Reenabled linux-xen and xen-image build

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.25 / patches.fixes / block-use-bio_has_data

From 0f96bb8e2923065d58d89c5c82c9f37ad1f18404 Mon Sep 17 00:00:00 2001
From: Hannes Reinecke <hare@suse.de>
Date: Thu, 23 Oct 2008 13:42:06 +0200
Subject: [PATCH] Implement bio_has_data()

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 block/blk-core.c       |   21 +++++++--------------
 include/linux/bio.h    |   14 +++++++++++---
 include/linux/blkdev.h |    2 +-
 mm/bounce.c            |    2 +-
 4 files changed, 20 insertions(+), 19 deletions(-)

--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -624,10 +624,6 @@ blk_alloc_request(struct request_queue *
 
 	blk_rq_init(q, rq);
 
-	/*
-	 * first three bits are identical in rq->cmd_flags and bio->bi_rw,
-	 * see bio.h and blkdev.h
-	 */
 	rq->cmd_flags = rw | REQ_ALLOCED;
 
 	if (priv) {
@@ -1490,10 +1486,7 @@ void submit_bio(int rw, struct bio *bio)
 	 * If it's a regular read/write or a barrier with data attached,
 	 * go through the normal accounting stuff before submission.
 	 */
-	if (!bio_empty_barrier(bio)) {
-
-		BIO_BUG_ON(!bio->bi_size);
-		BIO_BUG_ON(!bio->bi_io_vec);
+	if (bio_has_data(bio)) {
 
 		if (rw & WRITE) {
 			count_vm_events(PGPGOUT, count);
@@ -1888,7 +1881,7 @@ static int blk_end_io(struct request *rq
 	struct request_queue *q = rq->q;
 	unsigned long flags = 0UL;
 
-	if (blk_fs_request(rq) || blk_pc_request(rq)) {
+	if (bio_has_data(rq->bio)) {
 		if (__end_that_request_first(rq, error, nr_bytes))
 			return 1;
 
@@ -1946,10 +1939,9 @@ EXPORT_SYMBOL_GPL(blk_end_request);
  **/
 int __blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
 {
-	if (blk_fs_request(rq) || blk_pc_request(rq)) {
-		if (__end_that_request_first(rq, error, nr_bytes))
-			return 1;
-	}
+	if (bio_has_data(rq->bio) &&
+	    __end_that_request_first(rq, error, nr_bytes))
+		return 1;
 
 	add_disk_randomness(rq->rq_disk);
 
@@ -2016,7 +2008,8 @@ EXPORT_SYMBOL_GPL(blk_end_request_callba
 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
 		     struct bio *bio)
 {
-	/* first two bits are identical in rq->cmd_flags and bio->bi_rw */
+	/* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw, and
+	   we want BIO_RW_AHEAD (bit 1) to imply REQ_FAILFAST (bit 1). */
 	rq->cmd_flags |= (bio->bi_rw & 3);
 
 	rq->nr_phys_segments = bio_phys_segments(q, bio);
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -157,8 +157,8 @@ struct bio {
  * bit 3 -- fail fast, don't want low level driver retries
  * bit 4 -- synchronous I/O hint: the block layer will unplug immediately
  */
-#define BIO_RW		0
-#define BIO_RW_AHEAD	1
+#define BIO_RW		0	/* Must match RW in req flags (blkdev.h) */
+#define BIO_RW_AHEAD	1	/* Must match FAILFAST in req flags */
 #define BIO_RW_BARRIER	2
 #define BIO_RW_FAILFAST	3
 #define BIO_RW_SYNC	4
@@ -192,7 +192,7 @@ struct bio {
 #define bio_failfast(bio)	((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
 #define bio_rw_ahead(bio)	((bio)->bi_rw & (1 << BIO_RW_AHEAD))
 #define bio_rw_meta(bio)	((bio)->bi_rw & (1 << BIO_RW_META))
-#define bio_empty_barrier(bio)	(bio_barrier(bio) && !(bio)->bi_size)
+#define bio_empty_barrier(bio)	(bio_barrier(bio) && !bio_has_data(bio))
 
 static inline unsigned int bio_cur_sectors(struct bio *bio)
 {
@@ -452,6 +452,14 @@ static inline char *__bio_kmap_irq(struc
 	__bio_kmap_irq((bio), (bio)->bi_idx, (flags))
 #define bio_kunmap_irq(buf,flags)	__bio_kunmap_irq(buf, flags)
 
+/*
+ * Check whether this bio carries any data or not. A NULL bio is allowed.
+ */
+static inline int bio_has_data(struct bio *bio)
+{
+	return bio && bio->bi_io_vec != NULL;
+}
+
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 
 #define bip_vec_idx(bip, idx)	(&(bip->bip_vec[(idx)]))
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -84,7 +84,7 @@ enum {
 };
 
 /*
- * request type modified bits. first three bits match BIO_RW* bits, important
+ * request type modified bits. first two bits match BIO_RW* bits, important
  */
 enum rq_flag_bits {
 	__REQ_RW,		/* not set, read. set, write */
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -267,7 +267,7 @@ void blk_queue_bounce(struct request_que
 	/*
 	 * Data-less bio, nothing to bounce
 	 */
-	if (bio_empty_barrier(*bio_orig))
+	if (!bio_has_data(*bio_orig))
 		return;
 
 	/*