Re: [Xen-devel][PATCH v2 2/3] drm/xen-front: Use Xen common shared buffer implementation

[Oleksandr Andrushchenko]

bump

On 12/5/18 10:20 AM, Oleksandr Andrushchenko wrote:
> Hello, Daniel!
>
> Could you please ack/nack the patch, so either we can merge the
>
> series or I can address your comments if any
>
> Thank you,
>
> Oleksandr
>
> On 11/30/18 9:42 AM, Oleksandr Andrushchenko wrote:
> > From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
> >
> > Use page directory based shared buffer implementation
> > now available as common code for Xen frontend drivers.
> >
> > Remove flushing of shared buffer on page flip as this
> > workaround needs a proper fix.
> >
> > Signed-off-by: Oleksandr Andrushchenko 
> > <oleksandr_andrushchenko@xxxxxxxx>
> > ---
> > Â drivers/gpu/drm/xen/KconfigÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂ 1 +
> > Â drivers/gpu/drm/xen/MakefileÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂ 1 -
> > Â drivers/gpu/drm/xen/xen_drm_front.cÂÂÂÂÂÂ |Â 65 ++--
> > Â drivers/gpu/drm/xen/xen_drm_front_gem.cÂÂ |ÂÂ 1 -
> > Â drivers/gpu/drm/xen/xen_drm_front_shbuf.c | 414 ----------------------
> > Â drivers/gpu/drm/xen/xen_drm_front_shbuf.h |Â 64 ----
> > Â 6 files changed, 26 insertions(+), 520 deletions(-)
> > Â delete mode 100644 drivers/gpu/drm/xen/xen_drm_front_shbuf.c
> > Â delete mode 100644 drivers/gpu/drm/xen/xen_drm_front_shbuf.h
> >
> > diff --git a/drivers/gpu/drm/xen/Kconfig b/drivers/gpu/drm/xen/Kconfig
> > index 4cca160782ab..f969d486855d 100644
> > --- a/drivers/gpu/drm/xen/Kconfig
> > +++ b/drivers/gpu/drm/xen/Kconfig
> > @@ -12,6 +12,7 @@ config DRM_XEN_FRONTEND
> > ÂÂÂÂÂ select DRM_KMS_HELPER
> > ÂÂÂÂÂ select VIDEOMODE_HELPERS
> > ÂÂÂÂÂ select XEN_XENBUS_FRONTEND
> > +ÂÂÂ select XEN_FRONT_PGDIR_SHBUF
> > ÂÂÂÂÂ help
> > ÂÂÂÂÂÂÂ Choose this option if you want to enable a para-virtualized
> > ÂÂÂÂÂÂÂ frontend DRM/KMS driver for Xen guest OSes.
> > diff --git a/drivers/gpu/drm/xen/Makefile b/drivers/gpu/drm/xen/Makefile
> > index 712afff5ffc3..825905f67faa 100644
> > --- a/drivers/gpu/drm/xen/Makefile
> > +++ b/drivers/gpu/drm/xen/Makefile
> > @@ -4,7 +4,6 @@ drm_xen_front-objs := xen_drm_front.o \
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_kms.o \
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_conn.o \
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_evtchnl.o \
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_shbuf.o \
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_cfg.o \
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_gem.o
> > Â diff --git a/drivers/gpu/drm/xen/xen_drm_front.c 
> > b/drivers/gpu/drm/xen/xen_drm_front.c
> > index 6b6d5ab82ec3..4d3d36fc3a5d 100644
> > --- a/drivers/gpu/drm/xen/xen_drm_front.c
> > +++ b/drivers/gpu/drm/xen/xen_drm_front.c
> > @@ -19,6 +19,7 @@
> > Â #include <xen/xen.h>
> > Â #include <xen/xenbus.h>
> > Â +#include <xen/xen-front-pgdir-shbuf.h>
> > Â #include <xen/interface/io/displif.h>
> > Â Â #include "xen_drm_front.h"
> > @@ -26,28 +27,20 @@
> > Â #include "xen_drm_front_evtchnl.h"
> > Â #include "xen_drm_front_gem.h"
> > Â #include "xen_drm_front_kms.h"
> > -#include "xen_drm_front_shbuf.h"
> > Â Â struct xen_drm_front_dbuf {
> > ÂÂÂÂÂ struct list_head list;
