/*
 * linux/fs/nfs/cache_lib.c
 *
 * Helper routines for the NFS client caches
 *
 * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
 */
#include <linux/kmod.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/slab.h>
#include <linux/sunrpc/cache.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <net/net_namespace.h>

#include "cache_lib.h"

#define NFS_CACHE_UPCALL_PATHLEN 256
#define NFS_CACHE_UPCALL_TIMEOUT 15

static char nfs_cache_getent_prog[NFS_CACHE_UPCALL_PATHLEN] =
				"/sbin/nfs_cache_getent";
static unsigned long nfs_cache_getent_timeout = NFS_CACHE_UPCALL_TIMEOUT;

module_param_string(cache_getent, nfs_cache_getent_prog,
		sizeof(nfs_cache_getent_prog), 0600);
MODULE_PARM_DESC(cache_getent, "Path to the client cache upcall program");
module_param_named(cache_getent_timeout, nfs_cache_getent_timeout, ulong, 0600);
MODULE_PARM_DESC(cache_getent_timeout, "Timeout (in seconds) after which "
		"the cache upcall is assumed to have failed");

int nfs_cache_upcall(struct cache_detail *cd, char *entry_name)
{
	static char *envp[] = { "HOME=/",
		"TERM=linux",
		"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
		NULL
	};
	char *argv[] = {
		nfs_cache_getent_prog,
		cd->name,
		entry_name,
		NULL
	};
	int ret = -EACCES;

	if (nfs_cache_getent_prog[0] == '\0')
		goto out;
	ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
	/*
	 * Disable the upcall mechanism if we're getting an ENOENT or
	 * EACCES error. The admin can re-enable it on the fly by using
	 * sysfs to set the 'cache_getent' parameter once the problem
	 * has been fixed.
	 */
	if (ret == -ENOENT || ret == -EACCES)
		nfs_cache_getent_prog[0] = '\0';
out:
	return ret > 0 ? 0 : ret;
}

/*
 * Deferred request handling
 */
void nfs_cache_defer_req_put(struct nfs_cache_defer_req *dreq)
{
	if (atomic_dec_and_test(&dreq->count))
		kfree(dreq);
}

static void nfs_dns_cache_revisit(struct cache_deferred_req *d, int toomany)
{
	struct nfs_cache_defer_req *dreq;

	dreq = container_of(d, struct nfs_cache_defer_req, deferred_req);

	complete(&dreq->completion);
	nfs_cache_defer_req_put(dreq);
}

static struct cache_deferred_req *nfs_dns_cache_defer(struct cache_req *req)
{
	struct nfs_cache_defer_req *dreq;

	dreq = container_of(req, struct nfs_cache_defer_req, req);
	dreq->deferred_req.revisit = nfs_dns_cache_revisit;
	atomic_inc(&dreq->count);

	return &dreq->deferred_req;
}

struct nfs_cache_defer_req *nfs_cache_defer_req_alloc(void)
{
	struct nfs_cache_defer_req *dreq;

	dreq = kzalloc(sizeof(*dreq), GFP_KERNEL);
	if (dreq) {
		init_completion(&dreq->completion);
		atomic_set(&dreq->count, 1);
		dreq->req.defer = nfs_dns_cache_defer;
	}
	return dreq;
}

int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq)
{
	if (wait_for_completion_timeout(&dreq->completion,
			nfs_cache_getent_timeout * HZ) == 0)
		return -ETIMEDOUT;
	return 0;
}

int nfs_cache_register_sb(struct super_block *sb, struct cache_detail *cd)
{
	int ret;
	struct dentry *dir;

	dir = rpc_d_lookup_sb(sb, "cache");
	ret = sunrpc_cache_register_pipefs(dir, cd->name, 0600, cd);
	dput(dir);
	return ret;
}

int nfs_cache_register_net(struct net *net, struct cache_detail *cd)
{
	struct super_block *pipefs_sb;
	int ret = 0;

	sunrpc_init_cache_detail(cd);
	pipefs_sb = rpc_get_sb_net(net);
	if (pipefs_sb) {
		ret = nfs_cache_register_sb(pipefs_sb, cd);
		rpc_put_sb_net(net);
		if (ret)
			sunrpc_destroy_cache_detail(cd);
	}
	return ret;
}

void nfs_cache_unregister_sb(struct super_block *sb, struct cache_detail *cd)
{
	if (cd->u.pipefs.dir)
		sunrpc_cache_unregister_pipefs(cd);
}

void nfs_cache_unregister_net(struct net *net, struct cache_detail *cd)
{
	struct super_block *pipefs_sb;

	pipefs_sb = rpc_get_sb_net(net);
	if (pipefs_sb) {
		nfs_cache_unregister_sb(pipefs_sb, cd);
		rpc_put_sb_net(net);
	}
	sunrpc_destroy_cache_detail(cd);
}
0</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>Marc Zyngier &lt;marc.zyngier@arm.com&gt;</td><td class='right'>2017-01-17 16:00:48 +0000</td></tr>
<tr><th>committer</th><td>Thomas Gleixner &lt;tglx@linutronix.de&gt;</td><td class='right'>2017-01-30 15:18:56 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/uapi/sound/Kbuild?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>08d85f3ea99f1eeafc4e8507936190e86a16ee8c</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/uapi/sound/Kbuild?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>410bb1acd0cd7dcfaad37ae7b63ff243b7fa4bee</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/uapi/sound/Kbuild?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>include/uapi/sound/Kbuild</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/uapi/sound/Kbuild?id=566cf877a1fcb6d6dc0126b076aad062054c2637'>566cf877a1fcb6d6dc0126b076aad062054c2637</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/uapi/sound/Kbuild?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c&amp;id2=566cf877a1fcb6d6dc0126b076aad062054c2637'>diff</a>)</td></tr></table>
<div class='commit-subject'>irqdomain: Avoid activating interrupts more than once</div><div class='commit-msg'>Since commit f3b0946d629c ("genirq/msi: Make sure PCI MSIs are
activated early"), we can end-up activating a PCI/MSI twice (once
at allocation time, and once at startup time).

This is normally of no consequences, except that there is some
HW out there that may misbehave if activate is used more than once
(the GICv3 ITS, for example, uses the activate callback
to issue the MAPVI command, and the architecture spec says that
"If there is an existing mapping for the EventID-DeviceID
combination, behavior is UNPREDICTABLE").

While this could be worked around in each individual driver, it may
make more sense to tackle the issue at the core level. In order to
avoid getting in that situation, let's have a per-interrupt flag
to remember if we have already activated that interrupt or not.

Fixes: f3b0946d629c ("genirq/msi: Make sure PCI MSIs are activated early")
Reported-and-tested-by: Andre Przywara &lt;andre.przywara@arm.com&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1484668848-24361-1-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=08d85f3ea99f1eeafc4e8507936190e86a16ee8c'>Diffstat</a> (limited to 'include/uapi/sound/Kbuild')</div><table summary='diffstat' class='diffstat'>