diff options
author | Ed Cashin <ecashin@coraid.com> | 2012-10-04 17:16:40 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-06 03:05:28 +0900 |
commit | 0c966214589b9767fd8771b71328f83bac58cb25 (patch) | |
tree | fa46832f149cb30b1847bc6eee13e79ef9c0c444 /drivers/block/aoe/aoedev.c | |
parent | eecdf226721673095ef7849f960350897392e8bf (diff) |
aoe: support more AoE addresses with dynamic block device minor numbers
The ATA over Ethernet protocol uses a major (shelf) and minor (slot)
address to identify a particular storage target. These changes remove an
artificial limitation the aoe driver imposes on the use of AoE addresses.
For example, without these changes, the slot address has a maximum of 15,
but users commonly use slot numbers much greater than that.
The AoE shelf and slot address space is often used sparsely. Instead of
using a static mapping between AoE addresses and the block device minor
number, the block device minor numbers are now allocated on demand.
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>
Diffstat (limited to 'drivers/block/aoe/aoedev.c')
-rw-r--r-- | drivers/block/aoe/aoedev.c | 86 |
1 files changed, 59 insertions, 27 deletions
diff --git a/drivers/block/aoe/aoedev.c b/drivers/block/aoe/aoedev.c index ccaecff4c69b..68a7a5a9ced0 100644 --- a/drivers/block/aoe/aoedev.c +++ b/drivers/block/aoe/aoedev.c @@ -9,6 +9,8 @@ #include <linux/netdevice.h> #include <linux/delay.h> #include <linux/slab.h> +#include <linux/bitmap.h> +#include <linux/kdev_t.h> #include "aoe.h" static void dummy_timer(ulong); @@ -19,35 +21,63 @@ static void skbpoolfree(struct aoedev *d); static struct aoedev *devlist; static DEFINE_SPINLOCK(devlist_lock); -/* - * Users who grab a pointer to the device with aoedev_by_aoeaddr or - * aoedev_by_sysminor_m automatically get a reference count and must - * be responsible for performing a aoedev_put. With the addition of - * async kthread processing I'm no longer confident that we can - * guarantee consistency in the face of device flushes. - * - * For the time being, we only bother to add extra references for - * frames sitting on the iocq. When the kthreads finish processing - * these frames, they will aoedev_put the device. +/* Because some systems will have one, many, or no + * - partitions, + * - slots per shelf, + * - or shelves, + * we need some flexibility in the way the minor numbers + * are allocated. So they are dynamic. */ -struct aoedev * -aoedev_by_aoeaddr(int maj, int min) +#define N_DEVS ((1U<<MINORBITS)/AOE_PARTITIONS) + +static DEFINE_SPINLOCK(used_minors_lock); +static DECLARE_BITMAP(used_minors, N_DEVS); + +static int +minor_get(ulong *minor) { - struct aoedev *d; ulong flags; + ulong n; + int error = 0; + + spin_lock_irqsave(&used_minors_lock, flags); + n = find_first_zero_bit(used_minors, N_DEVS); + if (n < N_DEVS) + set_bit(n, used_minors); + else + error = -1; + spin_unlock_irqrestore(&used_minors_lock, flags); + + *minor = n * AOE_PARTITIONS; + return error; +} - spin_lock_irqsave(&devlist_lock, flags); +static void +minor_free(ulong minor) +{ + ulong flags; - for (d=devlist; d; d=d->next) - if (d->aoemajor == maj && d->aoeminor == min) { - d->ref++; - break; - } + minor /= AOE_PARTITIONS; + BUG_ON(minor >= N_DEVS); - spin_unlock_irqrestore(&devlist_lock, flags); - return d; + spin_lock_irqsave(&used_minors_lock, flags); + BUG_ON(!test_bit(minor, used_minors)); + clear_bit(minor, used_minors); + spin_unlock_irqrestore(&used_minors_lock, flags); } +/* + * Users who grab a pointer to the device with aoedev_by_aoeaddr + * automatically get a reference count and must be responsible + * for performing a aoedev_put. With the addition of async + * kthread processing I'm no longer confident that we can + * guarantee consistency in the face of device flushes. + * + * For the time being, we only bother to add extra references for + * frames sitting on the iocq. When the kthreads finish processing + * these frames, they will aoedev_put the device. + */ + void aoedev_put(struct aoedev *d) { @@ -159,6 +189,7 @@ aoedev_freedev(struct aoedev *d) if (d->bufpool) mempool_destroy(d->bufpool); skbpoolfree(d); + minor_free(d->sysminor); kfree(d); } @@ -246,22 +277,23 @@ skbpoolfree(struct aoedev *d) __skb_queue_head_init(&d->skbpool); } -/* find it or malloc it */ +/* find it or allocate it */ struct aoedev * -aoedev_by_sysminor_m(ulong sysminor) +aoedev_by_aoeaddr(ulong maj, int min, int do_alloc) { struct aoedev *d; int i; ulong flags; + ulong sysminor; spin_lock_irqsave(&devlist_lock, flags); for (d=devlist; d; d=d->next) - if (d->sysminor == sysminor) { + if (d->aoemajor == maj && d->aoeminor == min) { d->ref++; break; } - if (d) + if (d || !do_alloc || minor_get(&sysminor) < 0) goto out; d = kcalloc(1, sizeof *d, GFP_ATOMIC); if (!d) @@ -280,8 +312,8 @@ aoedev_by_sysminor_m(ulong sysminor) for (i = 0; i < NFACTIVE; i++) INIT_LIST_HEAD(&d->factive[i]); d->sysminor = sysminor; - d->aoemajor = AOEMAJOR(sysminor); - d->aoeminor = AOEMINOR(sysminor); + d->aoemajor = maj; + d->aoeminor = min; d->mintimer = MINTIMER; d->next = devlist; devlist = d; |