From: Petko Manolov <petkan@nucleusys.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, oneukum@suse.com,
Petko Manolov <petko.manolov@konsulko.com>
Subject: Re: [PATCH 1/2] net: pegasus: convert control messages to the new send/recv scheme.
Date: Sat, 26 Sep 2020 11:21:08 +0300 [thread overview]
Message-ID: <20200926082108.GA6770@karbon> (raw)
In-Reply-To: <20200926054457.GC631346@kroah.com>
On 20-09-26 07:44:57, Greg KH wrote:
> On Fri, Sep 25, 2020 at 07:01:59PM +0300, Petko Manolov wrote:
> > From: Petko Manolov <petko.manolov@konsulko.com>
> >
> > Move all control transfers to safer usb_control_msg_send/recv() API.
>
> This says _what_ the patch does, but we can see that from the diff. You
> should describe _why_ we are doing what we are doing, so that everyone
> understands the need for the change.
Didn't want to parrot the reason for usb_control_msg_send/recv() existence, but
i guess you're right. 5 years from now i would not remember anything. :)
> > static int set_register(pegasus_t *pegasus, __u16 indx, __u8 data)
> > {
> > - u8 *buf;
> > - int ret;
> > -
> > - buf = kmemdup(&data, 1, GFP_NOIO);
> > - if (!buf)
> > - return -ENOMEM;
> > -
> > - ret = usb_control_msg(pegasus->usb, usb_sndctrlpipe(pegasus->usb, 0),
> > - PEGASUS_REQ_SET_REG, PEGASUS_REQT_WRITE, data,
> > - indx, buf, 1, 1000);
> > - if (ret < 0)
> > - netif_dbg(pegasus, drv, pegasus->net,
> > - "%s returned %d\n", __func__, ret);
> > - kfree(buf);
> > - return ret;
> > + return usb_control_msg_send(pegasus->usb, 0, PEGASUS_REQ_SET_REG,
> > + PEGASUS_REQT_WRITE, data, indx, &data, 1,
> > + 1000, GFP_NOIO);
> > }
>
> Again, why isn't set_register() now rewritten to just be:
>
> static int set_register(pegasus_t *pegasus, __u16 indx, __u8 data)
> {
> return set_registers(pegasus, indx, 1, data);
> }
>
> Much easier to show that it's all converted properly :)
There's a catch - adm8511-based devices can only write to a single register via
specific control request. This request expects the register number in wIndex
and the value in wValue. A bit of a brain fart which is fixed in adm8515.
Admittedly, I could open code set_register() and avoid a kmemdup() call since in
this case 'data' is going to be NULL. However, set_register() isn't heavily
used, except for the setup phase, so i went for the prettier/simpler approach.
Which reminds me that i should put a comment explaining why is that.
cheers,
Petko
next prev parent reply other threads:[~2020-09-26 8:21 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-23 13:43 [RFC] change the new message to provide for memory allocations Oliver Neukum
2020-09-23 13:43 ` [RFC 01/14] Revert "USB: core: hub.c: use usb_control_msg_send() in a few places" Oliver Neukum
2020-09-23 13:43 ` [RFC 02/14] Revert "Bluetooth: ath3k: use usb_control_msg_send() and usb_control_msg_recv()" Oliver Neukum
2020-09-23 13:43 ` [RFC 03/14] Revert "sound: hiface: move to use usb_control_msg_send()" Oliver Neukum
2020-09-23 13:43 ` [RFC 04/14] Revert "sound: line6: move to use usb_control_msg_send() and usb_control_msg_recv()" Oliver Neukum
2020-09-23 13:43 ` [RFC 05/14] Revert "sound: 6fire: " Oliver Neukum
2020-09-23 13:43 ` [RFC 06/14] Revert "sound: usx2y: move to use usb_control_msg_send()" Oliver Neukum
2020-09-23 13:43 ` [RFC 07/14] Revert "USB: legousbtower: use usb_control_msg_recv()" Oliver Neukum
2020-09-23 13:43 ` [RFC 08/14] USB: correct API of usb_control_msg_send/recv Oliver Neukum
2020-09-25 9:31 ` [PATCH 0/2] [usb] Petko Manolov
2020-09-25 9:31 ` [PATCH 1/2] net: pegasus: convert control messages to the new send/recv scheme Petko Manolov
2020-09-25 14:37 ` Greg KH
2020-09-25 16:01 ` [PATCH 0/2] [patch v2] utilize the new control message send and receive API Petko Manolov
2020-09-25 16:01 ` [PATCH 1/2] net: pegasus: convert control messages to the new send/recv scheme Petko Manolov
2020-09-26 5:44 ` Greg KH
2020-09-26 8:21 ` Petko Manolov [this message]
2020-09-26 12:45 ` Greg KH
2020-09-25 16:02 ` [PATCH 2/2] net: rtl8150: " Petko Manolov
2020-09-25 20:14 ` kernel test robot
2020-09-25 16:05 ` [PATCH 1/2] net: pegasus: " Petko Manolov
2020-09-26 5:45 ` Greg KH
2020-09-25 9:31 ` [PATCH 2/2] net: rtl8150: " Petko Manolov
2020-09-25 14:37 ` Greg KH
2020-09-26 9:13 ` [PATCH v3 0/2] Use the new usb control message API Petko Manolov
2020-09-26 9:13 ` [PATCH v3 1/2] net: pegasus: " Petko Manolov
2020-09-26 9:13 ` [PATCH v3 2/2] net: rtl8150: " Petko Manolov
2020-09-27 10:16 ` [PATCH v3 0/2] " Greg KH
2020-09-27 12:56 ` Petko Manolov
2020-09-27 12:49 ` [PATCH RESEND " Petko Manolov
2020-09-27 12:49 ` [PATCH RESEND v3 1/2] net: pegasus: " Petko Manolov
2020-09-27 12:49 ` [PATCH RESEND v3 2/2] net: rtl8150: " Petko Manolov
2020-09-28 23:00 ` [PATCH RESEND v3 0/2] " David Miller
2020-09-29 4:59 ` Petko Manolov
2020-09-29 19:58 ` David Miller
2020-09-30 6:23 ` Greg KH
2020-09-23 13:43 ` [RFC 09/14] sound: usx2y: move to use usb_control_msg_send() Oliver Neukum
2020-09-25 14:32 ` Greg KH
2020-09-23 13:43 ` [RFC 10/14] sound: 6fire: move to use usb_control_msg_send() and usb_control_msg_recv() Oliver Neukum
2020-09-23 13:43 ` [RFC 11/14] USB: legousbtower: use usb_control_msg_recv() Oliver Neukum
2020-09-23 13:43 ` [RFC 12/14] sound: line6: move to use usb_control_msg_send() and usb_control_msg_recv() Oliver Neukum
2020-09-23 13:43 ` [RFC 13/14] sound: hiface: move to use usb_control_msg_send() Oliver Neukum
2020-09-23 13:43 ` [RFC 14/14] Bluetooth: ath3k: use usb_control_msg_send() and usb_control_msg_recv() Oliver Neukum
2020-09-23 17:21 ` [RFC] change the new message to provide for memory allocations Greg KH
2020-09-23 17:32 ` Oliver Neukum
2020-09-23 17:46 ` Greg KH
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