[SCSI] megaraid_sas: Fix the frame count calculation

When Driver sent wrong frame count to firmware.  As this particular
command is sent to drive, FW is seeing continuous chip resets and so
the command will timeout.

Signed-off-by Bo Yang<bo.yang@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index 4014225300a07c6f41c54e7705d01e79386243cf..ffd1390b155bf0eee4034c89a595d161b3033420 100644 (file)
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -488,12 +488,13 @@ megasas_make_sgl64(struct megasas_instance *instance, struct scsi_cmnd *scp,
 
  /**
  * 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 sge_count)
            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_instance *instance, struct scsi_cmnd *scp,
         * 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_instance *instance, struct scsi_cmnd *scp,
         * 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 --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 6466bdf548c2d8addce967c3b08f2fca7647d009..fbbfe2ea049f950d0c4604e71dc7a986a032c709 100644 (file)
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -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