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aoe: retain static block device numbers for backwards compatibility

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The old mapping between AoE target shelf and slot addresses and the block
device minor number is retained as a backwards-compatible feature, with a
new "aoe_dyndevs" module parameter available for enabling dynamic block
device minor numbers.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ed Cashin 2012-10-04 17:16:42 -07:00 committed by Linus Torvalds
parent 0c96621458
commit 4bcce1a355
1 changed files with 51 additions and 3 deletions
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54
drivers/block/aoe/aoedev.c
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@ -11,6 +11,7 @@
#include <linux/slab.h>
#include <linux/bitmap.h>
#include <linux/kdev_t.h>
#include <linux/moduleparam.h>
#include "aoe.h"
static void dummy_timer(ulong);
@ -18,6 +19,10 @@ static void aoedev_freedev(struct aoedev *);
static void freetgt(struct aoedev *d, struct aoetgt *t);
static void skbpoolfree(struct aoedev *d);
static int aoe_dyndevs;
module_param(aoe_dyndevs, int, 0644);
MODULE_PARM_DESC(aoe_dyndevs, "Use dynamic minor numbers for devices.");
static struct aoedev *devlist;
static DEFINE_SPINLOCK(devlist_lock);
@ -34,7 +39,7 @@ static DEFINE_SPINLOCK(used_minors_lock);
static DECLARE_BITMAP(used_minors, N_DEVS);
static int
minor_get(ulong *minor)
minor_get_dyn(ulong *sysminor)
{
ulong flags;
ulong n;
@ -48,10 +53,53 @@ minor_get(ulong *minor)
error = -1;
spin_unlock_irqrestore(&used_minors_lock, flags);
*minor = n * AOE_PARTITIONS;
*sysminor = n * AOE_PARTITIONS;
return error;
}
static int
minor_get_static(ulong *sysminor, ulong aoemaj, int aoemin)
{
ulong flags;
ulong n;
int error = 0;
enum {
/* for backwards compatibility when !aoe_dyndevs,
* a static number of supported slots per shelf */
NPERSHELF = 16,
};
n = aoemaj * NPERSHELF + aoemin;
if (aoemin >= NPERSHELF || n >= N_DEVS) {
pr_err("aoe: %s with e%ld.%d\n",
"cannot use static minor device numbers",
aoemaj, aoemin);
error = -1;
} else {
spin_lock_irqsave(&used_minors_lock, flags);
if (test_bit(n, used_minors)) {
pr_err("aoe: %s %lu\n",
"existing device already has static minor number",
n);
error = -1;
} else
set_bit(n, used_minors);
spin_unlock_irqrestore(&used_minors_lock, flags);
}
*sysminor = n;
return error;
}
static int
minor_get(ulong *sysminor, ulong aoemaj, int aoemin)
{
if (aoe_dyndevs)
return minor_get_dyn(sysminor);
else
return minor_get_static(sysminor, aoemaj, aoemin);
}
static void
minor_free(ulong minor)
{
@ -293,7 +341,7 @@ aoedev_by_aoeaddr(ulong maj, int min, int do_alloc)
d->ref++;
break;
}
if (d || !do_alloc || minor_get(&sysminor) < 0)
if (d || !do_alloc || minor_get(&sysminor, maj, min) < 0)
goto out;
d = kcalloc(1, sizeof *d, GFP_ATOMIC);
if (!d)