[PATCH 09/14] sd: factor out a sd_discard_mode helper

[Christoph Hellwig <hch@xxxxxx>]

Split the logic to pick the right discard mode into a little helper
to prepare for further changes.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
---
 drivers/scsi/sd.c | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 0dbc6eb7a7cac3..39eddfac09ef8f 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3201,6 +3201,25 @@ static void sd_read_app_tag_own(struct scsi_disk *sdkp, 
unsigned char *buffer)
        return;
 }
 
+static unsigned int sd_discard_mode(struct scsi_disk *sdkp)
+{
+       if (!sdkp->lbpvpd) {
+               /* LBP VPD page not provided */
+               if (sdkp->max_unmap_blocks)
+                       return SD_LBP_UNMAP;
+               return SD_LBP_WS16;
+       }
+
+       /* LBP VPD page tells us what to use */
+       if (sdkp->lbpu && sdkp->max_unmap_blocks)
+               return SD_LBP_UNMAP;
+       if (sdkp->lbpws)
+               return SD_LBP_WS16;
+       if (sdkp->lbpws10)
+               return SD_LBP_WS10;
+       return SD_LBP_DISABLE;
+}
+
 /**
  * sd_read_block_limits - Query disk device for preferred I/O sizes.
  * @sdkp: disk to query
@@ -3239,23 +3258,7 @@ static void sd_read_block_limits(struct scsi_disk *sdkp)
                        sdkp->unmap_alignment =
                                get_unaligned_be32(&vpd->data[32]) & ~(1 << 31);
 
-               if (!sdkp->lbpvpd) { /* LBP VPD page not provided */
-
-                       if (sdkp->max_unmap_blocks)
-                               sd_config_discard(sdkp, SD_LBP_UNMAP);
-                       else
-                               sd_config_discard(sdkp, SD_LBP_WS16);
-
-               } else {        /* LBP VPD page tells us what to use */
-                       if (sdkp->lbpu && sdkp->max_unmap_blocks)
-                               sd_config_discard(sdkp, SD_LBP_UNMAP);
-                       else if (sdkp->lbpws)
-                               sd_config_discard(sdkp, SD_LBP_WS16);
-                       else if (sdkp->lbpws10)
-                               sd_config_discard(sdkp, SD_LBP_WS10);
-                       else
-                               sd_config_discard(sdkp, SD_LBP_DISABLE);
-               }
+               sd_config_discard(sdkp, sd_discard_mode(sdkp));
        }
 
  out:
-- 
2.43.0