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From: "Zoltán Böszörményi" <zboszor@pr.hu>
To: linux-kernel@vger.kernel.org
Cc: linux-usb@vger.kernel.org, linux-watchdog@vger.kernel.org,
	linux-i2c@vger.kernel.org,
	"Paul Menzel" <paulepanter@users.sourceforge.net>,
	"Christian Fetzer" <fetzer.ch@gmail.com>,
	"Jean Delvare" <jdelvare@suse.com>,
	"Nehal Shah" <nehal-bakulchandra.shah@amd.com>,
	"Tim Small" <tim@seoss.co.uk>,
	"Guenter Roeck" <linux@roeck-us.net>,
	kernel@ekass.net, wim@iguana.be, jlayton@poochiereds.net,
	marc.2377@gmail.com, cshorler@googlemail.com, wsa@the-dreams.de,
	regressions@leemhuis.info, "Zoltán Böszörményi" <zboszor@pr.hu>
Subject: [PATCH 2/5 v2] Modify behaviour of request_*muxed_region()
Date: Thu, 22 Jun 2017 15:21:31 +0200	[thread overview]
Message-ID: <20170622132134.7200-3-zboszor@pr.hu> (raw)
In-Reply-To: <20170622132134.7200-1-zboszor@pr.hu>

In order to make request_*muxed_region() behave more like
mutex_lock(), a possible failure case needs to be eliminated.
When drivers do not properly share the same I/O region, e.g.
one is using request_region() and the other is using
request_muxed_region(), the kernel didn't warn the user about it.
This change modifies IORESOURCE_MUXED behaviour so it always
goes to sleep waiting for the resuorce to be freed and the
inconsistent resource flag usage is logged with KERN_ERR.

v2: Fixed checkpatch.pl warnings and extended the comment
    about request_declared_muxed_region.

Signed-off-by: Zoltán Böszörményi <zboszor@pr.hu>
---
 kernel/resource.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 2be7029..5df2731 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1125,6 +1125,7 @@ resource_size_t resource_alignment(struct resource *res)
  *
  * request_declared_muxed_region creates a new shared busy region
  * described in an existing resource descriptor.
+ * It only returns if it succeeded.
  *
  * release_region releases a matching busy region.
  * The region is only freed if it was allocated.
@@ -1191,7 +1192,10 @@ struct resource *__request_declared_region(struct resource *parent,
 				continue;
 			}
 		}
-		if (conflict->flags & flags & IORESOURCE_MUXED) {
+		if (flags & IORESOURCE_MUXED) {
+			if (!(conflict->flags & IORESOURCE_MUXED))
+				pr_err("Resource conflict between muxed \"%s\" and non-muxed \"%s\" I/O regions!\n",
+					res->name, conflict->name);
 			add_wait_queue(&muxed_resource_wait, &wait);
 			write_unlock(&resource_lock);
 			set_current_state(TASK_UNINTERRUPTIBLE);
-- 
2.9.4

  parent reply	other threads:[~2017-06-22 13:22 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <<20170401110223.12056-1-zboszor@pr.hu>
2017-04-03  7:51 ` [PATCH 0/3 v2] Fix regression in the sp5100_tco driver Zoltan Boszormenyi
2017-04-03  7:51   ` [PATCH 1/3 v2] usb: pci-quirks: Add a common mutex for the I/O port pair of SB800 Zoltan Boszormenyi
2017-06-20 14:12     ` [1/3, " Guenter Roeck
2017-04-03  7:51   ` [PATCH 2/3 v2] i2c: i2c-piix4: Use the common mutex Zoltan Boszormenyi
2017-04-19 18:43     ` Wolfram Sang
2017-04-03  7:51   ` [PATCH 3/3 v2] watchdog: sp5100_tco: " Zoltan Boszormenyi
2017-06-21  3:53   ` [PATCH 0/5 v3] Fix sp5100_tco watchdog driver regression Zoltán Böszörményi
2017-06-21  3:53     ` [PATCH 1/5] Extend the request_region() infrastructure Zoltán Böszörményi
2017-06-21  3:53     ` [PATCH 2/5] Modify behaviour of request_*muxed_region() Zoltán Böszörményi
2017-06-21  3:53     ` [PATCH 3/5] usb: pci-quirks: Protect the I/O port pair of SB800 Zoltán Böszörményi
2017-06-21  3:53     ` [PATCH 4/5] i2c: i2c-piix4: Use request_declared_muxed_region() Zoltán Böszörményi
2017-06-21  3:53     ` [PATCH 5/5] watchdog: sp5100_tco: " Zoltán Böszörményi
2017-06-21 15:09       ` Guenter Roeck
2017-06-22 13:21     ` [PATCH 0/5 v4] Fix sp5100_tco watchdog driver regression Zoltán Böszörményi
2017-06-22 13:21       ` [PATCH 1/5 v2] Extend the request_region() infrastructure Zoltán Böszörményi
2017-07-14  8:33         ` Boszormenyi Zoltan
2017-06-22 13:21       ` Zoltán Böszörményi [this message]
2017-07-08 15:37         ` [2/5,v2] Modify behaviour of request_*muxed_region() Guenter Roeck
2017-06-22 13:21       ` [PATCH 3/5 v4] usb: pci-quirks: Protect the I/O port pair of SB800 Zoltán Böszörményi
2017-07-14  8:34         ` Boszormenyi Zoltan
2017-07-14 11:36           ` Greg Kroah-Hartman
2017-06-22 13:21       ` [PATCH 4/5 v4] i2c: i2c-piix4: Use request_declared_muxed_region() Zoltán Böszörményi
2017-06-22 13:21       ` [PATCH 5/5 v4] watchdog: sp5100_tco: " Zoltán Böszörményi
2017-07-14  8:34         ` Boszormenyi Zoltan
2017-07-06  7:50       ` [PATCH 0/5 v4] Fix sp5100_tco watchdog driver regression Boszormenyi Zoltan
     [not found]         ` <CAETC-g-0ZYiD=j_sAtYpfr0t-rciiTx3ruvpGuwEud+nbbpiBg@mail.gmail.com>
     [not found]           ` <CAETC-g_YF7TWv+LNrNQrX9AY_-iepCeE0EmCKWYF4VyQzRY+UQ@mail.gmail.com>
2017-07-07  2:26             ` Marcelo "Marc" Ranolfi
2017-04-01 10:06 [PATCH 0/3] " Zoltán Böszörményi
2017-04-01 10:06 ` [PATCH 1/3] usb: pci-quirks: Add a header for SB800 I/O ports and mutex for locking Zoltán Böszörményi
2017-04-01 10:06 ` [PATCH 3/3] watchdog: sp5100_tco: Synchronize I/O port accesses Zoltán Böszörményi
2017-04-01 11:02 ` [PATCH 0/3, resend] Fix sp5100_tco watchdog driver regression Zoltan Boszormenyi
2017-04-01 11:02   ` [PATCH 1/3] usb: pci-quirks: Add a header for SB800 I/O ports and mutex for locking Zoltan Boszormenyi
2017-04-01 13:59     ` Greg KH
2017-04-01 14:40       ` Alan Stern
2017-04-01 15:09         ` Boszormenyi Zoltan
2017-04-01 15:07       ` Boszormenyi Zoltan
2017-04-01 11:02   ` [PATCH 3/3] watchdog: sp5100_tco: Synchronize I/O port accesses Zoltan Boszormenyi
2017-04-01 11:08 ` [PATCH 2/3] i2c: i2c-piix4: Synchronize I/O port accesses with the SB800 USB quirk Zoltan Boszormenyi

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