> > ÂÂÂÂÂ u64 dbuf_cookie;
> > ÂÂÂÂÂ u64 fb_cookie;
> > -ÂÂÂ struct xen_drm_front_shbuf *shbuf;
> > +
> > +ÂÂÂ struct xen_front_pgdir_shbuf shbuf;
> > Â };
> > Â -static int dbuf_add_to_list(struct xen_drm_front_info *front_info,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct xen_drm_front_shbuf *shbuf, u64 dbuf_cookie)
> > +static void dbuf_add_to_list(struct xen_drm_front_info *front_info,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct xen_drm_front_dbuf *dbuf, u64 dbuf_cookie)
> > Â {
> > -ÂÂÂ struct xen_drm_front_dbuf *dbuf;
> > -
> > -ÂÂÂ dbuf = kzalloc(sizeof(*dbuf), GFP_KERNEL);
> > -ÂÂÂ if (!dbuf)
> > -ÂÂÂÂÂÂÂ return -ENOMEM;
> > -
> > ÂÂÂÂÂ dbuf->dbuf_cookie = dbuf_cookie;
> > -ÂÂÂ dbuf->shbuf = shbuf;
> > ÂÂÂÂÂ list_add(&dbuf->list, &front_info->dbuf_list);
> > -ÂÂÂ return 0;
> > Â }
> > Â Â static struct xen_drm_front_dbuf *dbuf_get(struct list_head 
> > *dbuf_list,
> > @@ -62,15 +55,6 @@ static struct xen_drm_front_dbuf *dbuf_get(struct 
> > list_head *dbuf_list,
> > ÂÂÂÂÂ return NULL;
> > Â }
> > Â -static void dbuf_flush_fb(struct list_head *dbuf_list, u64 fb_cookie)
> > -{
> > -ÂÂÂ struct xen_drm_front_dbuf *buf, *q;
> > -
> > -ÂÂÂ list_for_each_entry_safe(buf, q, dbuf_list, list)
> > -ÂÂÂÂÂÂÂ if (buf->fb_cookie == fb_cookie)
> > -ÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_shbuf_flush(buf->shbuf);
> > -}
> > -
> > Â static void dbuf_free(struct list_head *dbuf_list, u64 dbuf_cookie)
> > Â {
> > ÂÂÂÂÂ struct xen_drm_front_dbuf *buf, *q;
> > @@ -78,8 +62,8 @@ static void dbuf_free(struct list_head *dbuf_list, 
> > u64 dbuf_cookie)
> > ÂÂÂÂÂ list_for_each_entry_safe(buf, q, dbuf_list, list)
> > ÂÂÂÂÂÂÂÂÂ if (buf->dbuf_cookie == dbuf_cookie) {
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂ list_del(&buf->list);
> > -ÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_shbuf_unmap(buf->shbuf);
> > -ÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_shbuf_free(buf->shbuf);
> > +ÂÂÂÂÂÂÂÂÂÂÂ xen_front_pgdir_shbuf_unmap(&buf->shbuf);
> > +ÂÂÂÂÂÂÂÂÂÂÂ xen_front_pgdir_shbuf_free(&buf->shbuf);
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂ kfree(buf);
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂ break;
> > ÂÂÂÂÂÂÂÂÂ }
> > @@ -91,8 +75,8 @@ static void dbuf_free_all(struct list_head *dbuf_list)
> > Â ÂÂÂÂÂ list_for_each_entry_safe(buf, q, dbuf_list, list) {
> > ÂÂÂÂÂÂÂÂÂ list_del(&buf->list);
> > -ÂÂÂÂÂÂÂ xen_drm_front_shbuf_unmap(buf->shbuf);
> > -ÂÂÂÂÂÂÂ xen_drm_front_shbuf_free(buf->shbuf);
> > +ÂÂÂÂÂÂÂ xen_front_pgdir_shbuf_unmap(&buf->shbuf);
> > +ÂÂÂÂÂÂÂ xen_front_pgdir_shbuf_free(&buf->shbuf);
> > ÂÂÂÂÂÂÂÂÂ kfree(buf);
> > ÂÂÂÂÂ }
> > Â }
> > @@ -171,9 +155,9 @@ int xen_drm_front_dbuf_create(struct 
> > xen_drm_front_info *front_info,
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ u32 bpp, u64 size, struct page **pages)
> > Â {
> > ÂÂÂÂÂ struct xen_drm_front_evtchnl *evtchnl;
> > -ÂÂÂ struct xen_drm_front_shbuf *shbuf;
> > +ÂÂÂ struct xen_drm_front_dbuf *dbuf;
> > ÂÂÂÂÂ struct xendispl_req *req;
> > -ÂÂÂ struct xen_drm_front_shbuf_cfg buf_cfg;
> > +ÂÂÂ struct xen_front_pgdir_shbuf_cfg buf_cfg;
> > ÂÂÂÂÂ unsigned long flags;
> > ÂÂÂÂÂ int ret;
> > Â @@ -181,28 +165,29 @@ int xen_drm_front_dbuf_create(struct 
> > xen_drm_front_info *front_info,
