Commit cabca0cb authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block 

* 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block:
  Fix compile/link of init/do_mounts.c with !CONFIG_BLOCK
  When stacked block devices are in-use (e.g. md or dm), the recursive calls
parents 853da002 87c1efbf

block/ll_rw_blk.c

+52 −1
Original line number Diff line number Diff line
@@ -3116,7 +3116,7 @@ static inline int should_fail_request(struct bio *bio) 
 * bi_sector for remaps as it sees fit.  So the values of these fields

 * should NOT be depended on after the call to generic_make_request.

 */

void generic_make_request(struct bio *bio)

static inline void __generic_make_request(struct bio *bio)

{

	request_queue_t *q;

	sector_t maxsector;
@@ -3215,6 +3215,57 @@ void generic_make_request(struct bio *bio) 
	} while (ret);

}



/*

 * We only want one ->make_request_fn to be active at a time,

 * else stack usage with stacked devices could be a problem.

 * So use current->bio_{list,tail} to keep a list of requests

 * submited by a make_request_fn function.

 * current->bio_tail is also used as a flag to say if

 * generic_make_request is currently active in this task or not.

 * If it is NULL, then no make_request is active.  If it is non-NULL,

 * then a make_request is active, and new requests should be added

 * at the tail

 */

void generic_make_request(struct bio *bio)

{

	if (current->bio_tail) {

		/* make_request is active */

		*(current->bio_tail) = bio;

		bio->bi_next = NULL;

		current->bio_tail = &bio->bi_next;

		return;

	}

	/* following loop may be a bit non-obvious, and so deserves some

	 * explanation.

	 * Before entering the loop, bio->bi_next is NULL (as all callers

	 * ensure that) so we have a list with a single bio.

	 * We pretend that we have just taken it off a longer list, so

	 * we assign bio_list to the next (which is NULL) and bio_tail

	 * to &bio_list, thus initialising the bio_list of new bios to be

	 * added.  __generic_make_request may indeed add some more bios

	 * through a recursive call to generic_make_request.  If it

	 * did, we find a non-NULL value in bio_list and re-enter the loop

	 * from the top.  In this case we really did just take the bio

	 * of the top of the list (no pretending) and so fixup bio_list and

	 * bio_tail or bi_next, and call into __generic_make_request again.

	 *

	 * The loop was structured like this to make only one call to

	 * __generic_make_request (which is important as it is large and

	 * inlined) and to keep the structure simple.

	 */

	BUG_ON(bio->bi_next);

	do {

		current->bio_list = bio->bi_next;

		if (bio->bi_next == NULL)

			current->bio_tail = &current->bio_list;

		else

			bio->bi_next = NULL;

		__generic_make_request(bio);

		bio = current->bio_list;

	} while (bio);

	current->bio_tail = NULL; /* deactivate */

}



EXPORT_SYMBOL(generic_make_request);



/**

include/linux/genhd.h

+5 −1
Original line number Diff line number Diff line
@@ -434,6 +434,10 @@ static inline struct block_device *bdget_disk(struct gendisk *disk, int index) 


#endif



#endif

#else /* CONFIG_BLOCK */



static inline void printk_all_partitions(void) { }



#endif /* CONFIG_BLOCK */



#endif

include/linux/sched.h

+4 −0
Original line number Diff line number Diff line
@@ -88,6 +88,7 @@ struct sched_param { 


struct exec_domain;

struct futex_pi_state;

struct bio;



/*

 * List of flags we want to share for kernel threads,
@@ -1016,6 +1017,9 @@ struct task_struct { 
/* journalling filesystem info */

	void *journal_info;



/* stacked block device info */

	struct bio *bio_list, **bio_tail;



/* VM state */

	struct reclaim_state *reclaim_state;