Messages in this thread Patch in this message |  | | | Date | Mon, 21 Nov 2005 15:54:46 +0100 | | From | Jens Axboe <> | | Subject | Re: Linux 2.6.14: Badness in as-iosched |
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On Thu, Nov 10 2005, Brice Goglin wrote: > Hi Jens, > > I just hit a badness (actually, tons of badness like this) in as-iosched > while ripping > an audio CD with ripperX (with cdparanoia as a backend). > I was using 2.6.14 on an IBM Thinkpad R52. The kernel has been compiled with > gcc-4.0.2-2 (Debian testing). > > The first badness in dmesg is: > > cdrom: dropping to single frame dma > arq->state: 4 > Badness in as_insert_request at drivers/block/as-iosched.c:1519 > [<c0237410>] as_insert_request+0x70/0x1d0 > [<c022dc25>] __elv_add_request+0xa5/0xe0 > [<c022dc8b>] elv_add_request+0x2b/0x40 > [<c0230fe6>] blk_execute_rq_nowait+0x46/0x60 > [<c023107a>] blk_execute_rq+0x7a/0xe0 > [<c0231310>] blk_end_sync_rq+0x0/0x30 > [<c0160b77>] bio_phys_segments+0x27/0x30 > [<c0232610>] blk_rq_bio_prep+0x40/0xb0 > [<c0230dc7>] blk_rq_map_user+0xb7/0xf0 > [<c026bc32>] cdrom_read_cdda_bpc+0x182/0x210 > [<c026bd1b>] cdrom_read_cdda+0x5b/0xc0
Similar case was posted yesterday (I realize yours is older, just missed it the first time around), see my explanation here:
http://lkml.org/lkml/2005/11/20/119
And work-around below.
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c index 1539603..7540d27 100644 --- a/drivers/cdrom/cdrom.c +++ b/drivers/cdrom/cdrom.c @@ -2089,7 +2089,7 @@ static int cdrom_read_cdda_bpc(struct cd int lba, int nframes) { request_queue_t *q = cdi->disk->queue; - struct request *rq; + struct request *rq = NULL; struct bio *bio; unsigned int len; int nr, ret = 0; @@ -2097,13 +2097,13 @@ static int cdrom_read_cdda_bpc(struct cd if (!q) return -ENXIO; - rq = blk_get_request(q, READ, GFP_KERNEL); - if (!rq) - return -ENOMEM; - cdi->last_sense = 0; while (nframes) { + rq = blk_get_request(q, READ, GFP_KERNEL); + if (!rq) + return -ENOMEM; + nr = nframes; if (cdi->cdda_method == CDDA_BPC_SINGLE) nr = 1; @@ -2151,9 +2151,13 @@ static int cdrom_read_cdda_bpc(struct cd nframes -= nr; lba += nr; ubuf += len; + blk_put_request(rq); + rq = NULL; } - blk_put_request(rq); + if (rq) + blk_put_request(rq); + return ret; } -- Jens Axboe
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