> > ÂÂÂÂÂ if (unlikely(!evtchnl))
> > ÂÂÂÂÂÂÂÂÂ return -EIO;
> > Â +ÂÂÂ dbuf = kzalloc(sizeof(*dbuf), GFP_KERNEL);
> > +ÂÂÂ if (!dbuf)
> > +ÂÂÂÂÂÂÂ return -ENOMEM;
> > +
> > +ÂÂÂ dbuf_add_to_list(front_info, dbuf, dbuf_cookie);
> > +
> > ÂÂÂÂÂ memset(&buf_cfg, 0, sizeof(buf_cfg));
> > ÂÂÂÂÂ buf_cfg.xb_dev = front_info->xb_dev;
> > +ÂÂÂ buf_cfg.num_pages = DIV_ROUND_UP(size, PAGE_SIZE);
> > ÂÂÂÂÂ buf_cfg.pages = pages;
> > -ÂÂÂ buf_cfg.size = size;
> > +ÂÂÂ buf_cfg.pgdir = &dbuf->shbuf;
> > ÂÂÂÂÂ buf_cfg.be_alloc = front_info->cfg.be_alloc;
> > Â -ÂÂÂ shbuf = xen_drm_front_shbuf_alloc(&buf_cfg);
> > -ÂÂÂ if (IS_ERR(shbuf))
> > -ÂÂÂÂÂÂÂ return PTR_ERR(shbuf);
> > -
> > -ÂÂÂ ret = dbuf_add_to_list(front_info, shbuf, dbuf_cookie);
> > -ÂÂÂ if (ret < 0) {
> > -ÂÂÂÂÂÂÂ xen_drm_front_shbuf_free(shbuf);
> > -ÂÂÂÂÂÂÂ return ret;
> > -ÂÂÂ }
> > +ÂÂÂ ret = xen_front_pgdir_shbuf_alloc(&buf_cfg);
> > +ÂÂÂ if (ret < 0)
> > +ÂÂÂÂÂÂÂ goto fail_shbuf_alloc;
> > Â ÂÂÂÂÂ mutex_lock(&evtchnl->u.req.req_io_lock);
> > Â ÂÂÂÂÂ spin_lock_irqsave(&front_info->io_lock, flags);
> > ÂÂÂÂÂ req = be_prepare_req(evtchnl, XENDISPL_OP_DBUF_CREATE);
> > ÂÂÂÂÂ req->op.dbuf_create.gref_directory =
> > -ÂÂÂÂÂÂÂÂÂÂÂ xen_drm_front_shbuf_get_dir_start(shbuf);
> > + xen_front_pgdir_shbuf_get_dir_start(&dbuf->shbuf);
> > ÂÂÂÂÂ req->op.dbuf_create.buffer_sz = size;
> > ÂÂÂÂÂ req->op.dbuf_create.dbuf_cookie = dbuf_cookie;
> > ÂÂÂÂÂ req->op.dbuf_create.width = width;
> > @@ -221,7 +206,7 @@ int xen_drm_front_dbuf_create(struct 
> > xen_drm_front_info *front_info,
> > ÂÂÂÂÂ if (ret < 0)
> > ÂÂÂÂÂÂÂÂÂ goto fail;
> > Â -ÂÂÂ ret = xen_drm_front_shbuf_map(shbuf);
> > +ÂÂÂ ret = xen_front_pgdir_shbuf_map(&dbuf->shbuf);
> > ÂÂÂÂÂ if (ret < 0)
> > ÂÂÂÂÂÂÂÂÂ goto fail;
> > Â @@ -230,6 +215,7 @@ int xen_drm_front_dbuf_create(struct 
> > xen_drm_front_info *front_info,
> > Â Â fail:
> > ÂÂÂÂÂ mutex_unlock(&evtchnl->u.req.req_io_lock);
> > +fail_shbuf_alloc:
> > ÂÂÂÂÂ dbuf_free(&front_info->dbuf_list, dbuf_cookie);
> > ÂÂÂÂÂ return ret;
> > Â }
> > @@ -358,7 +344,6 @@ int xen_drm_front_page_flip(struct 
> > xen_drm_front_info *front_info,
> > ÂÂÂÂÂ if (unlikely(conn_idx >= front_info->num_evt_pairs))
> > ÂÂÂÂÂÂÂÂÂ return -EINVAL;
> > Â -ÂÂÂ dbuf_flush_fb(&front_info->dbuf_list, fb_cookie);
> > ÂÂÂÂÂ evtchnl = &front_info->evt_pairs[conn_idx].req;
> > Â ÂÂÂÂÂ mutex_lock(&evtchnl->u.req.req_io_lock);
> > diff --git a/drivers/gpu/drm/xen/xen_drm_front_gem.c 
> > b/drivers/gpu/drm/xen/xen_drm_front_gem.c
> > index c85bfe7571cb..53be4c7dc0a4 100644
> > --- a/drivers/gpu/drm/xen/xen_drm_front_gem.c
> > +++ b/drivers/gpu/drm/xen/xen_drm_front_gem.c
> > @@ -22,7 +22,6 @@
> > Â #include <xen/balloon.h>
> > Â Â #include "xen_drm_front.h"
> > -#include "xen_drm_front_shbuf.h"
> > Â Â struct xen_gem_object {
> > ÂÂÂÂÂ struct drm_gem_object base;
> > diff --git a/drivers/gpu/drm/xen/xen_drm_front_shbuf.c 
> > b/drivers/gpu/drm/xen/xen_drm_front_shbuf.c
> > deleted file mode 100644
> > index d333b67cc1a0..000000000000
> > --- a/drivers/gpu/drm/xen/xen_drm_front_shbuf.c
> > +++ /dev/null
> > @@ -1,414 +0,0 @@
> > -// SPDX-License-Identifier: GPL-2.0 OR MIT
> > -
> > -/*
> > - *Â Xen para-virtual DRM device
> > - *
> > - * Copyright (C) 2016-2018 EPAM Systems Inc.
