| Message ID | 20210716141426.1904528-7-jason@jlekstrand.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: Migrate memory to SMEM when imported cross-device (v7) | expand |
On Fri, 16 Jul 2021 at 15:14, Jason Ekstrand <jason@jlekstrand.net> wrote: > > From: Thomas Hellström <thomas.hellstrom@linux.intel.com> > > If our exported dma-bufs are imported by another instance of our driver, > that instance will typically have the imported dma-bufs locked during > dma_buf_map_attachment(). But the exporter also locks the same reservation > object in the map_dma_buf() callback, which leads to recursive locking. > > So taking the lock inside _pin_pages_unlocked() is incorrect. > > Additionally, the current pinning code path is contrary to the defined > way that pinning should occur. > > Remove the explicit pin/unpin from the map/umap functions and move them > to the attach/detach allowing correct locking to occur, and to match > the static dma-buf drm_prime pattern. > > Add a live selftest to exercise both dynamic and non-dynamic > exports. > > v2: > - Extend the selftest with a fake dynamic importer. > - Provide real pin and unpin callbacks to not abuse the interface. > v3: (ruhl) > - Remove the dynamic export support and move the pinning into the > attach/detach path. > v4: (ruhl) > - Put pages does not need to assert on the dma-resv > v5: (jason) > - Lock around dma_buf_unmap_attachment() when emulating a dynamic > importer in the subtests. > - Use pin_pages_unlocked > v6: (jason) > - Use dma_buf_attach instead of dma_buf_attach_dynamic in the selftests > > Reported-by: Michael J. Ruhl <michael.j.ruhl@intel.com> > Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> > Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com> > Signed-off-by: Jason Ekstrand <jason@jlekstrand.net> > Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> > --- > drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 43 ++++++-- > .../drm/i915/gem/selftests/i915_gem_dmabuf.c | 103 +++++++++++++++++- > 2 files changed, 132 insertions(+), 14 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > index 616c3a2f1baf0..9a655f69a0671 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > @@ -12,6 +12,8 @@ > #include "i915_gem_object.h" > #include "i915_scatterlist.h" > > +I915_SELFTEST_DECLARE(static bool force_different_devices;) > + > static struct drm_i915_gem_object *dma_buf_to_obj(struct dma_buf *buf) > { > return to_intel_bo(buf->priv); > @@ -25,15 +27,11 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme > struct scatterlist *src, *dst; > int ret, i; > > - ret = i915_gem_object_pin_pages_unlocked(obj); > - if (ret) > - goto err; > - > /* Copy sg so that we make an independent mapping */ > st = kmalloc(sizeof(struct sg_table), GFP_KERNEL); > if (st == NULL) { > ret = -ENOMEM; > - goto err_unpin_pages; > + goto err; > } > > ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL); > @@ -58,8 +56,6 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme > sg_free_table(st); > err_free: > kfree(st); > -err_unpin_pages: > - i915_gem_object_unpin_pages(obj); > err: > return ERR_PTR(ret); > } > @@ -68,13 +64,9 @@ static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment, > struct sg_table *sg, > enum dma_data_direction dir) > { > - struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf); > - > dma_unmap_sgtable(attachment->dev, sg, dir, DMA_ATTR_SKIP_CPU_SYNC); > sg_free_table(sg); > kfree(sg); > - > - i915_gem_object_unpin_pages(obj); > } > > static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map) > @@ -168,7 +160,31 @@ static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direct > return err; > } > > +/** > + * i915_gem_dmabuf_attach - Do any extra attach work necessary > + * @dmabuf: imported dma-buf > + * @attach: new attach to do work on > + * > + */ > +static int i915_gem_dmabuf_attach(struct dma_buf *dmabuf, > + struct dma_buf_attachment *attach) > +{ > + struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf); > + > + return i915_gem_object_pin_pages_unlocked(obj); > +} > + > +static void i915_gem_dmabuf_detach(struct dma_buf *dmabuf, > + struct dma_buf_attachment *attach) > +{ > + struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf); > + > + i915_gem_object_unpin_pages(obj); > +} > + We don't normally add kernel-doc for static functions? Otherwise dmabuf_detach() needs matching kernel-doc. <snip> > + > +static int igt_dmabuf_import_same_driver(void *arg) > +{ > + struct drm_i915_private *i915 = arg; > + struct drm_i915_gem_object *obj, *import_obj; > + struct drm_gem_object *import; > + struct dma_buf *dmabuf; > + struct dma_buf_attachment *import_attach; > + struct sg_table *st; > + long timeout; > + int err; > + > + force_different_devices = true; > + obj = i915_gem_object_create_shmem(i915, PAGE_SIZE); > + if (IS_ERR(obj)) err = PTR_ERR(obj) <snip> > + /* Now try a fake an importer */ > + import_attach = dma_buf_attach(dmabuf, obj->base.dev->dev); > + if (IS_ERR(import_attach)) > + goto out_import; > + > + st = dma_buf_map_attachment(import_attach, DMA_BIDIRECTIONAL); > + if (IS_ERR(st)) > + goto out_detach; For these two maybe missing err = ?
