From: Paul Durrant Date: Fri, 20 Apr 2018 13:18:10 +0000 (+0100) Subject: Use a single entry iovec since we're copying data anyway X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=80e8ef41bc44b9df0148c39d88cb731354d5f29b;p=people%2Fpauldu%2Fqemu.git Use a single entry iovec since we're copying data anyway Signed-off-by: Paul Durrant --- diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c index 8f4e229e3a..129f33f224 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -45,15 +45,12 @@ struct ioreq { /* parsed request */ off_t start; - QEMUIOVector v; + void *buf; + size_t size; int presync; - uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST]; - uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST]; - void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST]; - void *pages; - /* aio status */ + QEMUIOVector v; int aio_inflight; int aio_errors; @@ -110,21 +107,17 @@ static void ioreq_reset(struct ioreq *ioreq) memset(&ioreq->req, 0, sizeof(ioreq->req)); ioreq->status = 0; ioreq->start = 0; + ioreq->buf = NULL; + ioreq->size = 0; ioreq->presync = 0; - memset(ioreq->domids, 0, sizeof(ioreq->domids)); - memset(ioreq->refs, 0, sizeof(ioreq->refs)); - memset(ioreq->page, 0, sizeof(ioreq->page)); - ioreq->pages = NULL; - + qemu_iovec_reset(&ioreq->v); ioreq->aio_inflight = 0; ioreq->aio_errors = 0; ioreq->blkdev = NULL; memset(&ioreq->list, 0, sizeof(ioreq->list)); memset(&ioreq->acct, 0, sizeof(ioreq->acct)); - - qemu_iovec_reset(&ioreq->v); } static struct ioreq *ioreq_start(struct XenBlkDev *blkdev) @@ -139,7 +132,7 @@ static struct ioreq *ioreq_start(struct XenBlkDev *blkdev) ioreq = g_malloc0(sizeof(*ioreq)); ioreq->blkdev = blkdev; blkdev->requests_total++; - qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST); + qemu_iovec_init(&ioreq->v, 1); } else { /* get one from freelist */ ioreq = QLIST_FIRST(&blkdev->freelist); @@ -184,7 +177,6 @@ static void ioreq_release(struct ioreq *ioreq, bool finish) static int ioreq_parse(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; - uintptr_t mem; size_t len; int i; @@ -231,14 +223,10 @@ static int ioreq_parse(struct ioreq *ioreq) goto err; } - ioreq->domids[i] = blkdev->xendev.dom; - ioreq->refs[i] = ioreq->req.seg[i].gref; - - mem = ioreq->req.seg[i].first_sect * blkdev->file_blk; len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk; - qemu_iovec_add(&ioreq->v, (void*)mem, len); + ioreq->size += len; } - if (ioreq->start + ioreq->v.size > blkdev->file_size) { + if (ioreq->start + ioreq->size > blkdev->file_size) { xen_pv_printf(&blkdev->xendev, 0, "error: access beyond end of file\n"); goto err; } @@ -251,78 +239,59 @@ err: static void ioreq_free_copy_buffers(struct ioreq *ioreq) { - int i; - - for (i = 0; i < ioreq->v.niov; i++) { - ioreq->page[i] = NULL; - } - - qemu_vfree(ioreq->pages); + qemu_vfree(ioreq->buf); } static int ioreq_init_copy_buffers(struct ioreq *ioreq) { - int i; - - if (ioreq->v.niov == 0) { - return 0; - } - - ioreq->pages = qemu_memalign(XC_PAGE_SIZE, ioreq->v.niov * XC_PAGE_SIZE); - - for (i = 0; i < ioreq->v.niov; i++) { - ioreq->page[i] = ioreq->pages + i * XC_PAGE_SIZE; - ioreq->v.iov[i].iov_base = ioreq->page[i]; - } + ioreq->buf = qemu_memalign(XC_PAGE_SIZE, ioreq->size); return 0; } static int ioreq_grant_copy(struct ioreq *ioreq) { - xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev; + struct XenBlkDev *blkdev = ioreq->blkdev; + xengnttab_handle *gnt = blkdev->xendev.gnttabdev; + void *virt = ioreq->buf; xengnttab_grant_copy_segment_t segs[BLKIF_MAX_SEGMENTS_PER_REQUEST]; - int i, count, rc; - int64_t file_blk = ioreq->blkdev->file_blk; + int i, rc; + int64_t file_blk = blkdev->file_blk; - if (ioreq->v.niov == 0) { - return 0; - } - - count = ioreq->v.niov; - - for (i = 0; i < count; i++) { + for (i = 0; i < ioreq->req.nr_segments; i++) { if (ioreq->req.operation == BLKIF_OP_READ) { segs[i].flags = GNTCOPY_dest_gref; - segs[i].dest.foreign.ref = ioreq->refs[i]; - segs[i].dest.foreign.domid = ioreq->domids[i]; + segs[i].dest.foreign.ref = ioreq->req.seg[i].gref; + segs[i].dest.foreign.domid = blkdev->xendev.dom; segs[i].dest.foreign.offset = ioreq->req.seg[i].first_sect * file_blk; - segs[i].source.virt = ioreq->v.iov[i].iov_base; + segs[i].source.virt = virt; } else { segs[i].flags = GNTCOPY_source_gref; - segs[i].source.foreign.ref = ioreq->refs[i]; - segs[i].source.foreign.domid = ioreq->domids[i]; + segs[i].source.foreign.ref = ioreq->req.seg[i].gref; + segs[i].source.foreign.domid = blkdev->xendev.dom; segs[i].source.foreign.offset = ioreq->req.seg[i].first_sect * file_blk; - segs[i].dest.virt = ioreq->v.iov[i].iov_base; + segs[i].dest.virt = virt; } segs[i].len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * file_blk; + virt += segs[i].len; } - rc = xengnttab_grant_copy(gnt, count, segs); + rc = xengnttab_grant_copy(gnt, ioreq->req.nr_segments, segs); if (rc) { - xen_pv_printf(&ioreq->blkdev->xendev, 0, + xen_pv_printf(&blkdev->xendev, 0, "failed to copy data %d\n", rc); ioreq->aio_errors++; return -1; } - for (i = 0; i < count; i++) { + for (i = 0; i < ioreq->req.nr_segments; i++) { if (segs[i].status != GNTST_okay) { - xen_pv_printf(&ioreq->blkdev->xendev, 3, + xen_pv_printf(&blkdev->xendev, 3, "failed to copy data %d for gref %d, domid %d\n", - segs[i].status, ioreq->refs[i], ioreq->domids[i]); + segs[i].status, ioreq->req.seg[i].gref, + blkdev->xendev.dom); ioreq->aio_errors++; rc = -1; } @@ -455,7 +424,8 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq) switch (ioreq->req.operation) { case BLKIF_OP_READ: block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct, - ioreq->v.size, BLOCK_ACCT_READ); + ioreq->size, BLOCK_ACCT_READ); + qemu_iovec_add(&ioreq->v, ioreq->buf, ioreq->size); ioreq->aio_inflight++; blk_aio_preadv(blkdev->blk, ioreq->start, &ioreq->v, 0, qemu_aio_complete, ioreq); @@ -467,9 +437,10 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq) } block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct, - ioreq->v.size, + ioreq->size, ioreq->req.operation == BLKIF_OP_WRITE ? BLOCK_ACCT_WRITE : BLOCK_ACCT_FLUSH); + qemu_iovec_add(&ioreq->v, ioreq->buf, ioreq->size); ioreq->aio_inflight++; blk_aio_pwritev(blkdev->blk, ioreq->start, &ioreq->v, 0, qemu_aio_complete, ioreq);