> > - *
> > - * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
> > - */
> > -
> > -#include <drm/drmP.h>
> > -
> > -#if defined(CONFIG_X86)
> > -#include <drm/drm_cache.h>
> > -#endif
> > -#include <linux/errno.h>
> > -#include <linux/mm.h>
> > -
> > -#include <asm/xen/hypervisor.h>
> > -#include <xen/balloon.h>
> > -#include <xen/xen.h>
> > -#include <xen/xenbus.h>
> > -#include <xen/interface/io/ring.h>
> > -#include <xen/interface/io/displif.h>
> > -
> > -#include "xen_drm_front.h"
> > -#include "xen_drm_front_shbuf.h"
> > -
> > -struct xen_drm_front_shbuf_ops {
> > -ÂÂÂ /*
> > -ÂÂÂÂ * Calculate number of grefs required to handle this buffer,
> > -ÂÂÂÂ * e.g. if grefs are required for page directory only or the buffer
> > -ÂÂÂÂ * pages as well.
> > -ÂÂÂÂ */
> > -ÂÂÂ void (*calc_num_grefs)(struct xen_drm_front_shbuf *buf);
> > -ÂÂÂ /* Fill page directory according to para-virtual display 
> > protocol. */
> > -ÂÂÂ void (*fill_page_dir)(struct xen_drm_front_shbuf *buf);
> > -ÂÂÂ /* Claim grant references for the pages of the buffer. */
> > -ÂÂÂ int (*grant_refs_for_buffer)(struct xen_drm_front_shbuf *buf,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ grant_ref_t *priv_gref_head, int gref_idx);
> > -ÂÂÂ /* Map grant references of the buffer. */
> > -ÂÂÂ int (*map)(struct xen_drm_front_shbuf *buf);
> > -ÂÂÂ /* Unmap grant references of the buffer. */
> > -ÂÂÂ int (*unmap)(struct xen_drm_front_shbuf *buf);
> > -};
> > -
> > -grant_ref_t xen_drm_front_shbuf_get_dir_start(struct 
> > xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ if (!buf->grefs)
> > -ÂÂÂÂÂÂÂ return GRANT_INVALID_REF;
> > -
> > -ÂÂÂ return buf->grefs[0];
> > -}
> > -
> > -int xen_drm_front_shbuf_map(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ if (buf->ops->map)
> > -ÂÂÂÂÂÂÂ return buf->ops->map(buf);
> > -
> > -ÂÂÂ /* no need to map own grant references */
> > -ÂÂÂ return 0;
> > -}
> > -
> > -int xen_drm_front_shbuf_unmap(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ if (buf->ops->unmap)
> > -ÂÂÂÂÂÂÂ return buf->ops->unmap(buf);
> > -
> > -ÂÂÂ /* no need to unmap own grant references */
> > -ÂÂÂ return 0;
> > -}
> > -
> > -void xen_drm_front_shbuf_flush(struct xen_drm_front_shbuf *buf)
> > -{
> > -#if defined(CONFIG_X86)
> > -ÂÂÂ drm_clflush_pages(buf->pages, buf->num_pages);
> > -#endif
> > -}
> > -
> > -void xen_drm_front_shbuf_free(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ if (buf->grefs) {
> > -ÂÂÂÂÂÂÂ int i;
> > -
> > -ÂÂÂÂÂÂÂ for (i = 0; i < buf->num_grefs; i++)
> > -ÂÂÂÂÂÂÂÂÂÂÂ if (buf->grefs[i] != GRANT_INVALID_REF)
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ gnttab_end_foreign_access(buf->grefs[i],
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 0, 0UL);
> > -ÂÂÂ }
> > -ÂÂÂ kfree(buf->grefs);
> > -ÂÂÂ kfree(buf->directory);
> > -ÂÂÂ kfree(buf);
> > -}
> > -
> > -/*
> > - * number of grefs a page can hold with respect to the
> > - * struct xendispl_page_directory header
> > - */
> > -#define XEN_DRM_NUM_GREFS_PER_PAGE ((PAGE_SIZE - \
> > -ÂÂÂÂÂÂÂ offsetof(struct xendispl_page_directory, gref)) / \
> > -ÂÂÂÂÂÂÂ sizeof(grant_ref_t))
> > -
> > -static int get_num_pages_dir(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ /* number of pages the page directory consumes itself */
> > -ÂÂÂ return DIV_ROUND_UP(buf->num_pages, XEN_DRM_NUM_GREFS_PER_PAGE);
