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From: Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
To: Ohad Ben-Cohen <ohad-Ix1uc/W3ht7QT0dZR+AlfA@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	"Jean Delvare (PC drivers,
	core)" <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>,
	"Ben Dooks (embedded platforms)"
	<ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>,
	Roland Dreier <rolandd-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>,
	Sean Hefty <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Hal Rosenstock
	<hal.rosenstock-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Steve Wise <swise-ut6Up61K2wZBDgjK7y7TUQ@public.gmane.org>,
	Neil Brown <neilb-l3A5Bk7waGM@public.gmane.org>,
	Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-ppp-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org
Subject: Re: idr_get_new_exact ?
Date: Mon, 20 Sep 2010 13:35:42 -0700	[thread overview]
Message-ID: <adaiq20f90h.fsf@cisco.com> (raw)
In-Reply-To: <AANLkTi=ZLupVyFR0e2v-TLpeNWdw1bVMZUAhgyxLJ7OV-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> (Ohad Ben-Cohen's message of "Mon, 20 Sep 2010 16:11:31 +0200")

 > Occasionally, drivers care about the value that idr associates with
 > their pointers.
 > 
 > Today we have idr_get_new_above() which allocates a new idr entry
 > above or equal to a given starting id, but sometimes drivers need to
 > force an exact value.
 > 
 > To overcome this small API gap, drivers are wrapping idr_get_new_above
 > and then either BUG_ON() or just call idr_remove() and returns -EBUSY
 > when idr allocates them an id which is different than their requested
 > value.

Looks fine to me as an improvement over the status quo, but I wonder how
many of these places could use the radix_tree stuff instead?  If you're
not using the ability of the idr code to assign an id for you, then it
seems the radix_tree API is a better fit.

 - R.

WARNING: multiple messages have this Message-ID (diff)
From: Roland Dreier <rdreier@cisco.com>
To: Ohad Ben-Cohen <ohad-Ix1uc/W3ht7QT0dZR+AlfA@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	"Jean Delvare (PC drivers,
	core)" <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>,
	"Ben Dooks (embedded platforms)"
	<ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>,
	Roland Dreier <rolandd-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>,
	Sean Hefty <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Hal Rosenstock
	<hal.rosenstock-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Steve Wise <swise-ut6Up61K2wZBDgjK7y7TUQ@public.gmane.org>,
	Neil Brown <neilb-l3A5Bk7waGM@public.gmane.org>,
	Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-ppp-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org
Subject: Re: idr_get_new_exact ?
Date: Mon, 20 Sep 2010 20:35:42 +0000	[thread overview]
Message-ID: <adaiq20f90h.fsf@cisco.com> (raw)
In-Reply-To: <AANLkTi=ZLupVyFR0e2v-TLpeNWdw1bVMZUAhgyxLJ7OV-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> (Ohad Ben-Cohen's message of "Mon, 20 Sep 2010 16:11:31 +0200")

 > Occasionally, drivers care about the value that idr associates with
 > their pointers.
 > 
 > Today we have idr_get_new_above() which allocates a new idr entry
 > above or equal to a given starting id, but sometimes drivers need to
 > force an exact value.
 > 
 > To overcome this small API gap, drivers are wrapping idr_get_new_above
 > and then either BUG_ON() or just call idr_remove() and returns -EBUSY
 > when idr allocates them an id which is different than their requested
 > value.

Looks fine to me as an improvement over the status quo, but I wonder how
many of these places could use the radix_tree stuff instead?  If you're
not using the ability of the idr code to assign an id for you, then it
seems the radix_tree API is a better fit.

 - R.

WARNING: multiple messages have this Message-ID (diff)
From: Roland Dreier <rdreier@cisco.com>
To: Ohad Ben-Cohen <ohad@wizery.com>
Cc: linux-kernel@vger.kernel.org, "Jean Delvare \(PC drivers\,
	core\)" <khali@linux-fr.org>,
	"Ben Dooks \(embedded platforms\)" <ben-linux@fluff.org>,
	Roland Dreier <rolandd@cisco.com>,
	Sean Hefty <sean.hefty@intel.com>,
	Hal Rosenstock <hal.rosenstock@gmail.com>,
	Steve Wise <swise@chelsio.com>, Neil Brown <neilb@suse.de>,
	Paul Mackerras <paulus@samba.org>,
	linux-i2c@vger.kernel.org, linux-rdma@vger.kernel.org,
	dm-devel@redhat.com, linux-raid@vger.kernel.org,
	linux-ppp@vger.kernel.org, netdev@vger.kernel.org,
	akpm@linux-foundation.org
Subject: Re: idr_get_new_exact ?
Date: Mon, 20 Sep 2010 13:35:42 -0700	[thread overview]
Message-ID: <adaiq20f90h.fsf@cisco.com> (raw)
In-Reply-To: <AANLkTi=ZLupVyFR0e2v-TLpeNWdw1bVMZUAhgyxLJ7OV@mail.gmail.com> (Ohad Ben-Cohen's message of "Mon, 20 Sep 2010 16:11:31 +0200")

