/* Helper functions for Thinkpad LED control;
 * to be included from codec driver
 */

#if IS_ENABLED(CONFIG_THINKPAD_ACPI)

#include <linux/acpi.h>
#include <linux/thinkpad_acpi.h>

static int (*led_set_func)(int, bool);
static void (*old_vmaster_hook)(void *, int);

static bool is_thinkpad(struct hda_codec *codec)
{
	return (codec->core.subsystem_id >> 16 == 0x17aa) &&
	       (acpi_dev_found("LEN0068") || acpi_dev_found("LEN0268") ||
		acpi_dev_found("IBM0068"));
}

static void update_tpacpi_mute_led(void *private_data, int enabled)
{
	if (old_vmaster_hook)
		old_vmaster_hook(private_data, enabled);

	if (led_set_func)
		led_set_func(TPACPI_LED_MUTE, !enabled);
}

static void update_tpacpi_micmute_led(struct hda_codec *codec,
				      struct snd_kcontrol *kcontrol,
				      struct snd_ctl_elem_value *ucontrol)
{
	if (!ucontrol || !led_set_func)
		return;
	if (strcmp("Capture Switch", ucontrol->id.name) == 0 && ucontrol->id.index == 0) {
		/* TODO: How do I verify if it's a mono or stereo here? */
		bool val = ucontrol->value.integer.value[0] || ucontrol->value.integer.value[1];
		led_set_func(TPACPI_LED_MICMUTE, !val);
	}
}

static void hda_fixup_thinkpad_acpi(struct hda_codec *codec,
				    const struct hda_fixup *fix, int action)
{
	struct hda_gen_spec *spec = codec->spec;
	bool removefunc = false;

	if (action == HDA_FIXUP_ACT_PROBE) {
		if (!is_thinkpad(codec))
			return;
		if (!led_set_func)
			led_set_func = symbol_request(tpacpi_led_set);
		if (!led_set_func) {
			codec_warn(codec,
				   "Failed to find thinkpad-acpi symbol tpacpi_led_set\n");
			return;
		}

		removefunc = true;
		if (led_set_func(TPACPI_LED_MUTE, false) >= 0) {
			old_vmaster_hook = spec->vmaster_mute.hook;
			spec->vmaster_mute.hook = update_tpacpi_mute_led;
			removefunc = false;
		}
		if (led_set_func(TPACPI_LED_MICMUTE, false) >= 0) {
			if (spec->num_adc_nids > 1 && !spec->dyn_adc_switch)
				codec_dbg(codec,
					  "Skipping micmute LED control due to several ADCs");
			else {
				spec->cap_sync_hook = update_tpacpi_micmute_led;
				removefunc = false;
			}
		}
	}

	if (led_set_func && (action == HDA_FIXUP_ACT_FREE || removefunc)) {
		symbol_put(tpacpi_led_set);
		led_set_func = NULL;
		old_vmaster_hook = NULL;
	}
}

#else /* CONFIG_THINKPAD_ACPI */

static void hda_fixup_thinkpad_acpi(struct hda_codec *codec,
				    const struct hda_fixup *fix, int action)
{
}

#endif /* CONFIG_THINKPAD_ACPI */
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=3895dbf8985f656675b5bde610723a29cbce3fa7'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?id=3895dbf8985f656675b5bde610723a29cbce3fa7'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/irda?id=3895dbf8985f656675b5bde610723a29cbce3fa7'>irda</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='3895dbf8985f656675b5bde610723a29cbce3fa7'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Eric W. Biederman &lt;ebiederm@xmission.com&gt;</td><td class='right'>2017-01-03 14:18:43 +1300</td></tr>
<tr><th>committer</th><td>Eric W. Biederman &lt;ebiederm@xmission.com&gt;</td><td class='right'>2017-01-10 13:34:43 +1300</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/irda?id=3895dbf8985f656675b5bde610723a29cbce3fa7'>3895dbf8985f656675b5bde610723a29cbce3fa7</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/irda?id=3895dbf8985f656675b5bde610723a29cbce3fa7'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=3895dbf8985f656675b5bde610723a29cbce3fa7'>91d4517f09918fd573998eb40b8f35f08ed1c470</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/irda?id=3895dbf8985f656675b5bde610723a29cbce3fa7'>net/irda</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/irda?id=0c744ea4f77d72b3dcebb7a8f2684633ec79be88'>0c744ea4f77d72b3dcebb7a8f2684633ec79be88</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/irda?id=3895dbf8985f656675b5bde610723a29cbce3fa7&amp;id2=0c744ea4f77d72b3dcebb7a8f2684633ec79be88'>diff</a>)</td></tr></table>
<div class='commit-subject'>mnt: Protect the mountpoint hashtable with mount_lock</div><div class='commit-msg'>Protecting the mountpoint hashtable with namespace_sem was sufficient
until a call to umount_mnt was added to mntput_no_expire.  At which
point it became possible for multiple calls of put_mountpoint on
the same hash chain to happen on the same time.

Kristen Johansen &lt;kjlx@templeofstupid.com&gt; reported:
&gt; This can cause a panic when simultaneous callers of put_mountpoint
&gt; attempt to free the same mountpoint.  This occurs because some callers
&gt; hold the mount_hash_lock, while others hold the namespace lock.  Some
&gt; even hold both.
&gt;
&gt; In this submitter's case, the panic manifested itself as a GP fault in
&gt; put_mountpoint() when it called hlist_del() and attempted to dereference
&gt; a m_hash.pprev that had been poisioned by another thread.

Al Viro observed that the simple fix is to switch from using the namespace_sem
to the mount_lock to protect the mountpoint hash table.

I have taken Al's suggested patch moved put_mountpoint in pivot_root
(instead of taking mount_lock an additional time), and have replaced
new_mountpoint with get_mountpoint a function that does the hash table
lookup and addition under the mount_lock.   The introduction of get_mounptoint
ensures that only the mount_lock is needed to manipulate the mountpoint
hashtable.

d_set_mounted is modified to only set DCACHE_MOUNTED if it is not
already set.  This allows get_mountpoint to use the setting of
DCACHE_MOUNTED to ensure adding a struct mountpoint for a dentry
happens exactly once.

Cc: stable@vger.kernel.org
Fixes: ce07d891a089 ("mnt: Honor MNT_LOCKED when detaching mounts")
Reported-by: Krister Johansen &lt;kjlx@templeofstupid.com&gt;
Suggested-by: Al Viro &lt;viro@ZenIV.linux.org.uk&gt;
Acked-by: Al Viro &lt;viro@ZenIV.linux.org.uk&gt;
Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=3895dbf8985f656675b5bde610723a29cbce3fa7'>Diffstat</a> (limited to 'net/irda')</div><table summary='diffstat' class='diffstat'>