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-rw-r--r--block/blk-core.c31
-rw-r--r--include/linux/sched.h4
2 files changed, 16 insertions, 19 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 718897e6d37f..44b6d691728d 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1490,9 +1490,9 @@ end_io:
1490/* 1490/*
1491 * We only want one ->make_request_fn to be active at a time, 1491 * We only want one ->make_request_fn to be active at a time,
1492 * else stack usage with stacked devices could be a problem. 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 * submited by a make_request_fn function. 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 * generic_make_request is currently active in this task or not. 1496 * generic_make_request is currently active in this task or not.
1497 * If it is NULL, then no make_request is active. If it is non-NULL, 1497 * If it is NULL, then no make_request is active. If it is non-NULL,
1498 * then a make_request is active, and new requests should be added 1498 * then a make_request is active, and new requests should be added
@@ -1500,11 +1500,11 @@ end_io:
1500 */ 1500 */
1501void generic_make_request(struct bio *bio) 1501void 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 /* make_request is active */ 1506 /* make_request is active */
1505 *(current->bio_tail) = bio; 1507 bio_list_add(current->bio_list, bio);
1506 bio->bi_next = NULL;
1507 current->bio_tail = &bio->bi_next;
1508 return; 1508 return;
1509 } 1509 }
1510 /* following loop may be a bit non-obvious, and so deserves some 1510 /* following loop may be a bit non-obvious, and so deserves some
@@ -1512,30 +1512,27 @@ void generic_make_request(struct bio *bio)
1512 * Before entering the loop, bio->bi_next is NULL (as all callers 1512 * Before entering the loop, bio->bi_next is NULL (as all callers
1513 * ensure that) so we have a list with a single bio. 1513 * ensure that) so we have a list with a single bio.
1514 * We pretend that we have just taken it off a longer list, so 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 1515 * we assign bio_list to a pointer to the bio_list_on_stack,
1516 * to &bio_list, thus initialising the bio_list of new bios to be 1516 * thus initialising the bio_list of new bios to be
1517 * added. __generic_make_request may indeed add some more bios 1517 * added. __generic_make_request may indeed add some more bios
1518 * through a recursive call to generic_make_request. If it 1518 * through a recursive call to generic_make_request. If it
1519 * did, we find a non-NULL value in bio_list and re-enter the loop 1519 * did, we find a non-NULL value in bio_list and re-enter the loop
1520 * from the top. In this case we really did just take the bio 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 1521 * of the top of the list (no pretending) and so remove it from
1522 * bio_tail or bi_next, and call into __generic_make_request again. 1522 * bio_list, and call into __generic_make_request again.
1523 * 1523 *
1524 * The loop was structured like this to make only one call to 1524 * The loop was structured like this to make only one call to
1525 * __generic_make_request (which is important as it is large and 1525 * __generic_make_request (which is important as it is large and
1526 * inlined) and to keep the structure simple. 1526 * inlined) and to keep the structure simple.
1527 */ 1527 */
1528 BUG_ON(bio->bi_next); 1528 BUG_ON(bio->bi_next);
1529 bio_list_init(&bio_list_on_stack);
1530 current->bio_list = &bio_list_on_stack;
1529 do { 1531 do {
1530 current->bio_list = bio->bi_next;
1531 if (bio->bi_next == NULL)
1532 current->bio_tail = &current->bio_list;
1533 else
1534 bio->bi_next = NULL;
1535 __generic_make_request(bio); 1532 __generic_make_request(bio);
1536 bio = current->bio_list; 1533 bio = bio_list_pop(current->bio_list);
1537 } while (bio); 1534 } while (bio);
1538 current->bio_tail = NULL; /* deactivate */ 1535 current->bio_list = NULL; /* deactivate */
1539} 1536}
1540EXPORT_SYMBOL(generic_make_request); 1537EXPORT_SYMBOL(generic_make_request);
1541 1538
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 78efe7c485ac..7eb82975e1ee 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -97,7 +97,7 @@ struct sched_param {
97struct exec_domain; 97struct exec_domain;
98struct futex_pi_state; 98struct futex_pi_state;
99struct robust_list_head; 99struct robust_list_head;
100struct bio; 100struct bio_list;
101struct fs_struct; 101struct fs_struct;
102struct bts_context; 102struct bts_context;
103struct perf_event_context; 103struct perf_event_context;
@@ -1466,7 +1466,7 @@ struct task_struct {
1466 void *journal_info; 1466 void *journal_info;
1467 1467
1468/* stacked block device info */ 1468/* stacked block device info */
1469 struct bio *bio_list, **bio_tail; 1469 struct bio_list *bio_list;
1470 1470
1471/* VM state */ 1471/* VM state */
1472 struct reclaim_state *reclaim_state; 1472 struct reclaim_state *reclaim_state;