From: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
To: greg@kroah.com
Cc: torvalds@linux-foundation.org,
Randy Dunlap <rdunlap@xenotime.net>,
linux-kernel@vger.kernel.org,
Pekka Enberg <penberg@cs.helsinki.fi>
Subject: debugfs_create_u*() not SMP-safe
Date: Fri, 18 Jul 2008 06:52:37 +0300 [thread overview]
Message-ID: <20080718035237.GA7744@localhost> (raw)
Hi,
I noticed debugfs_create_u*() functions don't allow for any precautions
to be taken while doing r/w to the exported variables. Thus any export of a
variable isn't SMP-safe.
As far as I can tell, this only works safely for constant data. Let me
ask then, what is the purpose of these functions? Are they intended only
for unreliable data?
As I see it, they could be replaced by one of the following:
- Have them only export atomic data, that is atomic_t variables.
- Have them take a lock as a parameter, which the read() / write()
handler grabs. The kernel code that exported the variable should also
do r/w while holding that same lock.
Or am I wrong?
Thanks,
Eduard
next reply other threads:[~2008-07-18 3:54 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-18 3:52 Eduard - Gabriel Munteanu [this message]
2008-07-18 18:46 ` debugfs_create_u*() not SMP-safe Greg KH
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