Commit bddd87c7e622ea681c665049027ed84cdcafcb09
Committed by
Jens Axboe
Jens Axboe
1 parent
d02f0cff1d
Exists in
master
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7 other branches
blk-core: use BIO list management functions
Now that the bio list management stuff is generic, convert generic_make_request to use bio lists instead of its own private bio list implementation. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Showing 2 changed files with 16 additions and 19 deletions Side-by-side Diff
block/blk-core.c
| ... | ... | @@ -1490,9 +1490,9 @@ |
| 1490 | 1490 | /* |
| 1491 | 1491 | * We only want one ->make_request_fn to be active at a time, |
| 1492 | 1492 | * else stack usage with stacked devices could be a problem. |
| 1493 | - * So use current->bio_{list,tail} to keep a list of requests | |
| 1493 | + * So use current->bio_list to keep a list of requests | |
| 1494 | 1494 | * submited by a make_request_fn function. |
| 1495 | - * current->bio_tail is also used as a flag to say if | |
| 1495 | + * current->bio_list is also used as a flag to say if | |
| 1496 | 1496 | * generic_make_request is currently active in this task or not. |
| 1497 | 1497 | * If it is NULL, then no make_request is active. If it is non-NULL, |
| 1498 | 1498 | * then a make_request is active, and new requests should be added |
| 1499 | 1499 | |
| ... | ... | @@ -1500,11 +1500,11 @@ |
| 1500 | 1500 | */ |
| 1501 | 1501 | void generic_make_request(struct bio *bio) |
| 1502 | 1502 | { |
| 1503 | - if (current->bio_tail) { | |
| 1503 | + struct bio_list bio_list_on_stack; | |
| 1504 | + | |
| 1505 | + if (current->bio_list) { | |
| 1504 | 1506 | /* make_request is active */ |
| 1505 | - *(current->bio_tail) = bio; | |
| 1506 | - bio->bi_next = NULL; | |
| 1507 | - current->bio_tail = &bio->bi_next; | |
| 1507 | + bio_list_add(current->bio_list, bio); | |
| 1508 | 1508 | return; |
| 1509 | 1509 | } |
| 1510 | 1510 | /* following loop may be a bit non-obvious, and so deserves some |
| 1511 | 1511 | |
| 1512 | 1512 | |
| 1513 | 1513 | |
| 1514 | 1514 | |
| 1515 | 1515 | |
| ... | ... | @@ -1512,30 +1512,27 @@ |
| 1512 | 1512 | * Before entering the loop, bio->bi_next is NULL (as all callers |
| 1513 | 1513 | * ensure that) so we have a list with a single bio. |
| 1514 | 1514 | * We pretend that we have just taken it off a longer list, so |
| 1515 | - * we assign bio_list to the next (which is NULL) and bio_tail | |
| 1516 | - * to &bio_list, thus initialising the bio_list of new bios to be | |
| 1515 | + * we assign bio_list to a pointer to the bio_list_on_stack, | |
| 1516 | + * thus initialising the bio_list of new bios to be | |
| 1517 | 1517 | * added. __generic_make_request may indeed add some more bios |
| 1518 | 1518 | * through a recursive call to generic_make_request. If it |
| 1519 | 1519 | * did, we find a non-NULL value in bio_list and re-enter the loop |
| 1520 | 1520 | * from the top. In this case we really did just take the bio |
| 1521 | - * of the top of the list (no pretending) and so fixup bio_list and | |
| 1522 | - * bio_tail or bi_next, and call into __generic_make_request again. | |
| 1521 | + * of the top of the list (no pretending) and so remove it from | |
| 1522 | + * bio_list, and call into __generic_make_request again. | |
| 1523 | 1523 | * |
| 1524 | 1524 | * The loop was structured like this to make only one call to |
| 1525 | 1525 | * __generic_make_request (which is important as it is large and |
| 1526 | 1526 | * inlined) and to keep the structure simple. |
| 1527 | 1527 | */ |
| 1528 | 1528 | BUG_ON(bio->bi_next); |
| 1529 | + bio_list_init(&bio_list_on_stack); | |
| 1530 | + current->bio_list = &bio_list_on_stack; | |
| 1529 | 1531 | do { |
| 1530 | - current->bio_list = bio->bi_next; | |
| 1531 | - if (bio->bi_next == NULL) | |
| 1532 | - current->bio_tail = ¤t->bio_list; | |
| 1533 | - else | |
| 1534 | - bio->bi_next = NULL; | |
| 1535 | 1532 | __generic_make_request(bio); |
| 1536 | - bio = current->bio_list; | |
| 1533 | + bio = bio_list_pop(current->bio_list); | |
| 1537 | 1534 | } while (bio); |
| 1538 | - current->bio_tail = NULL; /* deactivate */ | |
| 1535 | + current->bio_list = NULL; /* deactivate */ | |
| 1539 | 1536 | } |
| 1540 | 1537 | EXPORT_SYMBOL(generic_make_request); |
| 1541 | 1538 |
include/linux/sched.h
| ... | ... | @@ -97,7 +97,7 @@ |
| 97 | 97 | struct exec_domain; |
| 98 | 98 | struct futex_pi_state; |
| 99 | 99 | struct robust_list_head; |
| 100 | -struct bio; | |
| 100 | +struct bio_list; | |
| 101 | 101 | struct fs_struct; |
| 102 | 102 | struct bts_context; |
| 103 | 103 | struct perf_event_context; |
| ... | ... | @@ -1466,7 +1466,7 @@ |
| 1466 | 1466 | void *journal_info; |
| 1467 | 1467 | |
| 1468 | 1468 | /* stacked block device info */ |
| 1469 | - struct bio *bio_list, **bio_tail; | |
| 1469 | + struct bio_list *bio_list; | |
| 1470 | 1470 | |
| 1471 | 1471 | /* VM state */ |
| 1472 | 1472 | struct reclaim_state *reclaim_state; |