Re: [patch ide-dev 8/9] make ide_task_ioctl() use REQ_DRIVE_TASKFILE

[Tejun Heo <htejun@gmail.com>]

 Hello,

On Tue, Mar 01, 2005 at 09:42:18AM +0100, Bartlomiej Zolnierkiewicz wrote:
> Hello,
> 
> On Tue, 1 Mar 2005 13:21:16 +0900, Tejun Heo <htejun@gmail.com> wrote:
> > 
> >  So, how do you like the following set of TFLAG's?
> > 
> > /* struct ata_taskfile flags */
> > 
> > /* The following six flags are used by IDE driver to control register IO. */
> > ATA_TFLAG_OUT_LBA48             = (1 <<  0), /* enable 48-bit LBA and HOB out */
> 
> aggregate ATA_TFLAG_OUT_HOB_LBA{L,M,H}?
> 
> > ATA_TFLAG_OUT_ADDR              = (1 <<  1), /* enable out to nsect/lba regs */
> 
> not needed currently, add it {when,if} it is needed
> 

 Sure, I'll add flags on as-needed basis.  I was trying to show where
I'm heading.

> > ATA_TFLAG_OUT_DEVICE            = (1 <<  2), /* enable out to device reg */
> > ATA_TFLAG_IN_LBA48              = (1 <<  3), /* enable 48-bit LBA and HOB in */
> 
> aggregate ATA_TFLAG_IN_HOB_LBA_{L,M,H}?
> 
> > ATA_TFLAG_IN_ADDR               = (1 <<  4), /* enable in from nsect/lba regs */
> 
> not needed currently, add it {when,if} it is needed
> 
> > ATA_TFLAG_IN_DEVICE             = (1 <<  5), /* enable in from device reg */
> > 
> > /* These three aggregate flags are used by libata, as it doesn't
> >    really need to optimize register INs */
> > ATA_TFLAG_LBA48                 = (ATA_TFLAG_OUT_LBA48  | ATA_TFLAG_IN_LBA48),
> > ATA_TFLAG_ISADDR                = (ATA_TFLAG_OUT_ADDR   | ATA_TFLAG_IN_ADDR),
> > ATA_TFLAG_DEVICE                = (ATA_TFLAG_OUT_DEVICE | ATA_TFLAG_IN_DEVICE),
> > 
> > ATA_TFLAG_WRITE                 = (1 <<  6), /* data dir */
> > 
> > /* The rest of TFLAGs are only for implementing ioctl direct drive
> >    commands in the IDE driver.  DO NOT use in other places. */
> > ATA_TFLAG_IO_16BIT              = (1 << 11),
> > 
> > ATA_TFLAG_OUT_FEATURE           = (1 << 12),
> > ATA_TFLAG_OUT_NSECT             = (1 << 13),
> > ATA_TFLAG_OUT_LBAL              = (1 << 14),
> > ATA_TFLAG_OUT_LBAM              = (1 << 15),
> > ATA_TFLAG_OUT_LBAH              = (1 << 16),
> > ATA_TFLAG_OUT_HOB_FEATURE       = (1 << 17),
> > ATA_TFLAG_OUT_HOB_NSECT         = (1 << 18),
> > ATA_TFLAG_OUT_HOB_LBAL          = (1 << 19),
> > ATA_TFLAG_OUT_HOB_LBAM          = (1 << 20),
> > ATA_TFLAG_OUT_HOB_LBAH          = (1 << 21),
> > 
> > ATA_TFLAG_IN_FEATURE            = (1 << 22),
> > ATA_TFLAG_IN_NSECT              = (1 << 23),
> > ATA_TFLAG_IN_LBAL               = (1 << 24),
> > ATA_TFLAG_IN_LBAM               = (1 << 25),
> > ATA_TFLAG_IN_LBAH               = (1 << 26),
> > ATA_TFLAG_IN_HOB_FEATURE        = (1 << 27),
> > ATA_TFLAG_IN_HOB_NSECT          = (1 << 28),
> > ATA_TFLAG_IN_HOB_LBAL           = (1 << 29),
> > ATA_TFLAG_IN_HOB_LBAM           = (1 << 30),
> > ATA_TFLAG_IN_HOB_LBAH           = (1 << 31),
> 
> proposed changes will get rid of 4 bits
> 
> > ATA_TFLAG_OUT_MASK              = 0x007ff000,
> > ATA_TFLAG_IN_MASK               = 0xffc00000,
> > ATA_TFLAG_OUT_IN_MASK           = (ATA_TFLAG_OUT_MASK | ATA_TFLAG_IN_MASK),
> > 
> >  ATA_TFLAG_{OUT|IN}_{LBA48|ADDR|DEVICE} should provide enough
> > granuality for fs/internal requests without much hassle, and
> > individual IO/OUT flags will only be used to implement ioctls in
> > separate IN/OUT functions, something like ide_{load|read}_ioctl_task().
> 
> They would be later used by IDE driver itself so names
> like ide_discrete_tf_{load,read}() suits it better IMHO.
> 
> >  Would using more specific prefix for ioctl flags - like
> > ATA_TFLAG_IOC_{IN|OUT}_* - be better?
> 
> Nope, they are not limited to ioctls by design.
>  

