Messages in this thread Patch in this message | | | Date | Wed, 21 Dec 2016 21:07:21 -0800 | From | Jessica Yu <> | Subject | Re: kmod: provide wrappers for kmod_concurrent inc/dec |
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+++ 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 >
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