diff options
author | Ed L. Cashin <ecashin@coraid.com> | 2006-09-20 22:36:49 +0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2006-10-18 23:53:50 +0400 |
commit | e407a7f6cd143b3ab4eb3d7e1cf882e96b710eb5 (patch) | |
tree | a180d2a6ae40b1fe6773c93a24a5c469948fd59d /drivers/block/aoe/aoedev.c | |
parent | 2fdc0ea75b26e3009cfdf72e79901e4e16bb99bd (diff) | |
download | linux-e407a7f6cd143b3ab4eb3d7e1cf882e96b710eb5.tar.xz |
aoe: zero copy write 1 of 2
Avoid memory copy on writes.
(This patch depends on fixes in patch 9 to follow.)
Although skb->len should not be set when working with linear skbuffs,
the skb->tail pointer maintained by skb_put/skb_trim is not relevant
to what happens when the skb_fill_page_desc function is called. This
issue was raised without comment in linux-kernel and netdev earlier
this month:
http://thread.gmane.org/gmane.linux.kernel/446474/
http://thread.gmane.org/gmane.linux.network/45444/
So until there is something analogous to skb_put that works for
zero-copy write skbuffs, we will do what the other callers of
skb_fill_page_desc are doing.
Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/block/aoe/aoedev.c')
-rw-r--r-- | drivers/block/aoe/aoedev.c | 42 |
1 files changed, 30 insertions, 12 deletions
diff --git a/drivers/block/aoe/aoedev.c b/drivers/block/aoe/aoedev.c index c7e05ed82512..abf1d3c073e3 100644 --- a/drivers/block/aoe/aoedev.c +++ b/drivers/block/aoe/aoedev.c @@ -63,22 +63,32 @@ aoedev_newdev(ulong nframes) struct frame *f, *e; d = kzalloc(sizeof *d, GFP_ATOMIC); - if (d == NULL) - return NULL; f = kcalloc(nframes, sizeof *f, GFP_ATOMIC); - if (f == NULL) { - kfree(d); + switch (!d || !f) { + case 0: + d->nframes = nframes; + d->frames = f; + e = f + nframes; + for (; f<e; f++) { + f->tag = FREETAG; + f->skb = new_skb(ETH_ZLEN); + if (!f->skb) + break; + } + if (f == e) + break; + while (f > d->frames) { + f--; + dev_kfree_skb(f->skb); + } + default: + if (f) + kfree(f); + if (d) + kfree(d); return NULL; } - INIT_WORK(&d->work, aoecmd_sleepwork, d); - - d->nframes = nframes; - d->frames = f; - e = f + nframes; - for (; f<e; f++) - f->tag = FREETAG; - spin_lock_init(&d->lock); init_timer(&d->timer); d->timer.data = (ulong) d; @@ -160,11 +170,19 @@ aoedev_by_sysminor_m(ulong sysminor, ulong bufcnt) static void aoedev_freedev(struct aoedev *d) { + struct frame *f, *e; + if (d->gd) { aoedisk_rm_sysfs(d); del_gendisk(d->gd); put_disk(d->gd); } + f = d->frames; + e = f + d->nframes; + for (; f<e; f++) { + skb_shinfo(f->skb)->nr_frags = 0; + dev_kfree_skb(f->skb); + } kfree(d->frames); if (d->bufpool) mempool_destroy(d->bufpool); |