1 files changed, 47 insertions, 25 deletions

diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index 38733b6009a4..e177fc5c5dd0 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -495,6 +495,46 @@ megasas_make_sgl64(struct megasas_instance *instance, struct scsi_cmnd *scp,
 	return sge_count;
 }
 
+ /**
+ * megasas_get_frame_count - Computes the number of frames
+ * @sge_count		: number of sg elements
+ *
+ * Returns the number of frames required for numnber of sge's (sge_count)
+ */
+
+u32 megasas_get_frame_count(u8 sge_count)
+{
+	int num_cnt;
+	int sge_bytes;
+	u32 sge_sz;
+	u32 frame_count=0;
+
+	sge_sz = (IS_DMA64) ? sizeof(struct megasas_sge64) :
+	    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;
+
+	if(num_cnt>0){
+		sge_bytes = sge_sz * num_cnt;
+
+		frame_count = (sge_bytes / MEGAMFI_FRAME_SIZE) +
+		    ((sge_bytes % MEGAMFI_FRAME_SIZE) ? 1 : 0) ;
+	}
+	/* Main frame */
+	frame_count +=1;
+
+	if (frame_count > 7)
+		frame_count = 8;
+	return frame_count;
+}
+
 /**
  * megasas_build_dcdb -	Prepares a direct cdb (DCDB) command
  * @instance:		Adapter soft state
@@ -508,8 +548,6 @@ static int
 megasas_build_dcdb(struct megasas_instance *instance, struct scsi_cmnd *scp,
 		   struct megasas_cmd *cmd)
 {
-	u32 sge_sz;
-	int sge_bytes;
 	u32 is_logical;
 	u32 device_id;
 	u16 flags = 0;
@@ -544,9 +582,6 @@ megasas_build_dcdb(struct megasas_instance *instance, struct scsi_cmnd *scp,
 	/*
 	 * Construct SGL
 	 */
-	sge_sz = (IS_DMA64) ? sizeof(struct megasas_sge64) :
-	    sizeof(struct megasas_sge32);
-
 	if (IS_DMA64) {
 		pthru->flags |= MFI_FRAME_SGL64;
 		pthru->sge_count = megasas_make_sgl64(instance, scp,
@@ -562,17 +597,11 @@ megasas_build_dcdb(struct megasas_instance *instance, struct scsi_cmnd *scp,
 	pthru->sense_buf_phys_addr_hi = 0;
 	pthru->sense_buf_phys_addr_lo = cmd->sense_phys_addr;
 
-	sge_bytes = sge_sz * pthru->sge_count;
-
 	/*
 	 * 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 = (sge_bytes / MEGAMFI_FRAME_SIZE) +
-	    ((sge_bytes % MEGAMFI_FRAME_SIZE) ? 1 : 0) + 1;
-
-	if (cmd->frame_count > 7)
-		cmd->frame_count = 8;
+	cmd->frame_count = megasas_get_frame_count(pthru->sge_count);
 
 	return cmd->frame_count;
 }
@@ -589,8 +618,6 @@ static int
 megasas_build_ldio(struct megasas_instance *instance, struct scsi_cmnd *scp,
 		   struct megasas_cmd *cmd)
 {
-	u32 sge_sz;
-	int sge_bytes;
 	u32 device_id;
 	u8 sc = scp->cmnd[0];
 	u16 flags = 0;
@@ -605,7 +632,7 @@ megasas_build_ldio(struct megasas_instance *instance, struct scsi_cmnd *scp,
 		flags = MFI_FRAME_DIR_READ;
 
 	/*
-	 * Preare the Logical IO frame: 2nd bit is zero for all read cmds
+	 * Prepare the Logical IO frame: 2nd bit is zero for all read cmds
 	 */
 	ldio->cmd = (sc & 0x02) ? MFI_CMD_LD_WRITE : MFI_CMD_LD_READ;
 	ldio->cmd_status = 0x0;
@@ -674,9 +701,6 @@ megasas_build_ldio(struct megasas_instance *instance, struct scsi_cmnd *scp,
 	/*
 	 * Construct SGL
 	 */
-	sge_sz = (IS_DMA64) ? sizeof(struct megasas_sge64) :
-	    sizeof(struct megasas_sge32);
-
 	if (IS_DMA64) {
 		ldio->flags |= MFI_FRAME_SGL64;
 		ldio->sge_count = megasas_make_sgl64(instance, scp, &ldio->sgl);
@@ -690,13 +714,11 @@ megasas_build_ldio(struct megasas_instance *instance, struct scsi_cmnd *scp,
 	ldio->sense_buf_phys_addr_hi = 0;
 	ldio->sense_buf_phys_addr_lo = cmd->sense_phys_addr;
 
-	sge_bytes = sge_sz * ldio->sge_count;
-
-	cmd->frame_count = (sge_bytes / MEGAMFI_FRAME_SIZE) +
-	    ((sge_bytes % MEGAMFI_FRAME_SIZE) ? 1 : 0) + 1;
-
-	if (cmd->frame_count > 7)
-		cmd->frame_count = 8;
+	/*
+	 * 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);
 
 	return cmd->frame_count;
 }