[PATCH 2/4] scsi: megaraid_sas - Fix the frame count calculation

bo yang
2008-03-17T19:57:21Z

Driver sent the wrong frame count to firmware. This patch fixed the frame count calculation.

Signed-off-by Bo Yang<bo.yang@lsi.com>

---
drivers/scsi/megaraid/megaraid_sas.c | 31 ++++++++++++++++---------
drivers/scsi/megaraid/megaraid_sas.h | 4 +++
2 files changed, 25 insertions(+), 10 deletions(-)

diff -rupN linux-2.6.24_orig/drivers/scsi/megaraid/megaraid_sas.c linux-2.6.24_new/drivers/scsi/megaraid/megaraid_sas.c
--- linux-2.6.24_orig/drivers/scsi/megaraid/megaraid_sas.c 2008-03-17 13:51:18.000000000 -0400
+++ linux-2.6.24_new/drivers/scsi/megaraid/megaraid_sas.c 2008-03-17 13:50:39.000000000 -0400
@@ -488,12 +488,13 @@ megasas_make_sgl64(struct megasas_instan

/**
* megasas_get_frame_count - Computes the number of frames
+ * @frame_type : type of frame- io or pthru frame
* @sge_count : number of sg elements
*
* Returns the number of frames required for numnber of sge's (sge_count)
*/

-static u32 megasas_get_frame_count(u8 sge_count)
+static u32 megasas_get_frame_count(u8 sge_count, u8 frame_type)
{
int num_cnt;
int sge_bytes;
@@ -504,13 +505,22 @@ static u32 megasas_get_frame_count(u8 sg
sizeof(struct megasas_sge32);

/*
- * Main frame can contain 2 SGEs for 64-bit SGLs and
- * 3 SGEs for 32-bit SGLs
- */
- if (IS_DMA64)
- num_cnt = sge_count - 2;
- else
- num_cnt = sge_count - 3;
+ * Main frame can contain 2 SGEs for 64-bit SGLs and
+ * 3 SGEs for 32-bit SGLs for ldio &
+ * 1 SGEs for 64-bit SGLs and
+ * 2 SGEs for 32-bit SGLs for pthru frame
+ */
+ if (unlikely(frame_type == PTHRU_FRAME)) {
+ if (IS_DMA64)
+ num_cnt = sge_count - 1;
+ else
+ num_cnt = sge_count - 2;
+ } else {
+ if (IS_DMA64)
+ num_cnt = sge_count - 2;
+ else
+ num_cnt = sge_count - 3;
+ }

if(num_cnt>0){
sge_bytes = sge_sz * num_cnt;
@@ -592,7 +602,8 @@ megasas_build_dcdb(struct megasas_instan
* Compute the total number of frames this command consumes. FW uses
* this number to pull sufficient number of frames from host memory.
*/
- cmd->frame_count = megasas_get_frame_count(pthru->sge_count);
+ cmd->frame_count = megasas_get_frame_count(pthru->sge_count,
+ PTHRU_FRAME);

return cmd->frame_count;
}
@@ -709,7 +720,7 @@ megasas_build_ldio(struct megasas_instan
* Compute the total number of frames this command consumes. FW uses
* this number to pull sufficient number of frames from host memory.
*/
- cmd->frame_count = megasas_get_frame_count(ldio->sge_count);
+ cmd->frame_count = megasas_get_frame_count(ldio->sge_count, IO_FRAME);

return cmd->frame_count;
}
diff -rupN linux-2.6.24_orig/drivers/scsi/megaraid/megaraid_sas.h linux-2.6.24_new/drivers/scsi/megaraid/megaraid_sas.h
--- linux-2.6.24_orig/drivers/scsi/megaraid/megaraid_sas.h 2008-03-07 13:45:43.000000000 -0500
+++ linux-2.6.24_new/drivers/scsi/megaraid/megaraid_sas.h 2008-03-07 14:03:41.000000000 -0500
@@ -542,6 +542,10 @@ struct megasas_ctrl_info {

#define MEGASAS_FW_BUSY 1

+/* Frame Type */
+#define IO_FRAME 0
+#define PTHRU_FRAME 1
+
/*
* When SCSI mid-layer calls driver's reset routine, driver waits for
* MEGASAS_RESET_WAIT_TIME seconds for all outstanding IO to complete. Note