svn commit: r253644 - head/sys/dev/ata/chipsets

[Alexander Motin]

On 25.07.2013 19:14, John Baldwin wrote:
> On Thursday, July 25, 2013 5:12:46 am Alexander Motin wrote:
>> Author: mav
>> Date: Thu Jul 25 09:12:46 2013
>> New Revision: 253644
>> URL: http://svnweb.freebsd.org/changeset/base/253644
>>
>> Log:
>>    Add missing NULL check after malloc(M_NOWAIT).
>>
>>    Submitted by:	Dmitry Luhtionov <dmitryluhtionov at gmail.com>
>>
>> Modified:
>>    head/sys/dev/ata/chipsets/ata-promise.c
>>
>> Modified: head/sys/dev/ata/chipsets/ata-promise.c
>> ==============================================================================
>> --- head/sys/dev/ata/chipsets/ata-promise.c	Thu Jul 25 08:41:22 2013	(r253643)
>> +++ head/sys/dev/ata/chipsets/ata-promise.c	Thu Jul 25 09:12:46 2013	(r253644)
>> @@ -287,6 +287,10 @@ ata_promise_chipinit(device_t dev)
>>   	    /* setup host packet controls */
>>   	    hpkt = malloc(sizeof(struct ata_promise_sx4),
>>   			  M_ATAPCI, M_NOWAIT | M_ZERO);
>> +	    if (hpkt == NULL) {
>> +		device_printf(dev, "Cannot allocate HPKT\n");
>> +		goto failnfree;
>> +	    }
>>   	    mtx_init(&hpkt->mtx, "ATA promise HPKT lock", NULL, MTX_DEF);
>>   	    TAILQ_INIT(&hpkt->queue);
>>   	    hpkt->busy = 0;
>
> Why not use M_WAITOK here?

I have no strong opinion. I was going to do it first because only Giant 
is held at that point. But looking on different device_XXX() internals 
and other code I've found that they prefer to use M_NOWAIT in alike 
places. While Giant allows sleeping, it is dropped during sleep, that I 
guess is not really safe.

-- 
Alexander Motin