Re: [PATCH] pktcdvd.c: Fix wrong return code when alloc_disk() fails.

[Jens Axboe]

On 8/14/18 9:22 PM, Jiecheng Wu wrote:
> Function pkt_setup_dev() defined in drivers/block/pktcdvd.c calls
> alloc_disk(). However, it forgets to set the error return code when
> alloc_disk() fails. Instead, when alloc_disk() fails, it simply jumps
> to label 'out_mem' leaving the variable ret unchanged.

We do init it to -ENOMEM, the problem is that
mempool_init_kmalloc_pool() overwrites it, and any unset jump to error
out after that won't work so well.

So your fix isn't complete, since it won't catch blk_alloc_queue()
failure. The below should do it.


diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index e285413d4a75..6f1d25c1eb64 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2740,6 +2740,7 @@ static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev)
        pd->write_congestion_on  = write_congestion_on;
        pd->write_congestion_off = write_congestion_off;
 
+       ret = -ENOMEM;
        disk = alloc_disk(1);
        if (!disk)
                goto out_mem;

-- 
Jens Axboe