staging/lustre/llite: to configure max_cached_mb correctly

If there exists MGS conf_param to reduce the memory cache
max_cached_mb it will fail because dt_exp is not initialized
yet.

It should just go ahead and configure it because certainly it
have enough free LRU slot to deduct ccc_lru_left.

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-on: http://review.whamcloud.com/11783
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3676
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/llite/lproc_llite.c b/drivers/staging/lustre/lustre/llite/lproc_llite.c
index e6a909e..aaa13bd 100644 (file)
--- a/drivers/staging/lustre/lustre/llite/lproc_llite.c
+++ b/drivers/staging/lustre/lustre/llite/lproc_llite.c
@@ -399,9 +399,6 @@ static ssize_t ll_max_cached_mb_seq_write(struct file *file,
                return -ERANGE;
        }
 
-       if (sbi->ll_dt_exp == NULL)
-               return -ENODEV;
-
        spin_lock(&sbi->ll_lock);
        diff = pages_number - cache->ccc_lru_max;
        spin_unlock(&sbi->ll_lock);
@@ -437,6 +434,11 @@ static ssize_t ll_max_cached_mb_seq_write(struct file *file,
                if (diff <= 0)
                        break;
 
+               if (sbi->ll_dt_exp == NULL) { /* being initialized */
+                       rc = -ENODEV;
+                       break;
+               }
+
                /* difficult - have to ask OSCs to drop LRU slots. */
                tmp = diff << 1;
                rc = obd_set_info_async(NULL, sbi->ll_dt_exp,