 The reason why I separated the flags into two sets is that if we
define IO flags as aggregate of separate flags, we'll end up with
do_rw_taskfile() or something equivalent which handle both normal
(fs/kernel-internal) and ioctl taskfiles, by design.  From previous
discussions, I kind of have the impression that you wanna separate the
fully-flagged taskfile handling from the normal, supposedly simpler,
taskfile handling.  So, I was aiming for IO control flags with similar
granuality w/ the current libata implementation.

 IMHO, handling both in the same path is better.  It would be
simpler/cleaner and, with simple optimizations, there would be
virtually no overhead.

 So, here's the second proposal of the flags.

/* struct ata_taskfile flags */

/* Individual register IO control flags */
ATA_TFLAG_OUT_FEATURE		= (1 <<  0),
ATA_TFLAG_OUT_NSECT		= (1 <<  1),
ATA_TFLAG_OUT_LBAL		= (1 <<  2),
ATA_TFLAG_OUT_LBAM		= (1 <<  3),
ATA_TFLAG_OUT_LBAH		= (1 <<  4),
ATA_TFLAG_OUT_HOB_FEATURE	= (1 <<  5),
ATA_TFLAG_OUT_HOB_NSECT		= (1 <<  6),
ATA_TFLAG_OUT_HOB_LBAL		= (1 <<  7),
ATA_TFLAG_OUT_HOB_LBAM		= (1 <<  8),
ATA_TFLAG_OUT_HOB_LBAH		= (1 <<  9),
ATA_TFLAG_OUT_DEVICE		= (1 << 10),

ATA_TFLAG_IN_FEATURE		= (1 << 11),
ATA_TFLAG_IN_NSECT		= (1 << 12),
ATA_TFLAG_IN_LBAL		= (1 << 13),
ATA_TFLAG_IN_LBAM		= (1 << 14),
ATA_TFLAG_IN_LBAH		= (1 << 15),
ATA_TFLAG_IN_HOB_FEATURE	= (1 << 16),
ATA_TFLAG_IN_HOB_NSECT		= (1 << 17),
ATA_TFLAG_IN_HOB_LBAL		= (1 << 18),
ATA_TFLAG_IN_HOB_LBAM		= (1 << 19),
ATA_TFLAG_IN_HOB_LBAH		= (1 << 20),
ATA_TFLAG_IN_DEVICE		= (1 << 21),

/* The following four aggreate flags are used by IDE to control register IO. */
ATA_TFLAG_OUT_LBA48		= (ATA_TFLAG_OUT_HOB_FEATURE	|
				   ATA_TFLAG_OUT_HOB_NSECT	|
				   ATA_TFLAG_OUT_HOB_LBAL	|
				   ATA_TFLAG_OUT_HOB_LBAM	|
				   ATA_TFLAG_OUT_HOB_LBAH	),
ATA_TFLAG_OUT_ADDR		= (ATA_TFLAG_OUT_FEATURE	|
				   ATA_TFLAG_OUT_NSECT		|
				   ATA_TFLAG_OUT_LBAL		|
				   ATA_TFLAG_OUT_LBAM		|
				   ATA_TFLAG_OUT_LBAH		),
ATA_TFLAG_IN_LBA48		= (ATA_TFLAG_IN_HOB_FEATURE	|
				   ATA_TFLAG_IN_HOB_NSECT	|
				   ATA_TFLAG_IN_HOB_LBAL	|
				   ATA_TFLAG_IN_HOB_LBAM	|
				   ATA_TFLAG_IN_HOB_LBAH	),
ATA_TFLAG_IN_ADDR		= (ATA_TFLAG_IN_FEATURE		|
				   ATA_TFLAG_IN_NSECT		|
				   ATA_TFLAG_IN_LBAL		|
				   ATA_TFLAG_IN_LBAM		|
				   ATA_TFLAG_IN_LBAH		),

/* These three aggregate flags are used by libata, as it doesn't
   really need to optimize register INs */
ATA_TFLAG_LBA48			= (ATA_TFLAG_OUT_LBA48  | ATA_TFLAG_IN_LBA48 ),
ATA_TFLAG_ISADDR		= (ATA_TFLAG_OUT_ADDR   | ATA_TFLAG_IN_ADDR  ),
ATA_TFLAG_DEVICE		= (ATA_TFLAG_OUT_DEVICE | ATA_TFLAG_IN_DEVICE),

ATA_TFLAG_WRITE			= (1 << 22), /* data dir */
ATA_TFLAG_IO_16BIT		= (1 << 23), /* force 16bit pio (IDE) */

 Thanks a lot.

-- 
tejun