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;
 }