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authorTony Breeds <tony@bakeyournoodle.com>2007-03-05 00:30:14 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-03-05 07:57:51 -0800
commit1ad7c311079412541bebaf1c8436d405cc8c6b2c (patch)
tree579185b75cf968de132d6a2b0cd6d4fd21ff9670 /drivers/cdrom
parent5fdc2abe39b76822e34e7029ca5f69fe4bea58d4 (diff)
downloadlinux-1ad7c311079412541bebaf1c8436d405cc8c6b2c.tar.gz
[PATCH] Fix soft lockup with iSeries viocd driver
Fix soft lockup with iSeries viocd driver, caused by eventually calling end_that_request_first() with nr_bytes 0. Some versions of hald do an SG_IO ioctl on the viocd device which becomes a request with hard_nr_sectors and hard_cur_sectors set to zero. Passing zero as the number of sectors to end_request() (which calls end_that_request_first()) causes an infinite loop when the bio is being freed. This patch makes sure that the zero is never passed. It only requires some number larger the the request size the terminate the loop. The lockup is triggered by hald, interrogating the device. Signed-off-by: Tony Breeds <tony@bakeyournoodle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/cdrom')
-rw-r--r--drivers/cdrom/viocd.c27
1 files changed, 23 insertions, 4 deletions
diff --git a/drivers/cdrom/viocd.c b/drivers/cdrom/viocd.c
index dc13ebacedf..44cd7b2ddf0 100644
--- a/drivers/cdrom/viocd.c
+++ b/drivers/cdrom/viocd.c
@@ -376,6 +376,25 @@ static int send_request(struct request *req)
return 0;
}
+static void viocd_end_request(struct request *req, int uptodate)
+{
+ int nsectors = req->hard_nr_sectors;
+
+ /*
+ * Make sure it's fully ended, and ensure that we process
+ * at least one sector.
+ */
+ if (blk_pc_request(req))
+ nsectors = (req->data_len + 511) >> 9;
+ if (!nsectors)
+ nsectors = 1;
+
+ if (end_that_request_first(req, uptodate, nsectors))
+ BUG();
+ add_disk_randomness(req->rq_disk);
+ blkdev_dequeue_request(req);
+ end_that_request_last(req, uptodate);
+}
static int rwreq;
@@ -385,11 +404,11 @@ static void do_viocd_request(request_queue_t *q)
while ((rwreq == 0) && ((req = elv_next_request(q)) != NULL)) {
if (!blk_fs_request(req))
- end_request(req, 0);
+ viocd_end_request(req, 0);
else if (send_request(req) < 0) {
printk(VIOCD_KERN_WARNING
"unable to send message to OS/400!");
- end_request(req, 0);
+ viocd_end_request(req, 0);
} else
rwreq++;
}
@@ -601,9 +620,9 @@ return_complete:
"with rc %d:0x%04X: %s\n",
req, event->xRc,
bevent->sub_result, err->msg);
- end_request(req, 0);
+ viocd_end_request(req, 0);
} else
- end_request(req, 1);
+ viocd_end_request(req, 1);
/* restart handling of incoming requests */
spin_unlock_irqrestore(&viocd_reqlock, flags);