> > -}
> > -
> > -static void backend_calc_num_grefs(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ /* only for pages the page directory consumes itself */
> > -ÂÂÂ buf->num_grefs = get_num_pages_dir(buf);
> > -}
> > -
> > -static void guest_calc_num_grefs(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ /*
> > -ÂÂÂÂ * number of pages the page directory consumes itself
> > -ÂÂÂÂ * plus grefs for the buffer pages
> > -ÂÂÂÂ */
> > -ÂÂÂ buf->num_grefs = get_num_pages_dir(buf) + buf->num_pages;
> > -}
> > -
> > -#define xen_page_to_vaddr(page) \
> > -ÂÂÂÂÂÂÂ ((uintptr_t)pfn_to_kaddr(page_to_xen_pfn(page)))
> > -
> > -static int backend_unmap(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ struct gnttab_unmap_grant_ref *unmap_ops;
> > -ÂÂÂ int i, ret;
> > -
> > -ÂÂÂ if (!buf->pages || !buf->backend_map_handles || !buf->grefs)
> > -ÂÂÂÂÂÂÂ return 0;
> > -
> > -ÂÂÂ unmap_ops = kcalloc(buf->num_pages, sizeof(*unmap_ops),
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ GFP_KERNEL);
> > -ÂÂÂ if (!unmap_ops) {
> > -ÂÂÂÂÂÂÂ DRM_ERROR("Failed to get memory while unmapping\n");
> > -ÂÂÂÂÂÂÂ return -ENOMEM;
> > -ÂÂÂ }
> > -
> > -ÂÂÂ for (i = 0; i < buf->num_pages; i++) {
> > -ÂÂÂÂÂÂÂ phys_addr_t addr;
> > -
> > -ÂÂÂÂÂÂÂ addr = xen_page_to_vaddr(buf->pages[i]);
> > -ÂÂÂÂÂÂÂ gnttab_set_unmap_op(&unmap_ops[i], addr, GNTMAP_host_map,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ buf->backend_map_handles[i]);
> > -ÂÂÂ }
> > -
> > -ÂÂÂ ret = gnttab_unmap_refs(unmap_ops, NULL, buf->pages,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ buf->num_pages);
> > -
> > -ÂÂÂ for (i = 0; i < buf->num_pages; i++) {
> > -ÂÂÂÂÂÂÂ if (unlikely(unmap_ops[i].status != GNTST_okay))
> > -ÂÂÂÂÂÂÂÂÂÂÂ DRM_ERROR("Failed to unmap page %d: %d\n",
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ i, unmap_ops[i].status);
> > -ÂÂÂ }
> > -
> > -ÂÂÂ if (ret)
> > -ÂÂÂÂÂÂÂ DRM_ERROR("Failed to unmap grant references, ret %d", ret);
> > -
> > -ÂÂÂ kfree(unmap_ops);
> > -ÂÂÂ kfree(buf->backend_map_handles);
> > -ÂÂÂ buf->backend_map_handles = NULL;
> > -ÂÂÂ return ret;
> > -}
> > -
> > -static int backend_map(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ struct gnttab_map_grant_ref *map_ops = NULL;
> > -ÂÂÂ unsigned char *ptr;
> > -ÂÂÂ int ret, cur_gref, cur_dir_page, cur_page, grefs_left;
> > -
> > -ÂÂÂ map_ops = kcalloc(buf->num_pages, sizeof(*map_ops), GFP_KERNEL);
> > -ÂÂÂ if (!map_ops)
> > -ÂÂÂÂÂÂÂ return -ENOMEM;
> > -
> > -ÂÂÂ buf->backend_map_handles = kcalloc(buf->num_pages,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ sizeof(*buf->backend_map_handles),
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ GFP_KERNEL);
> > -ÂÂÂ if (!buf->backend_map_handles) {
> > -ÂÂÂÂÂÂÂ kfree(map_ops);
> > -ÂÂÂÂÂÂÂ return -ENOMEM;
> > -ÂÂÂ }
> > -
> > -ÂÂÂ /*
> > -ÂÂÂÂ * read page directory to get grefs from the backend: for external
> > -ÂÂÂÂ * buffer we only allocate buf->grefs for the page directory,
> > -ÂÂÂÂ * so buf->num_grefs has number of pages in the page directory 
> > itself
> > -ÂÂÂÂ */
> > -ÂÂÂ ptr = buf->directory;
> > -ÂÂÂ grefs_left = buf->num_pages;
> > -ÂÂÂ cur_page = 0;
> > -ÂÂÂ for (cur_dir_page = 0; cur_dir_page < buf->num_grefs; 
> > cur_dir_page++) {
> > -ÂÂÂÂÂÂÂ struct xendispl_page_directory *page_dir =
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ (struct xendispl_page_directory *)ptr;
