Re: [PATCH libata/for-3.16-fixes] libata: introduce ata_host->n_tags to avoid oops on SAS controllers

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello,

On Wed, Jul 23, 2014 at 06:46:05PM +0200, Bartlomiej Zolnierkiewicz wrote:
> On Wednesday, July 23, 2014 12:36:01 PM Tejun Heo wrote:
> BTW:
> 		/* the last tag is reserved for internal command. */
> 		if (tag == ATA_TAG_INTERNAL)
> 			continue;
> 
> in ata_qc_new()'s loop now becomes a dead code (loop will be done
> maximum ATA_MAX_QUEUE - 2 times and ATA_TAG_INTERNAL is defined
> as ATA_MAX_QUEUE - 1).  Compiler can probably optimize it away so
> as a bonus of your patch we may get one condition check less in
> a hot-path. :)

ATA_TAG_INTERNAL will soon be replaced by a qc flag so this should all
go away pretty soon.  ata_qc_new() is quite badly implemented tho.  It
has no reason to do atomic test_and_set_bit() and there are far more
efficient ways to implement what it does.  If anybody is interested in
improving it, please go ahead.

Thanks.

-- 
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Filesystems]     [Linux SCSI]     [Linux RAID]     [Git]     [Kernel Newbies]     [Linux Newbie]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Samba]     [Device Mapper]

  Powered by Linux