.val;
                 curr_sg[sg_index].Addr.lower = temp64.val32.lower;
                 curr_sg[sg_index].Addr.upper = temp64.val32.upper;
-
-                pci_dma_sync_single_for_device(h->pdev,
-                                h->cmd_sg_list[c->cmdindex]->sg_chain_dma,
-                                len, dir);
+                pci_dma_sync_single_for_device(h->pdev, dma_addr, len, dir);
         }
 
         /* track how many SG entries we are using */
diff --git a/drivers/block/cciss.h b/drivers/block/cciss.h
index 2b07bdacbd12..ac454fdd4d30 100644
--- a/drivers/block/cciss.h
+++ b/drivers/block/cciss.h
@@ -55,12 +55,6 @@ typedef struct _drive_info_struct
         char device_initialized;     /* indicates whether dev is initialized */
 } drive_info_struct;
 
-struct Cmd_sg_list {
-        SGDescriptor_struct     *sgchain;
-        dma_addr_t              sg_chain_dma;
-        int                     chain_block_size;
-};
-
 struct ctlr_info
 {
         int     ctlr;
@@ -89,7 +83,7 @@ struct ctlr_info
         int     maxsgentries;
         int     chainsize;
         int     max_cmd_sgentries;
-        struct Cmd_sg_list **cmd_sg_list;
+        SGDescriptor_struct **cmd_sg_list;
 
 #       define DOORBELL_INT     0
 #       define PERF_MODE_INT    1