> > -ÂÂÂÂÂÂÂ int to_copy = XEN_DRM_NUM_GREFS_PER_PAGE;
> > -
> > -ÂÂÂÂÂÂÂ if (to_copy > grefs_left)
> > -ÂÂÂÂÂÂÂÂÂÂÂ to_copy = grefs_left;
> > -
> > -ÂÂÂÂÂÂÂ for (cur_gref = 0; cur_gref < to_copy; cur_gref++) {
> > -ÂÂÂÂÂÂÂÂÂÂÂ phys_addr_t addr;
> > -
> > -ÂÂÂÂÂÂÂÂÂÂÂ addr = xen_page_to_vaddr(buf->pages[cur_page]);
> > -ÂÂÂÂÂÂÂÂÂÂÂ gnttab_set_map_op(&map_ops[cur_page], addr,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ GNTMAP_host_map,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ page_dir->gref[cur_gref],
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ buf->xb_dev->otherend_id);
> > -ÂÂÂÂÂÂÂÂÂÂÂ cur_page++;
> > -ÂÂÂÂÂÂÂ }
> > -
> > -ÂÂÂÂÂÂÂ grefs_left -= to_copy;
> > -ÂÂÂÂÂÂÂ ptr += PAGE_SIZE;
> > -ÂÂÂ }
> > -ÂÂÂ ret = gnttab_map_refs(map_ops, NULL, buf->pages, buf->num_pages);
> > -
> > -ÂÂÂ /* save handles even if error, so we can unmap */
> > -ÂÂÂ for (cur_page = 0; cur_page < buf->num_pages; cur_page++) {
> > -ÂÂÂÂÂÂÂ buf->backend_map_handles[cur_page] = map_ops[cur_page].handle;
> > -ÂÂÂÂÂÂÂ if (unlikely(map_ops[cur_page].status != GNTST_okay))
> > -ÂÂÂÂÂÂÂÂÂÂÂ DRM_ERROR("Failed to map page %d: %d\n",
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ cur_page, map_ops[cur_page].status);
> > -ÂÂÂ }
> > -
> > -ÂÂÂ if (ret) {
> > -ÂÂÂÂÂÂÂ DRM_ERROR("Failed to map grant references, ret %d", ret);
> > -ÂÂÂÂÂÂÂ backend_unmap(buf);
> > -ÂÂÂ }
> > -
> > -ÂÂÂ kfree(map_ops);
> > -ÂÂÂ return ret;
> > -}
> > -
> > -static void backend_fill_page_dir(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ struct xendispl_page_directory *page_dir;
> > -ÂÂÂ unsigned char *ptr;
> > -ÂÂÂ int i, num_pages_dir;
> > -
> > -ÂÂÂ ptr = buf->directory;
> > -ÂÂÂ num_pages_dir = get_num_pages_dir(buf);
> > -
> > -ÂÂÂ /* fill only grefs for the page directory itself */
> > -ÂÂÂ for (i = 0; i < num_pages_dir - 1; i++) {
> > -ÂÂÂÂÂÂÂ page_dir = (struct xendispl_page_directory *)ptr;
> > -
> > -ÂÂÂÂÂÂÂ page_dir->gref_dir_next_page = buf->grefs[i + 1];
> > -ÂÂÂÂÂÂÂ ptr += PAGE_SIZE;
> > -ÂÂÂ }
> > -ÂÂÂ /* last page must say there is no more pages */
> > -ÂÂÂ page_dir = (struct xendispl_page_directory *)ptr;
> > -ÂÂÂ page_dir->gref_dir_next_page = GRANT_INVALID_REF;
> > -}
> > -
> > -static void guest_fill_page_dir(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ unsigned char *ptr;
> > -ÂÂÂ int cur_gref, grefs_left, to_copy, i, num_pages_dir;
> > -
> > -ÂÂÂ ptr = buf->directory;
> > -ÂÂÂ num_pages_dir = get_num_pages_dir(buf);
> > -
> > -ÂÂÂ /*
> > -ÂÂÂÂ * while copying, skip grefs at start, they are for pages
> > -ÂÂÂÂ * granted for the page directory itself
> > -ÂÂÂÂ */
> > -ÂÂÂ cur_gref = num_pages_dir;
> > -ÂÂÂ grefs_left = buf->num_pages;
> > -ÂÂÂ for (i = 0; i < num_pages_dir; i++) {
> > -ÂÂÂÂÂÂÂ struct xendispl_page_directory *page_dir =
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ (struct xendispl_page_directory *)ptr;
> > -
> > -ÂÂÂÂÂÂÂ if (grefs_left <= XEN_DRM_NUM_GREFS_PER_PAGE) {
> > -ÂÂÂÂÂÂÂÂÂÂÂ to_copy = grefs_left;
> > -ÂÂÂÂÂÂÂÂÂÂÂ page_dir->gref_dir_next_page = GRANT_INVALID_REF;
> > -ÂÂÂÂÂÂÂ } else {
> > -ÂÂÂÂÂÂÂÂÂÂÂ to_copy = XEN_DRM_NUM_GREFS_PER_PAGE;
> > -ÂÂÂÂÂÂÂÂÂÂÂ page_dir->gref_dir_next_page = buf->grefs[i + 1];
> > -ÂÂÂÂÂÂÂ }
> > -ÂÂÂÂÂÂÂ memcpy(&page_dir->gref, &buf->grefs[cur_gref],
