I found a couple of small linked list bugs in __make_request() in
drivers/block/ll_rw_blk.c. The bugs exist in both kernels
2.4.20 and 2.5.69. Therefore I have made patches for both
kernels. The problem is that when inserting a new buffer_head
into the linked list of buffer_head structures maintained by
"struct request", the b_reqnext field is not initialized.
-Dave Peterson
dsp@llnl.gov
========== START OF 2.4.20 PATCH FOR drivers/block/ll_rw_blk.c ===========
--- ll_rw_blk.c.old Wed May 7 15:54:58 2003
+++ ll_rw_blk.c.new Wed May 7 15:58:07 2003
@@ -973,6 +973,7 @@
insert_here = &req->queue;
break;
}
+ bh->b_reqnext = req->bhtail->b_reqnext;
req->bhtail->b_reqnext = bh;
req->bhtail = bh;
req->nr_sectors = req->hard_nr_sectors += count;
@@ -1061,6 +1062,7 @@
req->waiting = NULL;
req->bh = bh;
req->bhtail = bh;
+ bh->b_reqnext = NULL;
req->rq_dev = bh->b_rdev;
req->start_time = jiffies;
req_new_io(req, 0, count);
========== END OF 2.4.20 PATCH FOR drivers/block/ll_rw_blk.c =============
========== START OF 2.5.69 PATCH FOR drivers/block/ll_rw_blk.c ===========
--- ll_rw_blk.c.old Wed May 7 15:55:18 2003
+++ ll_rw_blk.c.new Wed May 7 16:01:56 2003
@@ -1721,6 +1721,7 @@
break;
}
+ bio->bi_next = req->biotail->bi_next;
req->biotail->bi_next = bio;
req->biotail = bio;
req->nr_sectors = req->hard_nr_sectors += nr_sectors;
@@ -1811,6 +1812,7 @@
req->buffer = bio_data(bio); /* see ->buffer comment above */
req->waiting = NULL;
req->bio = req->biotail = bio;
+ bio->bi_next = NULL;
req->rq_disk = bio->bi_bdev->bd_disk;
req->start_time = jiffies;
add_request(q, req, insert_here);
========== END OF 2.5.69 PATCH FOR drivers/block/ll_rw_blk.c =============
-
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This archive was generated by hypermail 2b29 : Wed May 07 2003 - 22:00:33 EST