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From: "Luis R. Rodriguez" <mcgrof@kernel.org>
To: shuah@kernel.org, jeyu@redhat.com, rusty@rustcorp.com.au,
	ebiederm@xmission.com, dmitry.torokhov@gmail.com,
	acme@redhat.com, corbet@lwn.net
Cc: martin.wilck@suse.com, mmarek@suse.com, pmladek@suse.com,
	hare@suse.com, rwright@hpe.com, jeffm@suse.com, DSterba@suse.com,
	fdmanana@suse.com, neilb@suse.com, linux@roeck-us.net,
	rgoldwyn@suse.com, subashab@codeaurora.org, xypron.glpk@gmx.de,
	keescook@chromium.org, atomlin@redhat.com, mbenes@suse.cz,
	paulmck@linux.vnet.ibm.com, dan.j.williams@intel.com,
	jpoimboe@redhat.com, davem@davemloft.net, mingo@redhat.com,
	akpm@linux-foundation.org, torvalds@linux-foundation.org,
	gregkh@linuxfoundation.org, linux-kselftest@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Luis R. Rodriguez" <mcgrof@kernel.org>
Subject: [PATCH 3/6] kmod: provide wrappers for kmod_concurrent inc/dec
Date: Thu, 18 May 2017 20:24:41 -0700
Message-ID: <20170519032444.18416-4-mcgrof@kernel.org> (raw)
In-Reply-To: <20170519032444.18416-1-mcgrof@kernel.org>

kmod_concurrent is used as an atomic counter for enabling
the allowed limit of modprobe calls, provide wrappers for it
to enable this to be expanded on more easily. This will be done
later.

Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
---
 kernel/kmod.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 6fe6848787b2..7635915dc91c 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -59,6 +59,7 @@ static DEFINE_SPINLOCK(umh_sysctl_lock);
 static DECLARE_RWSEM(umhelper_sem);
 
 #ifdef CONFIG_MODULES
+static atomic_t kmod_concurrent = ATOMIC_INIT(0);
 
 /*
 	modprobe_path is set via /proc/sys.
@@ -110,6 +111,20 @@ static int call_modprobe(char *module_name, int wait)
 	return -ENOMEM;
 }
 
+static int kmod_umh_threads_get(void)
+{
+	atomic_inc(&kmod_concurrent);
+	if (atomic_read(&kmod_concurrent) <= max_modprobes)
+		return 0;
+	atomic_dec(&kmod_concurrent);
+	return -ENOMEM;
+}
+
+static void kmod_umh_threads_put(void)
+{
+	atomic_dec(&kmod_concurrent);
+}
+
 /**
  * __request_module - try to load a kernel module
  * @wait: wait (or not) for the operation to complete
@@ -131,7 +146,6 @@ int __request_module(bool wait, const char *fmt, ...)
 	va_list args;
 	char module_name[MODULE_NAME_LEN];
 	int ret;
-	static atomic_t kmod_concurrent = ATOMIC_INIT(0);
 	static int kmod_loop_msg;
 
 	/*
@@ -155,8 +169,8 @@ int __request_module(bool wait, const char *fmt, ...)
 	if (ret)
 		return ret;
 
-	atomic_inc(&kmod_concurrent);
-	if (atomic_read(&kmod_concurrent) > max_modprobes) {
+	ret = kmod_umh_threads_get();
+	if (ret) {
 		/* We may be blaming an innocent here, but unlikely */
 		if (kmod_loop_msg < 5) {
 			printk(KERN_ERR
@@ -164,15 +178,14 @@ int __request_module(bool wait, const char *fmt, ...)
 			       module_name);
 			kmod_loop_msg++;
 		}
-		atomic_dec(&kmod_concurrent);
-		return -ENOMEM;
+		return ret;
 	}
 
 	trace_module_request(module_name, wait, _RET_IP_);
 
 	ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
 
-	atomic_dec(&kmod_concurrent);
+	kmod_umh_threads_put();
 	return ret;
 }
 EXPORT_SYMBOL(__request_module);
-- 
2.11.0

