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kernel/umh.c: optimize 'proc_cap_handler()' 

If 'write' is 0, we can avoid a call to spin_lock/spin_unlock.

Link: http://lkml.kernel.org/r/20171020193331.7233-1-christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christophe JAILLET 2017-11-17 15:27:32 -08:00 committed by Linus Torvalds
parent 4ca59b14e5
commit 8c703d6604
1 changed files with 2 additions and 2 deletions
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4
kernel/umh.c
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@ -537,14 +537,14 @@ static int proc_cap_handler(struct ctl_table *table, int write,
/* /*
* Drop everything not in the new_cap (but don't add things) * Drop everything not in the new_cap (but don't add things)
*/ */
spin_lock(&umh_sysctl_lock);
if (write) { if (write) {
spin_lock(&umh_sysctl_lock);
if (table->data == CAP_BSET) if (table->data == CAP_BSET)
usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap); usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap);
if (table->data == CAP_PI) if (table->data == CAP_PI)
usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap); usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap);
}
spin_unlock(&umh_sysctl_lock); spin_unlock(&umh_sysctl_lock);
}
return 0; return 0;
} }