From: Wolfram Sang <w.sang@pengutronix.de>
To: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Rusty Russell <rusty@rustcorp.com.au>,
Jean Delvare <khali@linux-fr.org>,
linux-i2c@vger.kernel.org, Roland Dreier <roland@kernel.org>,
Sean Hefty <sean.hefty@intel.com>,
Hal Rosenstock <hal.rosenstock@gmail.com>,
"Marciniszyn, Mike" <mike.marciniszyn@intel.com>,
Jack Morgenstein <jackm@dev.mellanox.co.il>,
Or Gerlitz <ogerlitz@mellanox.com>,
linux-rdma@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 2/6] idr: remove MAX_IDR_MASK and move left MAX_IDR_* into idr.c
Date: Sun, 10 Feb 2013 12:52:14 +0100 [thread overview]
Message-ID: <20130210115214.GC5472@nekote.pengutronix.de> (raw)
In-Reply-To: <20130208210149.GB26660@mtj.dyndns.org>
On Fri, Feb 08, 2013 at 01:01:49PM -0800, Tejun Heo wrote:
> MAX_IDR_MASK is another weirdness in the idr interface. As idr covers
> whole positive integer range, it's defined as 0x7fffffff or INT_MAX.
>
> Its usage in idr_find(), idr_replace() and idr_remove() is bizarre.
> They basically mask off the sign bit and operate on the rest, so if
> the caller, by accident, passes in a negative number, the sign bit
> will be masked off and the remaining part will be used as if that was
> the input, which is worse than crashing.
>
> The constant is visible in idr.h and there are several users in the
> kernel.
>
> * drivers/i2c/i2c-core.c:i2c_add_numbered_adapter()
>
> Basically used to test if adap->nr is a negative number which isn't
> -1 and returns -EINVAL if so. idr_alloc() already has negative
> @start checking (w/ WARN_ON_ONCE), so this can go away.
>
> * drivers/infiniband/core/cm.c:cm_alloc_id()
> drivers/infiniband/hw/mlx4/cm.c:id_map_alloc()
>
> Used to wrap cyclic @start. Can be replaced with max(next, 0).
> Note that this type of cyclic allocation using idr is buggy. These
> are prone to spurious -ENOSPC failure after the first wraparound.
>
> * fs/super.c:get_anon_bdev()
>
> The ID allocated from ida is masked off before being tested whether
> it's inside valid range. ida allocated ID can never be a negative
> number and the masking is unnecessary.
>
> Update idr_*() functions to fail with -EINVAL when negative @id is
> specified and update other MAX_IDR_MASK users as described above.
>
> This leaves MAX_IDR_MASK without any user, remove it and relocate
> other MAX_IDR_* constants to lib/idr.c.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
For the i2c-part:
Acked-by: Wolfram Sang <wolfram@the-dreams.de>
next prev parent reply other threads:[~2013-02-10 11:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-08 21:00 [PATCH 1/6] idr: fix top layer handling Tejun Heo
2013-02-08 21:01 ` [PATCH 2/6] idr: remove MAX_IDR_MASK and move left MAX_IDR_* into idr.c Tejun Heo
2013-02-08 22:09 ` Hefty, Sean
2013-02-09 19:00 ` Tejun Heo
2013-02-10 21:19 ` Hefty, Sean
2013-02-10 11:52 ` Wolfram Sang [this message]
2013-02-08 21:02 ` [PATCH 3/6] idr: remove length restriction from idr_layer->bitmap Tejun Heo
2013-02-08 21:03 ` [PATCH 4/6] idr: make idr_layer larger Tejun Heo
2013-02-08 21:03 ` [PATCH 5/6] idr: add idr_layer->prefix Tejun Heo
2013-02-08 21:03 ` [PATCH 6/6] idr: implement lookup hint Tejun Heo
2013-02-11 23:39 ` [PATCH 1/6] idr: fix top layer handling Andrew Morton
2013-02-12 17:10 ` Tejun Heo
2013-02-12 21:23 ` Andrew Morton
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