Re: [Qemu-devel] [PATCH 3/3] ide: add TRIM support

[Kevin Wolf <kwolf@redhat.com>]

Am 19.05.2011 10:58, schrieb Christoph Hellwig:
> Add support for TRIM sub function of the data set management command,
> and wire it up to the qemu discard infrastructure.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> Index: qemu/hw/ide/core.c
> ===================================================================
> --- qemu.orig/hw/ide/core.c	2011-05-18 20:30:20.855172933 +0200
> +++ qemu/hw/ide/core.c	2011-05-18 20:32:26.237625024 +0200
> @@ -124,6 +124,9 @@ static void ide_identify(IDEState *s)
>      put_le16(p + 66, 120);
>      put_le16(p + 67, 120);
>      put_le16(p + 68, 120);
> +    if (dev && dev->conf.discard_granularity) {
> +        put_le16(p + 69, (1 << 14)); /* determinate TRIM behavior */
> +    }
>  
>      if (s->ncq_queues) {
>          put_le16(p + 75, s->ncq_queues - 1);
> @@ -157,6 +160,9 @@ static void ide_identify(IDEState *s)
>      dev = s->unit ? s->bus->slave : s->bus->master;
>      if (dev && dev->conf.physical_block_size)
>          put_le16(p + 106, 0x6000 | get_physical_block_exp(&dev->conf));
> +    if (dev && dev->conf.discard_granularity) {
> +        put_le16(p + 169, 1); /* TRIM support */
> +    }
>  
>      memcpy(s->identify_data, p, sizeof(s->identify_data));
>      s->identify_set = 1;
> @@ -299,6 +305,72 @@ static void ide_set_signature(IDEState *
>      }
>  }
>  
> +typedef struct TrimAIOCB {
> +    BlockDriverAIOCB common;
> +    QEMUBH *bh;
> +    int ret;
> +} TrimAIOCB;
> +
> +static void trim_aio_cancel(BlockDriverAIOCB *acb)
> +{
> +    TrimAIOCB *iocb = container_of(acb, TrimAIOCB, common);
> +
> +    qemu_bh_delete(iocb->bh);
> +    iocb->bh = NULL;
> +    qemu_aio_release(iocb);
> +}
> +
> +static AIOPool trim_aio_pool = {
> +    .aiocb_size         = sizeof(TrimAIOCB),
> +    .cancel             = trim_aio_cancel,
> +};
> +
> +static void ide_trim_bh_cb(void *opaque)
> +{
> +    TrimAIOCB *iocb = opaque;
> +
> +    iocb->common.cb(iocb->common.opaque, iocb->ret);
> +
> +    qemu_bh_delete(iocb->bh);
> +    iocb->bh = NULL;
> +
> +    qemu_aio_release(iocb);
> +}
> +
> +BlockDriverAIOCB *ide_issue_trim(BlockDriverState *bs,
> +        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
> +        BlockDriverCompletionFunc *cb, void *opaque)
> +{
> +    TrimAIOCB *iocb;
> +    int i, j, ret;
> +
> +    iocb = qemu_aio_get(&trim_aio_pool, bs, cb, opaque);
> +    iocb->bh = qemu_bh_new(ide_trim_bh_cb, iocb);
> +    iocb->ret = 0;
> +
> +    for (j = 0; j < qiov->niov; j++) {
> +        uint64_t *buffer = qiov->iov[j].iov_base;
> +
> +        for (i = 0; i < qiov->iov[j].iov_len / 8; i++) {
> +            /* 6-byte LBA + 2-byte range per entry */
> +            uint64_t entry = le64_to_cpu(buffer[i]);
> +            uint64_t sector = entry & 0x0000ffffffffffffULL;
> +            uint16_t count = entry >> 48;
> +
> +            if (count == 0)
> +                break;
> +
> +            ret = bdrv_discard(bs, sector * 512, count * 512);

Hm... bdrv_discard wants sector numbers instead of bytes, doesn't it?

If you agree, I'll send out and apply a fixed and rebased version.

Kevin