[PATCH v2 20/30] cxlflash: Correct usage of scsi_host_put()

[Matthew R. Ochs]

> On Sep 22, 2015, at 3:53 PM, Brian King <brking at linux.vnet.ibm.com> wrote:
> On 09/16/2015 04:30 PM, Matthew R. Ochs wrote:
>> Currently, scsi_host_put() is being called prematurely in the
>> remove path and is missing entirely in an error cleanup path.
>> The former can lead to memory being freed too early with
>> subsequent access potentially corrupting data whilst the former
>> would result in a memory leak.
>> 
>> Move the usage on remove to be the last cleanup action taken
>> and introduce a call to scsi_host_put() in the one initialization
>> error path that does not use remove to cleanup.
>> 
>> Signed-off-by: Matthew R. Ochs <mrochs at linux.vnet.ibm.com>
>> Signed-off-by: Manoj N. Kumar <manoj at linux.vnet.ibm.com>
>> ---
>> drivers/scsi/cxlflash/main.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
>> index fc77cd4..1856a73 100644
>> --- a/drivers/scsi/cxlflash/main.c
>> +++ b/drivers/scsi/cxlflash/main.c
>> @@ -734,7 +734,6 @@ static void cxlflash_remove(struct pci_dev *pdev)
>> 	case INIT_STATE_SCSI:
>> 		cxlflash_term_local_luns(cfg);
>> 		scsi_remove_host(cfg->host);
>> -		scsi_host_put(cfg->host);
>> 		/* Fall through */
>> 	case INIT_STATE_AFU:
>> 		term_afu(cfg);
>> @@ -744,6 +743,7 @@ static void cxlflash_remove(struct pci_dev *pdev)
>> 	case INIT_STATE_NONE:
>> 		flush_work(&cfg->work_q);
>> 		free_mem(cfg);
>> +		scsi_host_put(cfg->host);
>> 		break;
>> 	}
>> 
>> @@ -2415,6 +2415,7 @@ static int cxlflash_probe(struct pci_dev *pdev,
>> 		dev_err(&pdev->dev, "%s: call to scsi_host_alloc failed!\n",
> 
> This message text is wrong. Its the call to alloc_mem that has failed in this
> leg, not the call to scsi_host_alloc.

Good find. I'll fix this in a separate patch.


-matt