From: Jessica Yu <jeyu@redhat.com>
To: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: shuah@kernel.org, rusty@rustcorp.com.au, ebiederm@xmission.com,
dmitry.torokhov@gmail.com, acme@redhat.com, corbet@lwn.net,
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,
linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: kmod: provide wrappers for kmod_concurrent inc/dec
Date: Wed, 21 Dec 2016 21:07:21 -0800 [thread overview]
Message-ID: <20161222050720.dlpdzf2vicyvv3od@jeyu> (raw)
In-Reply-To: <20161208194824.2532-1-mcgrof@kernel.org>
+++ Luis R. Rodriguez [08/12/16 11:48 -0800]:
>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 | 27 +++++++++++++++++++++------
> 1 file changed, 21 insertions(+), 6 deletions(-)
>
>diff --git a/kernel/kmod.c b/kernel/kmod.c
>index cb6f7ca7b8a5..049d7eabda38 100644
>--- a/kernel/kmod.c
>+++ b/kernel/kmod.c
>@@ -44,6 +44,9 @@
> #include <trace/events/module.h>
>
> extern int max_threads;
>+
>+static atomic_t kmod_concurrent = ATOMIC_INIT(0);
>+
> unsigned int max_modprobes;
> module_param(max_modprobes, uint, 0644);
> MODULE_PARM_DESC(max_modprobes, "Max number of allowed concurrent modprobes");
>@@ -108,6 +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)
Should this not be <=? I think this only allows up to max_modprobes-1 concurrent threads.
>+ 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
>@@ -129,7 +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;
>
> /*
>@@ -153,8 +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
>@@ -162,15 +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);
>--
>2.10.1
>
next prev parent reply other threads:[~2016-12-22 5:07 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-08 18:47 [RFC 00/10] kmod: stress test driver, few fixes and enhancements Luis R. Rodriguez
2016-12-08 18:47 ` [RFC 01/10] kmod: add test driver to stress test the module loader Luis R. Rodriguez
2016-12-08 20:24 ` Kees Cook
2016-12-13 21:10 ` Luis R. Rodriguez
2016-12-16 7:41 ` Luis R. Rodriguez
2016-12-08 19:48 ` [RFC 02/10] module: fix memory leak on early load_module() failures Luis R. Rodriguez
2016-12-08 20:30 ` Kees Cook
2016-12-08 21:10 ` Luis R. Rodriguez
2016-12-08 21:17 ` Kees Cook
2016-12-09 17:06 ` Miroslav Benes
2016-12-16 8:51 ` Luis R. Rodriguez
2016-12-15 18:46 ` Aaron Tomlin
2016-12-08 19:48 ` [RFC 03/10] kmod: add dynamic max concurrent thread count Luis R. Rodriguez
2016-12-08 20:28 ` Kees Cook
2016-12-08 21:00 ` Luis R. Rodriguez
2016-12-14 15:38 ` Petr Mladek
2016-12-16 8:39 ` Luis R. Rodriguez
2017-01-10 19:24 ` Luis R. Rodriguez
2016-12-08 19:48 ` [RFC 04/10] kmod: provide wrappers for kmod_concurrent inc/dec Luis R. Rodriguez
2016-12-08 20:29 ` Kees Cook
2016-12-08 21:08 ` Luis R. Rodriguez
2016-12-15 12:46 ` Petr Mladek
2016-12-16 8:05 ` Luis R. Rodriguez
2016-12-22 4:48 ` Jessica Yu
2017-01-06 20:54 ` Luis R. Rodriguez
2017-01-10 18:57 ` [RFC 04/10] " Luis R. Rodriguez
2017-01-11 20:08 ` Luis R. Rodriguez
2017-05-16 18:02 ` Luis R. Rodriguez
2017-05-18 2:37 ` Luis R. Rodriguez
2016-12-22 5:07 ` Jessica Yu [this message]
2017-01-10 20:28 ` Luis R. Rodriguez
2016-12-08 19:48 ` [RFC 05/10] kmod: return -EBUSY if modprobe limit is reached Luis R. Rodriguez
2016-12-08 19:48 ` [RFC 06/10] kmod: provide sanity check on kmod_concurrent access Luis R. Rodriguez
2016-12-14 16:08 ` Petr Mladek
2016-12-14 17:12 ` Luis R. Rodriguez
2016-12-15 12:57 ` Petr Mladek
2017-01-10 20:00 ` Luis R. Rodriguez
2016-12-08 19:49 ` [RFC 07/10] kmod: use simplified rate limit printk Luis R. Rodriguez
2016-12-14 16:23 ` Petr Mladek
2016-12-14 16:41 ` Joe Perches
2016-12-16 8:44 ` Luis R. Rodriguez
2016-12-08 19:49 ` [RFC 08/10] sysctl: add support for unsigned int properly Luis R. Rodriguez
2016-12-08 19:49 ` [RFC 09/10] kmod: add helpers for getting kmod count and limit Luis R. Rodriguez
2016-12-15 16:56 ` Petr Mladek
2016-12-16 7:57 ` Luis R. Rodriguez
2017-01-11 18:27 ` Luis R. Rodriguez
2016-12-08 19:49 ` [RFC 10/10] kmod: add a sanity check on module loading Luis R. Rodriguez
2016-12-09 20:03 ` Martin Wilck
2016-12-09 20:56 ` Linus Torvalds
2016-12-15 18:08 ` Luis R. Rodriguez
2016-12-15 0:27 ` Rusty Russell
2016-12-16 8:31 ` Luis R. Rodriguez
2016-12-17 3:54 ` Rusty Russell
[not found] ` <CAB=NE6VvuA9a6hf6yoopGfUxVJQM5HyV5bNzUdsEtUV0UhbG-g@mail.gmail.com>
2016-12-20 0:53 ` Rusty Russell
2016-12-20 18:52 ` Luis R. Rodriguez
2016-12-21 2:21 ` Rusty Russell
2016-12-21 13:08 ` Luis R. Rodriguez
2017-01-03 0:04 ` Rusty Russell
2017-01-06 20:36 ` Luis R. Rodriguez
2017-01-06 21:53 ` Jessica Yu
2017-01-09 20:27 ` Luis R. Rodriguez
[not found] ` <87bmvgax51.fsf@rustcorp.com.au>
2017-01-09 19:56 ` [RFC 10/10] " Luis R. Rodriguez
2017-01-06 21:03 ` Jessica Yu
2017-01-04 2:47 ` Jessica Yu
2017-01-11 19:10 ` [RFC 00/10] kmod: stress test driver, few fixes and enhancements Luis R. Rodriguez
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