 > Occasionally, drivers care about the value that idr associates with
 > their pointers.
 > 
 > Today we have idr_get_new_above() which allocates a new idr entry
 > above or equal to a given starting id, but sometimes drivers need to
 > force an exact value.
 > 
 > To overcome this small API gap, drivers are wrapping idr_get_new_above
 > and then either BUG_ON() or just call idr_remove() and returns -EBUSY
 > when idr allocates them an id which is different than their requested
 > value.

Looks fine to me as an improvement over the status quo, but I wonder how
many of these places could use the radix_tree stuff instead?  If you're
not using the ability of the idr code to assign an id for you, then it
seems the radix_tree API is a better fit.

 - R.

WARNING: multiple messages have this Message-ID (diff)
From: Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
To: Ohad Ben-Cohen <ohad-Ix1uc/W3ht7QT0dZR+AlfA@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	"Jean Delvare \(PC drivers\,
	core\)" <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>,
	"Ben Dooks \(embedded platforms\)"
	<ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>,
	Roland Dreier <rolandd-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>,
	Sean Hefty <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Hal Rosenstock
	<hal.rosenstock-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Steve Wise <swise-ut6Up61K2wZBDgjK7y7TUQ@public.gmane.org>,
	Neil Brown <neilb-l3A5Bk7waGM@public.gmane.org>,
	Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-ppp-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org
Subject: Re: idr_get_new_exact ?
Date: Mon, 20 Sep 2010 13:35:42 -0700	[thread overview]
Message-ID: <adaiq20f90h.fsf@cisco.com> (raw)
In-Reply-To: <AANLkTi=ZLupVyFR0e2v-TLpeNWdw1bVMZUAhgyxLJ7OV-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> (Ohad Ben-Cohen's message of "Mon, 20 Sep 2010 16:11:31 +0200")

 > Occasionally, drivers care about the value that idr associates with
 > their pointers.
 > 
 > Today we have idr_get_new_above() which allocates a new idr entry
 > above or equal to a given starting id, but sometimes drivers need to
 > force an exact value.
 > 
 > To overcome this small API gap, drivers are wrapping idr_get_new_above
 > and then either BUG_ON() or just call idr_remove() and returns -EBUSY
 > when idr allocates them an id which is different than their requested
 > value.

Looks fine to me as an improvement over the status quo, but I wonder how
many of these places could use the radix_tree stuff instead?  If you're
not using the ability of the idr code to assign an id for you, then it
seems the radix_tree API is a better fit.

 - R.

  parent reply	other threads:[~2010-09-20 20:35 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-20 14:11 idr_get_new_exact ? Ohad Ben-Cohen
2010-09-20 14:11 ` Ohad Ben-Cohen
     [not found] ` <AANLkTi=ZLupVyFR0e2v-TLpeNWdw1bVMZUAhgyxLJ7OV-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-09-20 19:31   ` Andrew Morton
2010-09-20 19:31     ` Andrew Morton
2010-09-20 19:31     ` Andrew Morton
     [not found]     ` <20100920123140.f524de79.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2010-09-20 20:07       ` Steve Wise
2010-09-20 20:07         ` Steve Wise
2010-09-20 20:07         ` Steve Wise
2010-09-20 20:35   ` Roland Dreier [this message]
2010-09-20 20:35     ` Roland Dreier
2010-09-20 20:35     ` Roland Dreier
2010-09-20 20:35     ` Roland Dreier
2010-09-20 21:26     ` Tejun Heo
2010-09-20 21:26       ` Tejun Heo
2010-09-20 21:26       ` Tejun Heo
2010-09-20 21:38       ` [dm-devel] " Alasdair G Kergon
     [not found]       ` <4C97D197.9070703-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2010-09-20 21:38         ` Alasdair G Kergon
2010-09-20 21:38         ` Alasdair G Kergon
2010-09-23 11:42         ` Paul Mundt
2010-09-23 11:42           ` Paul Mundt
2010-09-23 11:42           ` Paul Mundt
2010-09-23 11:46           ` Tejun Heo
2010-09-23 11:46             ` Tejun Heo
2010-09-20 21:38       ` [dm-devel] " Alasdair G Kergon
2010-09-20 21:38         ` Alasdair G Kergon
2010-09-20 21:38         ` Alasdair G Kergon
2010-09-20 21:38         ` Alasdair G Kergon

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