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ to_copy * sizeof(grant_ref_t));
> > -ÂÂÂÂÂÂÂ ptr += PAGE_SIZE;
> > -ÂÂÂÂÂÂÂ grefs_left -= to_copy;
> > -ÂÂÂÂÂÂÂ cur_gref += to_copy;
> > -ÂÂÂ }
> > -}
> > -
> > -static int guest_grant_refs_for_buffer(struct xen_drm_front_shbuf *buf,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ grant_ref_t *priv_gref_head,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ int gref_idx)
> > -{
> > -ÂÂÂ int i, cur_ref, otherend_id;
> > -
> > -ÂÂÂ otherend_id = buf->xb_dev->otherend_id;
> > -ÂÂÂ for (i = 0; i < buf->num_pages; i++) {
> > -ÂÂÂÂÂÂÂ cur_ref = gnttab_claim_grant_reference(priv_gref_head);
> > -ÂÂÂÂÂÂÂ if (cur_ref < 0)
> > -ÂÂÂÂÂÂÂÂÂÂÂ return cur_ref;
> > -
> > -ÂÂÂÂÂÂÂ gnttab_grant_foreign_access_ref(cur_ref, otherend_id,
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ xen_page_to_gfn(buf->pages[i]),
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 0);
> > -ÂÂÂÂÂÂÂ buf->grefs[gref_idx++] = cur_ref;
> > -ÂÂÂ }
> > -ÂÂÂ return 0;
> > -}
> > -
> > -static int grant_references(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ grant_ref_t priv_gref_head;
> > -ÂÂÂ int ret, i, j, cur_ref;
> > -ÂÂÂ int otherend_id, num_pages_dir;
> > -
> > -ÂÂÂ ret = gnttab_alloc_grant_references(buf->num_grefs, 
> > &priv_gref_head);
> > -ÂÂÂ if (ret < 0) {
> > -ÂÂÂÂÂÂÂ DRM_ERROR("Cannot allocate grant references\n");
> > -ÂÂÂÂÂÂÂ return ret;
> > -ÂÂÂ }
> > -
> > -ÂÂÂ otherend_id = buf->xb_dev->otherend_id;
> > -ÂÂÂ j = 0;
> > -ÂÂÂ num_pages_dir = get_num_pages_dir(buf);
> > -ÂÂÂ for (i = 0; i < num_pages_dir; i++) {
> > -ÂÂÂÂÂÂÂ unsigned long frame;
> > -
> > -ÂÂÂÂÂÂÂ cur_ref = gnttab_claim_grant_reference(&priv_gref_head);
> > -ÂÂÂÂÂÂÂ if (cur_ref < 0)
> > -ÂÂÂÂÂÂÂÂÂÂÂ return cur_ref;
> > -
> > -ÂÂÂÂÂÂÂ frame = xen_page_to_gfn(virt_to_page(buf->directory +
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ PAGE_SIZE * i));
> > -ÂÂÂÂÂÂÂ gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 
> > 0);
> > -ÂÂÂÂÂÂÂ buf->grefs[j++] = cur_ref;
> > -ÂÂÂ }
> > -
> > -ÂÂÂ if (buf->ops->grant_refs_for_buffer) {
> > -ÂÂÂÂÂÂÂ ret = buf->ops->grant_refs_for_buffer(buf, &priv_gref_head, j);
> > -ÂÂÂÂÂÂÂ if (ret)
> > -ÂÂÂÂÂÂÂÂÂÂÂ return ret;
> > -ÂÂÂ }
> > -
> > -ÂÂÂ gnttab_free_grant_references(priv_gref_head);
> > -ÂÂÂ return 0;
> > -}
> > -
> > -static int alloc_storage(struct xen_drm_front_shbuf *buf)
> > -{
> > -ÂÂÂ buf->grefs = kcalloc(buf->num_grefs, sizeof(*buf->grefs), 
> > GFP_KERNEL);
> > -ÂÂÂ if (!buf->grefs)
> > -ÂÂÂÂÂÂÂ return -ENOMEM;
> > -
> > -ÂÂÂ buf->directory = kcalloc(get_num_pages_dir(buf), PAGE_SIZE, 
> > GFP_KERNEL);
> > -ÂÂÂ if (!buf->directory)
> > -ÂÂÂÂÂÂÂ return -ENOMEM;
> > -
> > -ÂÂÂ return 0;
> > -}
> > -
> > -/*
> > - * For be allocated buffers we don't need grant_refs_for_buffer as 
> > those
> > - * grant references are allocated at backend side
> > - */
> > -static const struct xen_drm_front_shbuf_ops backend_ops = {
> > -ÂÂÂ .calc_num_grefs = backend_calc_num_grefs,
> > -ÂÂÂ .fill_page_dir = backend_fill_page_dir,
> > -ÂÂÂ .map = backend_map,
> > -ÂÂÂ .unmap = backend_unmap
> > -};
> > -
> > -/* For locally granted references we do not need to map/unmap the 
> > references */
> > -static const struct xen_drm_front_shbuf_ops local_ops = {
> > -ÂÂÂ .calc_num_grefs = guest_calc_num_grefs,
> > -ÂÂÂ .fill_page_dir = guest_fill_page_dir,