  parent reply index

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-19  3:24 [PATCH 0/6] kmod: few simple enhancements Luis R. Rodriguez
2017-05-19  3:24 ` [PATCH 1/6] kmod: add dynamic max concurrent thread count Luis R. Rodriguez
2017-05-19 20:44   ` Dmitry Torokhov
     [not found]     ` <CAB=NE6XGL24O+JfTNUG0HO4obhDc-v+HyL0SCrQELiZrj2-qNw@mail.gmail.com>
     [not found]       ` <CAB=NE6Wa4Nemh80yaCCwbjrNRLPD+GJMncg12APg9Vq63AWVng@mail.gmail.com>
     [not found]         ` <CAB=NE6Vc6RDAytn2Pkv2V58HFo8ncR0eOHZ3===kbZ2NF78ubg@mail.gmail.com>
     [not found]           ` <CAB=NE6Vqmx=y6muenpuQKynTP=pGWMF8tzoCA0BXD6d63q9wPg@mail.gmail.com>
2017-05-19 21:58             ` Dmitry Torokhov
2017-05-25 16:22               ` Luis R. Rodriguez
2017-05-25 16:38                 ` Dmitry Torokhov
2017-05-25 16:50                   ` Luis R. Rodriguez
2017-05-25 17:30                     ` Dmitry Torokhov
2017-05-25 17:38                       ` Luis R. Rodriguez
2017-05-25 18:06                         ` Luis R. Rodriguez
2017-05-25 18:26                           ` Dmitry Torokhov
2017-05-25 19:01                             ` Luis R. Rodriguez
2017-05-25 21:38                               ` Luis R. Rodriguez
2017-05-19  3:24 ` [PATCH 2/6] module: use list_for_each_entry_rcu() on find_module_all() Luis R. Rodriguez
2017-05-23 14:46   ` Miroslav Benes
2017-05-19  3:24 ` Luis R. Rodriguez [this message]
2017-05-19  3:24 ` [PATCH 4/6] kmod: return -EBUSY if modprobe limit is reached Luis R. Rodriguez
2017-05-19  3:24 ` [PATCH 5/6] kmod: preempt on kmod_umh_threads_get() Luis R. Rodriguez
2017-05-19 22:27   ` Dmitry Torokhov
2017-05-25  0:14     ` Luis R. Rodriguez
2017-05-25  0:45       ` Dmitry Torokhov
2017-05-25  1:00         ` Luis R. Rodriguez
2017-05-25  2:27           ` Dmitry Torokhov
2017-05-25 11:19             ` Petr Mladek
2017-05-25 15:38               ` Luis R. Rodriguez
2017-05-25 16:42               ` Dmitry Torokhov
2017-05-25 15:18             ` Jessica Yu
2017-05-19  3:24 ` [PATCH 6/6] kmod: use simplified rate limit printk Luis R. Rodriguez
2017-05-19 22:23   ` Dmitry Torokhov
2017-05-23  9:00     ` Petr Mladek
2017-05-26  0:16 ` [PATCH v2 0/5] kmod: help make deterministic Luis R. Rodriguez
2017-05-26  0:16   ` [PATCH v2 1/5] module: use list_for_each_entry_rcu() on find_module_all() Luis R. Rodriguez
2017-05-26  0:16   ` [PATCH v2 2/5] kmod: reduce atomic operations on kmod_concurrent Luis R. Rodriguez
2017-05-26  1:11     ` Dmitry Torokhov
2017-05-26 20:03       ` Luis R. Rodriguez
2017-05-26  0:16   ` [PATCH v2 3/5] kmod: add test driver to stress test the module loader Luis R. Rodriguez
2017-05-26  0:16   ` [PATCH v2 4/5] kmod: add helpers for getting kmod limit Luis R. Rodriguez
2017-05-26  0:56     ` Dmitry Torokhov
2017-05-26 20:27       ` Luis R. Rodriguez
2017-05-26  0:16   ` [PATCH v2 5/5] kmod: throttle kmod thread limit Luis R. Rodriguez
2017-05-26 21:12   ` [PATCH v3 0/4] kmod: help make deterministic Luis R. Rodriguez
2017-05-26 21:12     ` [PATCH v3 1/4] module: use list_for_each_entry_rcu() on find_module_all() Luis R. Rodriguez
2017-05-26 21:12     ` [PATCH v3 2/4] kmod: reduce atomic operations on kmod_concurrent and simplify Luis R. Rodriguez
2017-06-23 19:19       ` [PATCH v4 " Luis R. Rodriguez
2017-06-26 11:36       ` [PATCH v3 " Petr Mladek
2017-05-26 21:12     ` [PATCH v3 3/4] kmod: add test driver to stress test the module loader Luis R. Rodriguez
2017-05-26 21:12     ` [PATCH v3 4/4] kmod: throttle kmod thread limit Luis R. Rodriguez
2017-06-22 15:19       ` Petr Mladek
2017-06-23 16:16         ` Luis R. Rodriguez
2017-06-23 17:56           ` Luis R. Rodriguez
2017-06-23 19:16             ` Luis R. Rodriguez
2017-06-26 10:03               ` Petr Mladek
2017-06-26  9:55           ` Petr Mladek
2017-06-23 19:20       ` [PATCH v4 " Luis R. Rodriguez
2017-06-26 11:38         ` Petr Mladek
2017-06-28 22:11           ` Luis R. Rodriguez
2017-06-20 20:56     ` [PATCH v3 0/4] kmod: help make deterministic Luis R. Rodriguez
2017-06-21  0:23       ` Kees Cook
2017-06-26 21:37         ` Jessica Yu
2017-06-26 22:44           ` Luis R. Rodriguez
2017-06-27  0:27             ` Luis R. Rodriguez
2017-06-27  8:13               ` Petr Mladek
2017-06-27 10:04                 ` Jessica Yu
2017-06-27 15:26             ` Jessica Yu
2017-06-28  0:49               ` Luis R. Rodriguez
2017-06-28 22:31     ` [PATCH v4 0/3] " Luis R. Rodriguez
2017-06-28 22:31       ` [PATCH v4 1/3] MAINTAINERS: give kmod some maintainer love Luis R. Rodriguez
2017-06-28 22:31       ` [PATCH v4 2/3] kmod: add test driver to stress test the module loader Luis R. Rodriguez
2017-06-28 22:31       ` [PATCH v4 3/3] kmod: throttle kmod thread limit Luis R. Rodriguez

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