1 files changed, 24 insertions, 4 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1756001210d2..f94bc83011ed 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -378,6 +378,12 @@ struct request_queue {
 
         unsigned int            nr_sorted;
         unsigned int            in_flight[2];
+        /*
+         * Number of active block driver functions for which blk_drain_queue()
+         * must wait. Must be incremented around functions that unlock the
+         * queue_lock internally, e.g. scsi_request_fn().
+         */
+        unsigned int            request_fn_active;
 
         unsigned int            rq_timeout;
         struct timer_list       timeout;
@@ -437,7 +443,7 @@ struct request_queue {
 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
-#define QUEUE_FLAG_DEAD         5       /* queue being torn down */
+#define QUEUE_FLAG_DYING        5       /* queue being torn down */
 #define QUEUE_FLAG_BYPASS       6       /* act as dumb FIFO queue */
 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
@@ -452,6 +458,7 @@ struct request_queue {
 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
 #define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
+#define QUEUE_FLAG_DEAD        19       /* queue tear-down finished */
 
 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
@@ -521,6 +528,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 
 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
+#define blk_queue_dying(q)      test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
 #define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 #define blk_queue_bypass(q)     test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
@@ -1180,13 +1188,25 @@ static inline int queue_discard_alignment(struct request_queue *q)
 
 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
 {
-        unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
+        unsigned int alignment, granularity, offset;
 
         if (!lim->max_discard_sectors)
                 return 0;
 
-        return (lim->discard_granularity + lim->discard_alignment - alignment)
-                & (lim->discard_granularity - 1);
+        /* Why are these in bytes, not sectors? */
+        alignment = lim->discard_alignment >> 9;
+        granularity = lim->discard_granularity >> 9;
+        if (!granularity)
+                return 0;
+
+        /* Offset of the partition start in 'granularity' sectors */
+        offset = sector_div(sector, granularity);
+
+        /* And why do we do this modulus *again* in blkdev_issue_discard()? */
+        offset = (granularity + alignment - offset) % granularity;
+
+        /* Turn it back into bytes, gaah */
+        return offset << 9;
 }
 
 static inline int bdev_discard_alignment(struct block_device *bdev)