block: add request update interface

[linux-2.6-omap-h63xx.git] / block / blk-core.c

diff --git a/block/blk-core.c b/block/blk-core.c
index 37fba001bdcf6b9a0174fdf40c6c8eb3eeda7fac..527d43e982bb0d1b4a4310a5550714364e7d501c 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1806,6 +1806,22 @@ void end_request(struct request *req, int uptodate)
 }
 EXPORT_SYMBOL(end_request);
 
+static int end_that_request_data(struct request *rq, int error,
+                                unsigned int nr_bytes, unsigned int bidi_bytes)
+{
+       if (rq->bio) {
+               if (__end_that_request_first(rq, error, nr_bytes))
+                       return 1;
+
+               /* Bidi request must be completed as a whole */
+               if (blk_bidi_rq(rq) &&
+                   __end_that_request_first(rq->next_rq, error, bidi_bytes))
+                       return 1;
+       }
+
+       return 0;
+}
+
 /**
  * blk_end_io - Generic end_io function to complete a request.
  * @rq:           the request being processed
@@ -1832,15 +1848,8 @@ static int blk_end_io(struct request *rq, int error, unsigned int nr_bytes,
        struct request_queue *q = rq->q;
        unsigned long flags = 0UL;
 
-       if (rq->bio) {
-               if (__end_that_request_first(rq, error, nr_bytes))
-                       return 1;
-
-               /* Bidi request must be completed as a whole */
-               if (blk_bidi_rq(rq) &&
-                   __end_that_request_first(rq->next_rq, error, bidi_bytes))
-                       return 1;
-       }
+       if (end_that_request_data(rq, error, nr_bytes, bidi_bytes))
+               return 1;
 
        /* Special feature for tricky drivers */
        if (drv_callback && drv_callback(rq))
@@ -1922,6 +1931,36 @@ int blk_end_bidi_request(struct request *rq, int error, unsigned int nr_bytes,
 }
 EXPORT_SYMBOL_GPL(blk_end_bidi_request);
 
+/**
+ * blk_update_request - Special helper function for request stacking drivers
+ * @rq:           the request being processed
+ * @error:        %0 for success, < %0 for error
+ * @nr_bytes:     number of bytes to complete @rq
+ *
+ * Description:
+ *     Ends I/O on a number of bytes attached to @rq, but doesn't complete
+ *     the request structure even if @rq doesn't have leftover.
+ *     If @rq has leftover, sets it up for the next range of segments.
+ *
+ *     This special helper function is only for request stacking drivers
+ *     (e.g. request-based dm) so that they can handle partial completion.
+ *     Actual device drivers should use blk_end_request instead.
+ */
+void blk_update_request(struct request *rq, int error, unsigned int nr_bytes)
+{
+       if (!end_that_request_data(rq, error, nr_bytes, 0)) {
+               /*
+                * These members are not updated in end_that_request_data()
+                * when all bios are completed.
+                * Update them so that the request stacking driver can find
+                * how many bytes remain in the request later.
+                */
+               rq->nr_sectors = rq->hard_nr_sectors = 0;
+               rq->current_nr_sectors = rq->hard_cur_sectors = 0;
+       }
+}
+EXPORT_SYMBOL_GPL(blk_update_request);
+
 /**
  * blk_end_request_callback - Special helper function for tricky drivers
  * @rq:           the request being processed