> > -ÂÂÂ .grant_refs_for_buffer = guest_grant_refs_for_buffer,
> > -};
> > -
> > -struct xen_drm_front_shbuf *
> > -xen_drm_front_shbuf_alloc(struct xen_drm_front_shbuf_cfg *cfg)
> > -{
> > -ÂÂÂ struct xen_drm_front_shbuf *buf;
> > -ÂÂÂ int ret;
> > -
> > -ÂÂÂ buf = kzalloc(sizeof(*buf), GFP_KERNEL);
> > -ÂÂÂ if (!buf)
> > -ÂÂÂÂÂÂÂ return ERR_PTR(-ENOMEM);
> > -
> > -ÂÂÂ if (cfg->be_alloc)
> > -ÂÂÂÂÂÂÂ buf->ops = &backend_ops;
> > -ÂÂÂ else
> > -ÂÂÂÂÂÂÂ buf->ops = &local_ops;
> > -
> > -ÂÂÂ buf->xb_dev = cfg->xb_dev;
> > -ÂÂÂ buf->num_pages = DIV_ROUND_UP(cfg->size, PAGE_SIZE);
> > -ÂÂÂ buf->pages = cfg->pages;
> > -
> > -ÂÂÂ buf->ops->calc_num_grefs(buf);
> > -
> > -ÂÂÂ ret = alloc_storage(buf);
> > -ÂÂÂ if (ret)
> > -ÂÂÂÂÂÂÂ goto fail;
> > -
> > -ÂÂÂ ret = grant_references(buf);
> > -ÂÂÂ if (ret)
> > -ÂÂÂÂÂÂÂ goto fail;
> > -
> > -ÂÂÂ buf->ops->fill_page_dir(buf);
> > -
> > -ÂÂÂ return buf;
> > -
> > -fail:
> > -ÂÂÂ xen_drm_front_shbuf_free(buf);
> > -ÂÂÂ return ERR_PTR(ret);
> > -}
> > diff --git a/drivers/gpu/drm/xen/xen_drm_front_shbuf.h 
> > b/drivers/gpu/drm/xen/xen_drm_front_shbuf.h
> > deleted file mode 100644
> > index 7545c692539e..000000000000
> > --- a/drivers/gpu/drm/xen/xen_drm_front_shbuf.h
> > +++ /dev/null
> > @@ -1,64 +0,0 @@
> > -/* SPDX-License-Identifier: GPL-2.0 OR MIT */
> > -
> > -/*
> > - *Â Xen para-virtual DRM device
> > - *
> > - * Copyright (C) 2016-2018 EPAM Systems Inc.
> > - *
> > - * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
> > - */
> > -
> > -#ifndef __XEN_DRM_FRONT_SHBUF_H_
> > -#define __XEN_DRM_FRONT_SHBUF_H_
> > -
> > -#include <linux/kernel.h>
> > -#include <linux/scatterlist.h>
> > -
> > -#include <xen/grant_table.h>
> > -
> > -struct xen_drm_front_shbuf {
> > -ÂÂÂ /*
> > -ÂÂÂÂ * number of references granted for the backend use:
> > -ÂÂÂÂ *Â - for allocated/imported dma-buf's this holds number of grant
> > -ÂÂÂÂ *ÂÂÂ references for the page directory and pages of the buffer
> > -ÂÂÂÂ *Â - for the buffer provided by the backend this holds number of
> > -ÂÂÂÂ *ÂÂÂ grant references for the page directory as grant 
> > references for
> > -ÂÂÂÂ *ÂÂÂ the buffer will be provided by the backend
> > -ÂÂÂÂ */
> > -ÂÂÂ int num_grefs;
> > -ÂÂÂ grant_ref_t *grefs;
> > -ÂÂÂ unsigned char *directory;
> > -
> > -ÂÂÂ int num_pages;
> > -ÂÂÂ struct page **pages;
> > -
> > -ÂÂÂ struct xenbus_device *xb_dev;
> > -
> > -ÂÂÂ /* these are the ops used internally depending on be_alloc mode */
> > -ÂÂÂ const struct xen_drm_front_shbuf_ops *ops;
> > -
> > -ÂÂÂ /* Xen map handles for the buffer allocated by the backend */
> > -ÂÂÂ grant_handle_t *backend_map_handles;
> > -};
> > -
> > -struct xen_drm_front_shbuf_cfg {
> > -ÂÂÂ struct xenbus_device *xb_dev;
> > -ÂÂÂ size_t size;
> > -ÂÂÂ struct page **pages;
> > -ÂÂÂ bool be_alloc;
> > -};
> > -
> > -struct xen_drm_front_shbuf *
> > -xen_drm_front_shbuf_alloc(struct xen_drm_front_shbuf_cfg *cfg);
> > -
> > -grant_ref_t xen_drm_front_shbuf_get_dir_start(struct 
> > xen_drm_front_shbuf *buf);
> > -
> > -int xen_drm_front_shbuf_map(struct xen_drm_front_shbuf *buf);
> > -
> > -int xen_drm_front_shbuf_unmap(struct xen_drm_front_shbuf *buf);
> > -
> > -void xen_drm_front_shbuf_flush(struct xen_drm_front_shbuf *buf);
> > -
> > -void xen_drm_front_shbuf_free(struct xen_drm_front_shbuf *buf);
> > -
> > -#endif /* __XEN_DRM_FRONT_SHBUF_H_ */