block: loop: set discard granularity and alignment for block device backed loop

[linux-2.6-microblaze.git] / drivers / block / loop.c

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 2f137d6..3d7a190 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -878,6 +878,7 @@ static void loop_config_discard(struct loop_device *lo)
        struct file *file = lo->lo_backing_file;
        struct inode *inode = file->f_mapping->host;
        struct request_queue *q = lo->lo_queue;
+       u32 granularity, max_discard_sectors;
 
        /*
         * If the backing device is a block device, mirror its zeroing
@@ -890,11 +891,10 @@ static void loop_config_discard(struct loop_device *lo)
                struct request_queue *backingq;
 
                backingq = bdev_get_queue(inode->i_bdev);
-               blk_queue_max_discard_sectors(q,
-                       backingq->limits.max_write_zeroes_sectors);
 
-               blk_queue_max_write_zeroes_sectors(q,
-                       backingq->limits.max_write_zeroes_sectors);
+               max_discard_sectors = backingq->limits.max_write_zeroes_sectors;
+               granularity = backingq->limits.discard_granularity ?:
+                       queue_physical_block_size(backingq);
 
        /*
         * We use punch hole to reclaim the free space used by the
@@ -903,23 +903,26 @@ static void loop_config_discard(struct loop_device *lo)
         * useful information.
         */
        } else if (!file->f_op->fallocate || lo->lo_encrypt_key_size) {
-               q->limits.discard_granularity = 0;
-               q->limits.discard_alignment = 0;
-               blk_queue_max_discard_sectors(q, 0);
-               blk_queue_max_write_zeroes_sectors(q, 0);
+               max_discard_sectors = 0;
+               granularity = 0;
 
        } else {
-               q->limits.discard_granularity = inode->i_sb->s_blocksize;
-               q->limits.discard_alignment = 0;
-
-               blk_queue_max_discard_sectors(q, UINT_MAX >> 9);
-               blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9);
+               max_discard_sectors = UINT_MAX >> 9;
+               granularity = inode->i_sb->s_blocksize;
        }
 
-       if (q->limits.max_write_zeroes_sectors)
+       if (max_discard_sectors) {
+               q->limits.discard_granularity = granularity;
+               blk_queue_max_discard_sectors(q, max_discard_sectors);
+               blk_queue_max_write_zeroes_sectors(q, max_discard_sectors);
                blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
-       else
+       } else {
+               q->limits.discard_granularity = 0;
+               blk_queue_max_discard_sectors(q, 0);
+               blk_queue_max_write_zeroes_sectors(q, 0);
                blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q);
+       }
+       q->limits.discard_alignment = 0;
 }
 
 static void loop_unprepare_queue(struct loop_device *lo)