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From:   "M. Vefa Bicakci" <m.v.b@runbox.com>
To:     platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com>,
        Vishwanath Somayaji <vishwanath.somayaji@intel.com>,
        Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        "M. Vefa Bicakci" <m.v.b@runbox.com>
Subject: [PATCH] platform/x86: intel_pmc_core_pltdrv: Module removal warning fix
Date:   Thu, 15 Aug 2019 21:41:40 -0400
Message-Id: <20190816014140.10687-2-m.v.b@runbox.com>
In-Reply-To: <20190816014140.10687-1-m.v.b@runbox.com>
References: <20190816014140.10687-1-m.v.b@runbox.com>
MIME-Version: 1.0
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Sender: linux-kernel-owner@vger.kernel.org
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Prior to this commit, removing the intel_pmc_core_pltdrv module
would cause the following warning:

  ------------[ cut here ]------------
  Device 'intel_pmc_core.0' does not have a release() function, \
    it is broken and must be fixed. See Documentation/kobject.txt.
  WARNING: CPU: 0 PID: 2202 at drivers/base/core.c:1238 device_release+0x6f/0x80
  Modules linked in: fuse intel_rapl_msr ip6table_filter ip6_tables ipt_REJECT \
    nf_reject_ipv4 xt_conntrack iptable_filter xt_MASQUERADE iptable_nat nf_nat \
    nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c intel_rapl_common \
    intel_pmc_core_pltdrv(-) xen_netfront intel_pmc_core crct10dif_pclmul \
    crc32_pclmul crc32c_intel ghash_clmulni_intel intel_rapl_perf pcspkr binfmt_misc \
    u2mfn(O) xenfs xen_gntdev xen_gntalloc xen_blkback xen_privcmd xen_evtchn \
    ip_tables overlay xen_blkfront
  CPU: 0 PID: 2202 Comm: rmmod Tainted: G        W  O      5.3.0-rc3-next-20190809-1 #2
  RIP: 0010:device_release+0x6f/0x80
  Code: 48 8b 85 c0 02 00 00 48 85 c0 74 09 48 8b 40 40 48 85 c0 75 c6 48 8b 75 50 48 85 f6 74 10 48 c7 c7 58 68 12 82 e8 5f 62 a9 ff <0f> 0b eb b5 48 8b 75 00 eb ea 0f 1f 80 00 00 00 00 0f 1f 44 00 00
  RSP: 0018:ffffc90000763ea8 EFLAGS: 00010286
  RAX: 0000000000000000 RBX: ffffffff822da080 RCX: 0000000000000006
  RDX: 0000000000000007 RSI: 0000000000000082 RDI: ffff88813ba17540
  RBP: ffffffffc0107010 R08: 0000000000000195 R09: 000000000000000d
  R10: 000000000000000a R11: ffffc90000763d65 R12: ffff88800c9e9000
  R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
  FS:  000071250bf142c0(0000) GS:ffff88813ba00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 000060ab8fd82d49 CR3: 00000001273ba004 CR4: 00000000003606f0
  Call Trace:
   kobject_put+0x85/0x1b0
   __x64_sys_delete_module+0x14b/0x270
   do_syscall_64+0x5f/0x1a0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x71250c031c6b
  Code: 73 01 c3 48 8b 0d 1d 42 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ed 41 0c 00 f7 d8 64 89 01 48
  RSP: 002b:00007ffec29e6038 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
  RAX: ffffffffffffffda RBX: 00006040bc3e07b0 RCX: 000071250c031c6b
  RDX: 000000000000000a RSI: 0000000000000800 RDI: 00006040bc3e0818
  RBP: 00007ffec29e6088 R08: 1999999999999999 R09: 0000000000000000
  R10: 000071250c0a6ac0 R11: 0000000000000206 R12: 00007ffec29e6250
  R13: 00007ffec29e67b7 R14: 00006040bc3e0260 R15: 00007ffec29e6090
  ---[ end trace 5e5421608729d6f5 ]---

This commit hence adds an empty release function for the driver.

Signed-off-by: M. Vefa Bicakci <m.v.b@runbox.com>
---
 drivers/platform/x86/intel_pmc_core_pltdrv.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/platform/x86/intel_pmc_core_pltdrv.c b/drivers/platform/x86/intel_pmc_core_pltdrv.c
index a8754a6db1b8..186540014c48 100644
--- a/drivers/platform/x86/intel_pmc_core_pltdrv.c
+++ b/drivers/platform/x86/intel_pmc_core_pltdrv.c
@@ -18,8 +18,16 @@
 #include <asm/cpu_device_id.h>
 #include <asm/intel-family.h>
 
+static void intel_pmc_core_release(struct device *dev)
+{
+	/* Nothing to do. */
+}
+
 static struct platform_device pmc_core_device = {
 	.name = "intel_pmc_core",
+	.dev  = {
+		.release = intel_pmc_core_release,
+	},
 };
 
 /*
-- 
2.21.0