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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	"Nick Desaulniers" <ndesaulniers@google.com>,
	"Nathan Chancellor" <nathan@kernel.org>,
	"Dávid Bolvanský" <david.bolvansky@gmail.com>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>
Subject: [PATCH 5.4 17/18] drm/i915: Avoid bitwise vs logical OR warning in snb_wm_latency_quirk()
Date: Fri, 14 Jan 2022 09:16:24 +0100	[thread overview]
Message-ID: <20220114081542.044572798@linuxfoundation.org> (raw)
In-Reply-To: <20220114081541.465841464@linuxfoundation.org>

From: Nathan Chancellor <nathan@kernel.org>

commit 2e70570656adfe1c5d9a29940faa348d5f132199 upstream.

A new warning in clang points out a place in this file where a bitwise
OR is being used with boolean types:

drivers/gpu/drm/i915/intel_pm.c:3066:12: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical]
        changed = ilk_increase_wm_latency(dev_priv, dev_priv->wm.pri_latency, 12) |
                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This construct is intentional, as it allows every one of the calls to
ilk_increase_wm_latency() to occur (instead of short circuiting with
logical OR) while still caring about the result of each call.

To make this clearer to the compiler, use the '|=' operator to assign
the result of each ilk_increase_wm_latency() call to changed, which
keeps the meaning of the code the same but makes it obvious that every
one of these calls is expected to happen.

Link: https://github.com/ClangBuiltLinux/linux/issues/1473
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Dávid Bolvanský <david.bolvansky@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014211916.3550122-1-nathan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/i915/intel_pm.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3017,9 +3017,9 @@ static void snb_wm_latency_quirk(struct
 	 * The BIOS provided WM memory latency values are often
 	 * inadequate for high resolution displays. Adjust them.
 	 */
-	changed = ilk_increase_wm_latency(dev_priv, dev_priv->wm.pri_latency, 12) |
-		ilk_increase_wm_latency(dev_priv, dev_priv->wm.spr_latency, 12) |
-		ilk_increase_wm_latency(dev_priv, dev_priv->wm.cur_latency, 12);
+	changed = ilk_increase_wm_latency(dev_priv, dev_priv->wm.pri_latency, 12);
+	changed |= ilk_increase_wm_latency(dev_priv, dev_priv->wm.spr_latency, 12);
+	changed |= ilk_increase_wm_latency(dev_priv, dev_priv->wm.cur_latency, 12);
 
 	if (!changed)
 		return;



  parent reply	other threads:[~2022-01-14  8:18 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-14  8:16 [PATCH 5.4 00/18] 5.4.172-rc1 review Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 01/18] workqueue: Fix unbind_workers() VS wq_worker_running() race Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 02/18] Bluetooth: btusb: fix memory leak in btusb_mtk_submit_wmt_recv_urb() Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 03/18] Bluetooth: bfusb: fix division by zero in send path Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 04/18] USB: core: Fix bug in resuming hubs handling of wakeup requests Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 05/18] USB: Fix "slab-out-of-bounds Write" bug in usb_hcd_poll_rh_status Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 06/18] mmc: sdhci-pci: Add PCI ID for Intel ADL Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 07/18] veth: Do not record rx queue hint in veth_xmit Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 08/18] mfd: intel-lpss: Fix too early PM enablement in the ACPI ->probe() Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 09/18] drivers core: Use sysfs_emit and sysfs_emit_at for show(device *...) functions Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 10/18] can: gs_usb: fix use of uninitialized variable, detach device on reception of invalid USB data Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 11/18] can: gs_usb: gs_can_start_xmit(): zero-initialize hf->{flags,reserved} Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 12/18] random: fix data race on crng_node_pool Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 13/18] random: fix data race on crng init time Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 14/18] random: fix crash on multiple early calls to add_bootloader_randomness() Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 15/18] media: Revert "media: uvcvideo: Set unique vdev name based in type" Greg Kroah-Hartman
2022-01-14  8:16 ` [PATCH 5.4 16/18] staging: wlan-ng: Avoid bitwise vs logical OR warning in hfa384x_usb_throttlefn() Greg Kroah-Hartman
2022-01-14  8:16 ` Greg Kroah-Hartman [this message]
2022-01-14  8:16 ` [PATCH 5.4 18/18] staging: greybus: fix stack size warning with UBSAN Greg Kroah-Hartman
2022-01-14 18:09 ` [PATCH 5.4 00/18] 5.4.172-rc1 review Jon Hunter
2022-01-14 20:15 ` Florian Fainelli
2022-01-15  0:26 ` Shuah Khan
2022-01-15  6:05 ` Naresh Kamboju
2022-01-15 11:09 ` Sudip Mukherjee
2022-01-15 16:38 ` Guenter Roeck

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