[2/4] block/xen_disk: remove use of grant map/unmap

Message ID	1525089699-13411-3-git-send-email-paul.durrant@citrix.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org> From: Paul Durrant <paul.durrant@citrix.com> To: <xen-devel@lists.xenproject.org>, <qemu-block@nongnu.org>, <qemu-devel@nongnu.org> Date: Mon, 30 Apr 2018 13:01:37 +0100 Message-ID: <1525089699-13411-3-git-send-email-paul.durrant@citrix.com> In-Reply-To: <1525089699-13411-1-git-send-email-paul.durrant@citrix.com> References: <1525089699-13411-1-git-send-email-paul.durrant@citrix.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH 2/4] block/xen_disk: remove use of grant map/unmap Precedence: list Cc: Anthony Perard <anthony.perard@citrix.com>, Kevin Wolf <kwolf@redhat.com>, Paul Durrant <paul.durrant@citrix.com>, Stefano Stabellini <sstabellini@kernel.org>, Max Reitz <mreitz@redhat.com> Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" <qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org>

diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c index b33611a..8f4e229 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -36,10 +36,6 @@ /* ------------------------------------------------------------- */ -static int batch_maps = 0; - -/* ------------------------------------------------------------- */ - #define BLOCK_SIZE 512 #define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2) @@ -51,12 +47,9 @@ struct ioreq { off_t start; QEMUIOVector v; int presync; - uint8_t mapped; - /* grant mapping */ uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST]; uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST]; - int prot; void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST]; void *pages; @@ -89,7 +82,6 @@ struct XenBlkDev { int protocol; blkif_back_rings_t rings; int more_work; - int cnt_map; /* request lists */ QLIST_HEAD(inflight_head, ioreq) inflight; @@ -119,11 +111,9 @@ static void ioreq_reset(struct ioreq *ioreq) ioreq->status = 0; ioreq->start = 0; ioreq->presync = 0; - ioreq->mapped = 0; memset(ioreq->domids, 0, sizeof(ioreq->domids)); memset(ioreq->refs, 0, sizeof(ioreq->refs)); - ioreq->prot = 0; memset(ioreq->page, 0, sizeof(ioreq->page)); ioreq->pages = NULL; @@ -204,7 +194,6 @@ static int ioreq_parse(struct ioreq *ioreq) ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number); switch (ioreq->req.operation) { case BLKIF_OP_READ: - ioreq->prot = PROT_WRITE; /* to memory */ break; case BLKIF_OP_FLUSH_DISKCACHE: ioreq->presync = 1; @@ -213,7 +202,6 @@ static int ioreq_parse(struct ioreq *ioreq) } /* fall through */ case BLKIF_OP_WRITE: - ioreq->prot = PROT_READ; /* from memory */ break; case BLKIF_OP_DISCARD: return 0; @@ -261,88 +249,6 @@ err: return -1; } -static void ioreq_unmap(struct ioreq *ioreq) -{ - xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev; - int i; - - if (ioreq->v.niov == 0 || ioreq->mapped == 0) { - return; - } - if (batch_maps) { - if (!ioreq->pages) { - return; - } - if (xengnttab_unmap(gnt, ioreq->pages, ioreq->v.niov) != 0) { - xen_pv_printf(&ioreq->blkdev->xendev, 0, - "xengnttab_unmap failed: %s\n", - strerror(errno)); - } - ioreq->blkdev->cnt_map -= ioreq->v.niov; - ioreq->pages = NULL; - } else { - for (i = 0; i < ioreq->v.niov; i++) { - if (!ioreq->page[i]) { - continue; - } - if (xengnttab_unmap(gnt, ioreq->page[i], 1) != 0) { - xen_pv_printf(&ioreq->blkdev->xendev, 0, - "xengnttab_unmap failed: %s\n", - strerror(errno)); - } - ioreq->blkdev->cnt_map--; - ioreq->page[i] = NULL; - } - } - ioreq->mapped = 0; -} - -static int ioreq_map(struct ioreq *ioreq) -{ - xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev; - int i; - - if (ioreq->v.niov == 0 || ioreq->mapped == 1) { - return 0; - } - if (batch_maps) { - ioreq->pages = xengnttab_map_grant_refs - (gnt, ioreq->v.niov, ioreq->domids, ioreq->refs, ioreq->prot); - if (ioreq->pages == NULL) { - xen_pv_printf(&ioreq->blkdev->xendev, 0, - "can't map %d grant refs (%s, %d maps)\n", - ioreq->v.niov, strerror(errno), - ioreq->blkdev->cnt_map); - return -1; - } - for (i = 0; i < ioreq->v.niov; i++) { - ioreq->v.iov[i].iov_base = ioreq->pages + i * XC_PAGE_SIZE + - (uintptr_t)ioreq->v.iov[i].iov_base; - } - ioreq->blkdev->cnt_map += ioreq->v.niov; - } else { - for (i = 0; i < ioreq->v.niov; i++) { - ioreq->page[i] = xengnttab_map_grant_ref - (gnt, ioreq->domids[i], ioreq->refs[i], ioreq->prot); - if (ioreq->page[i] == NULL) { - xen_pv_printf(&ioreq->blkdev->xendev, 0, - "can't map grant ref %d (%s, %d maps)\n", - ioreq->refs[i], strerror(errno), - ioreq->blkdev->cnt_map); - ioreq->mapped = 1; - ioreq_unmap(ioreq); - return -1; - } - ioreq->v.iov[i].iov_base = ioreq->page[i] + - (uintptr_t)ioreq->v.iov[i].iov_base; - } - } - ioreq->mapped = 1; - return 0; -} - -#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40800 - static void ioreq_free_copy_buffers(struct ioreq *ioreq) { int i; @@ -424,22 +330,6 @@ static int ioreq_grant_copy(struct ioreq *ioreq) return rc; } -#else -static void ioreq_free_copy_buffers(struct ioreq *ioreq) -{ - abort(); -} - -static int ioreq_init_copy_buffers(struct ioreq *ioreq) -{ - abort(); -} - -static int ioreq_grant_copy(struct ioreq *ioreq) -{ - abort(); -} -#endif static int ioreq_runio_qemu_aio(struct ioreq *ioreq); @@ -466,32 +356,28 @@ static void qemu_aio_complete(void *opaque, int ret) goto done; } - if (xen_feature_grant_copy) { - switch (ioreq->req.operation) { - case BLKIF_OP_READ: - /* in case of failure ioreq->aio_errors is increased */ - if (ret == 0) { - ioreq_grant_copy(ioreq); - } - ioreq_free_copy_buffers(ioreq); - break; - case BLKIF_OP_WRITE: - case BLKIF_OP_FLUSH_DISKCACHE: - if (!ioreq->req.nr_segments) { - break; - } - ioreq_free_copy_buffers(ioreq); - break; - default: + switch (ioreq->req.operation) { + case BLKIF_OP_READ: + /* in case of failure ioreq->aio_errors is increased */ + if (ret == 0) { + ioreq_grant_copy(ioreq); + } + ioreq_free_copy_buffers(ioreq); + break; + case BLKIF_OP_WRITE: + case BLKIF_OP_FLUSH_DISKCACHE: + if (!ioreq->req.nr_segments) { break; } + ioreq_free_copy_buffers(ioreq); + break; + default: + break; } ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY; - if (!xen_feature_grant_copy) { - ioreq_unmap(ioreq); - } ioreq_finish(ioreq); + switch (ioreq->req.operation) { case BLKIF_OP_WRITE: case BLKIF_OP_FLUSH_DISKCACHE: @@ -551,18 +437,13 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; - if (xen_feature_grant_copy) { - ioreq_init_copy_buffers(ioreq); - if (ioreq->req.nr_segments && (ioreq->req.operation == BLKIF_OP_WRITE || - ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) && - ioreq_grant_copy(ioreq)) { - ioreq_free_copy_buffers(ioreq); - goto err; - } - } else { - if (ioreq->req.nr_segments && ioreq_map(ioreq)) { - goto err; - } + ioreq_init_copy_buffers(ioreq); + if (ioreq->req.nr_segments && + (ioreq->req.operation == BLKIF_OP_WRITE || + ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) && + ioreq_grant_copy(ioreq)) { + ioreq_free_copy_buffers(ioreq); + goto err; } ioreq->aio_inflight++; @@ -603,9 +484,6 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq) } default: /* unknown operation (shouldn't happen -- parse catches this) */ - if (!xen_feature_grant_copy) { - ioreq_unmap(ioreq); - } goto err; } @@ -791,10 +669,6 @@ static void blk_alloc(struct XenDevice *xendev) blkdev->ctx = iothread_get_aio_context(blkdev->iothread); blkdev->bh = aio_bh_new(blkdev->ctx, blk_bh, blkdev); - - if (xen_mode != XEN_EMULATE) { - batch_maps = 1; - } } static void blk_parse_discard(struct XenBlkDev *blkdev) @@ -877,8 +751,9 @@ static int blk_init(struct XenDevice *xendev) blkdev->file_blk = BLOCK_SIZE; - xen_pv_printf(&blkdev->xendev, 3, "grant copy operation %s\n", - xen_feature_grant_copy ? "enabled" : "disabled"); + if (!xen_feature_grant_copy) { + goto out_error; + } /* fill info * blk_connect supplies sector-size and sectors @@ -910,15 +785,6 @@ out_error: return -1; } -/* - * We need to account for the grant allocations requiring contiguous - * chunks; the worst case number would be - * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, - * but in order to keep things simple just use - * 2 * max_req * max_seg. - */ -#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) - static int blk_connect(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); @@ -1079,11 +945,8 @@ static int blk_connect(struct XenDevice *xendev) return -1; } - /* Calculate the maximum number of grants needed by ioreqs */ - max_grants = MAX_GRANTS(blkdev->max_requests, - BLKIF_MAX_SEGMENTS_PER_REQUEST); /* Add on the number needed for the ring pages */ - max_grants += blkdev->nr_ring_ref; + max_grants = blkdev->nr_ring_ref; blkdev->xendev.gnttabdev = xengnttab_open(NULL, 0); if (blkdev->xendev.gnttabdev == NULL) { @@ -1114,8 +977,6 @@ static int blk_connect(struct XenDevice *xendev) return -1; } - blkdev->cnt_map++; - switch (blkdev->protocol) { case BLKIF_PROTOCOL_NATIVE: { @@ -1171,7 +1032,6 @@ static void blk_disconnect(struct XenDevice *xendev) if (blkdev->sring) { xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, blkdev->nr_ring_ref); - blkdev->cnt_map--; blkdev->sring = NULL; }

[2/4] block/xen_disk: remove use of grant map/unmap

Commit Message

Comments

Patch