From: Andreas Schwab <schwab@suse.de>
To: Quentin Schulz <quentin.schulz@bootlin.com>
Cc: andrew@lunn.ch, alexandre.belloni@bootlin.com,
f.fainelli@gmail.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, allan.nielsen@microchip.com,
thomas.petazzoni@bootlin.com, linux-riscv@lists.infradead.org,
davem@davemloft.net
Subject: Re: [PATCH net-next v3 1/6] net: phy: mscc: migrate to phy_select/restore_page functions
Date: Mon, 19 Nov 2018 15:57:17 +0100 [thread overview]
Message-ID: <mvm8t1pazea.fsf@suse.de> (raw)
Message-ID: <20181119145717.O7CVyvrtGGZ0ueePpuJ7g8Wo1bZJy3Uw4v0dORpuOT4@z> (raw)
In-Reply-To: <20181008100728.24959-2-quentin.schulz@bootlin.com> (Quentin Schulz's message of "Mon, 8 Oct 2018 12:07:23 +0200")
On Okt 08 2018, Quentin Schulz <quentin.schulz@bootlin.com> wrote:
> The Microsemi PHYs have multiple banks of registers (called pages).
> Registers can only be accessed from one page, if we need a register from
> another page, we need to switch the page and the registers of all other
> pages are not accessible anymore.
>
> Basically, to read register 5 from page 0, 1, 2, etc., you do the same
> phy_read(phydev, 5); but you need to set the desired page beforehand.
>
> In order to guarantee that two concurrent functions do not change the
> page, we need to do some locking per page. This can be achieved with the
> use of phy_select_page and phy_restore_page functions but phy_write/read
> calls in-between those two functions shall be replaced by their
> lock-free alternative __phy_write/read.
>
> Let's migrate this driver to those functions.
This has some serious locking problem.
[<0>] __schedule+0x25e/0x74c
[<0>] schedule+0x1a/0x58
[<0>] schedule_preempt_disabled+0xc/0x14
[<0>] __mutex_lock.isra.0+0x10e/0x22e
[<0>] __mutex_lock_slowpath+0xe/0x16
[<0>] mutex_lock+0x22/0x2a
[<0>] mdiobus_read+0x36/0x60
[<0>] vsc85xx_config_init+0x4c/0x1e2
[<0>] phy_init_hw+0x3c/0x52
[<0>] phy_attach_direct+0xec/0x1dc
[<0>] phy_connect_direct+0x1a/0x56
[<0>] macb_probe+0x800/0xb5e [macb]
[<0>] platform_drv_probe+0x3e/0x7e
[<0>] really_probe+0xba/0x310
[<0>] driver_probe_device+0x54/0xf2
[<0>] __driver_attach+0xde/0x106
[<0>] bus_for_each_dev+0x4a/0x72
[<0>] driver_attach+0x1a/0x22
[<0>] bus_add_driver+0x1ce/0x212
[<0>] driver_register+0x3a/0xd0
[<0>] __platform_driver_register+0x3a/0x42
[<0>] macb_driver_init+0x20/0x28 [macb]
[<0>] do_one_initcall+0x48/0x128
[<0>] do_init_module+0x4a/0x186
[<0>] load_module+0xd6a/0xe6a
[<0>] sys_finit_module+0xc6/0xfc
[<0>] check_syscall_nr+0x22/0x22
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
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next parent reply other threads:[~2018-11-19 14:57 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20181008100728.24959-1-quentin.schulz@bootlin.com>
[not found] ` <20181008100728.24959-2-quentin.schulz@bootlin.com>
2018-11-19 14:57 ` Andreas Schwab [this message]
2018-11-19 14:57 ` [PATCH net-next v3 1/6] net: phy: mscc: migrate to phy_select/restore_page functions Andreas Schwab
2018-11-19 15:10 ` Andrew Lunn
2018-11-19 15:10 ` Andrew Lunn
2018-11-19 15:13 ` Andreas Schwab
2018-11-19 15:13 ` Andreas Schwab
2018-11-19 15:28 ` Andrew Lunn
2018-11-19 15:28 ` Andrew Lunn
2018-11-19 15:40 ` Alexandre Belloni
2018-11-19 15:40 ` Alexandre Belloni
2018-11-19 15:50 ` Andreas Schwab
2018-11-19 15:50 ` Andreas Schwab
2018-11-19 16:12 ` Andrew Lunn
2018-11-19 16:12 ` Andrew Lunn
2018-11-19 16:14 ` Andreas Schwab
2018-11-19 16:14 ` Andreas Schwab
2018-11-19 16:25 ` Andrew Lunn
2018-11-19 16:25 ` Andrew Lunn
2018-11-19 16:32 ` Andreas Schwab
2018-11-19 16:32 ` Andreas Schwab
2018-11-19 16:44 ` Andrew Lunn
2018-11-19 16:44 ` Andrew Lunn
2018-11-20 11:39 ` Andreas Schwab
2018-11-20 11:39 ` Andreas Schwab
2018-11-20 13:20 ` Quentin Schulz
2018-11-20 13:20 ` Quentin Schulz
2018-11-20 13:48 ` [PATCH] net: phy: mscc: fix locking in vsc85xx_default_config Andreas Schwab
2018-11-20 13:48 ` Andreas Schwab
2018-11-20 13:55 ` Quentin Schulz
2018-11-20 13:55 ` Quentin Schulz
2018-11-20 14:01 ` Andreas Schwab
2018-11-20 14:01 ` Andreas Schwab
2018-11-20 14:17 ` Quentin Schulz
2018-11-20 14:17 ` Quentin Schulz
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