Re: [PATCH] sata_nv: fix ADMA ATAPI issues with memory over 4GB

[Mark Lord <liml@rtr.ca>]

Tejun Heo wrote:
> Robert Hancock wrote:
>> Tejun Heo wrote:
..
>> Yes, it should likely do something with these return values. Though
>> theoretically it shouldn't fail, since the DMA mask is either 32-bit,
>> which shouldn't fail, or one that was successfully set before. Also I
>> don't think the SCSI layer actually checks the slave_config return
>> value.. sigh.
> 
> Then please at least add WARN_ON() && another reason why allocating /
> deallocating resources from ->slave_config isn't such a good idea.
..

The entire point of "slave_configure" is to provide a point for the LLD
to do per-device data structure allocation/init.

And yes, SCSI does check the return code.  Whether the code around that check
is buggy or not is another question, but it's always worked for me.

>        if (sdev->host->hostt->slave_configure) {
>                 int ret = sdev->host->hostt->slave_configure(sdev);
>                 if (ret) {
>                         /*
>                          * if LLDD reports slave not present, don't clutter
>                          * console with alloc failure messages
>                          */
>                         if (ret != -ENXIO) {
>                                 sdev_printk(KERN_ERR, sdev,
>                                         "failed to configure device\n");
>                         }
>                         return SCSI_SCAN_NO_RESPONSE;
>                 }
>         }


Cheers