[PATCH 10/26] xen-blkfront: don't disable cache flushes when they fail

[Christoph Hellwig <hch@xxxxxx>]

blkfront always had a robust negotiation protocol for detecting a write
cache.  Stop simply disabling cache flushes when they fail as that is
a grave error.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 drivers/block/xen-blkfront.c | 29 +++++++++--------------------
 1 file changed, 9 insertions(+), 20 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 9b4ec3e4908cce..9794ac2d3299d1 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -982,18 +982,6 @@ static const char *flush_info(struct blkfront_info *info)
                return "barrier or flush: disabled;";
 }
 
-static void xlvbd_flush(struct blkfront_info *info)
-{
-       blk_queue_write_cache(info->rq, info->feature_flush ? true : false,
-                             info->feature_fua ? true : false);
-       pr_info("blkfront: %s: %s %s %s %s %s %s %s\n",
-               info->gd->disk_name, flush_info(info),
-               "persistent grants:", info->feature_persistent ?
-               "enabled;" : "disabled;", "indirect descriptors:",
-               info->max_indirect_segments ? "enabled;" : "disabled;",
-               "bounce buffer:", info->bounce ? "enabled" : "disabled;");
-}
-
 static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
 {
        int major;
@@ -1162,7 +1150,15 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
        info->sector_size = sector_size;
        info->physical_sector_size = physical_sector_size;
 
-       xlvbd_flush(info);
+       blk_queue_write_cache(info->rq, info->feature_flush ? true : false,
+                             info->feature_fua ? true : false);
+
+       pr_info("blkfront: %s: %s %s %s %s %s %s %s\n",
+               info->gd->disk_name, flush_info(info),
+               "persistent grants:", info->feature_persistent ?
+               "enabled;" : "disabled;", "indirect descriptors:",
+               info->max_indirect_segments ? "enabled;" : "disabled;",
+               "bounce buffer:", info->bounce ? "enabled" : "disabled;");
 
        if (info->vdisk_info & VDISK_READONLY)
                set_disk_ro(gd, 1);
@@ -1622,13 +1618,6 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
                                       info->gd->disk_name, 
op_name(bret.operation));
                                blkif_req(req)->error = BLK_STS_NOTSUPP;
                        }
-                       if (unlikely(blkif_req(req)->error)) {
-                               if (blkif_req(req)->error == BLK_STS_NOTSUPP)
-                                       blkif_req(req)->error = BLK_STS_OK;
-                               info->feature_fua = 0;
-                               info->feature_flush = 0;
-                               xlvbd_flush(info);
-                       }
                        fallthrough;
                case BLKIF_OP_READ:
                case BLKIF_OP_WRITE:
-- 
2.43.0