On Tue, Jul 20, 2021 at 4:07 AM Matthew Auld <matthew.william.auld@gmail.com> wrote: > > On Fri, 16 Jul 2021 at 15:14, Jason Ekstrand <jason@jlekstrand.net> wrote: > > > > From: Thomas Hellström <thomas.hellstrom@linux.intel.com> > > > > If our exported dma-bufs are imported by another instance of our driver, > > that instance will typically have the imported dma-bufs locked during > > dma_buf_map_attachment(). But the exporter also locks the same reservation > > object in the map_dma_buf() callback, which leads to recursive locking. > > > > So taking the lock inside _pin_pages_unlocked() is incorrect. > > > > Additionally, the current pinning code path is contrary to the defined > > way that pinning should occur. > > > > Remove the explicit pin/unpin from the map/umap functions and move them > > to the attach/detach allowing correct locking to occur, and to match > > the static dma-buf drm_prime pattern. > > > > Add a live selftest to exercise both dynamic and non-dynamic > > exports. > > > > v2: > > - Extend the selftest with a fake dynamic importer. > > - Provide real pin and unpin callbacks to not abuse the interface. > > v3: (ruhl) > > - Remove the dynamic export support and move the pinning into the > > attach/detach path. > > v4: (ruhl) > > - Put pages does not need to assert on the dma-resv > > v5: (jason) > > - Lock around dma_buf_unmap_attachment() when emulating a dynamic > > importer in the subtests. > > - Use pin_pages_unlocked > > v6: (jason) > > - Use dma_buf_attach instead of dma_buf_attach_dynamic in the selftests > > > > Reported-by: Michael J. Ruhl <michael.j.ruhl@intel.com> > > Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> > > Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com> > > Signed-off-by: Jason Ekstrand <jason@jlekstrand.net> > > Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> > > --- > > drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 43 ++++++-- > > .../drm/i915/gem/selftests/i915_gem_dmabuf.c | 103 +++++++++++++++++- > > 2 files changed, 132 insertions(+), 14 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > > index 616c3a2f1baf0..9a655f69a0671 100644 > > --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > > +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > > @@ -12,6 +12,8 @@ > > #include "i915_gem_object.h" > > #include "i915_scatterlist.h" > > > > +I915_SELFTEST_DECLARE(static bool force_different_devices;) > > + > > static struct drm_i915_gem_object *dma_buf_to_obj(struct dma_buf *buf) > > { > > return to_intel_bo(buf->priv); > > @@ -25,15 +27,11 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme > > struct scatterlist *src, *dst; > > int ret, i; > > > > - ret = i915_gem_object_pin_pages_unlocked(obj); > > - if (ret) > > - goto err; > > - > > /* Copy sg so that we make an independent mapping */ > > st = kmalloc(sizeof(struct sg_table), GFP_KERNEL); > > if (st == NULL) { > > ret = -ENOMEM; > > - goto err_unpin_pages; > > + goto err; > > } > > > > ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL); > > @@ -58,8 +56,6 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme > > sg_free_table(st); > > err_free: > > kfree(st); > > -err_unpin_pages: > > - i915_gem_object_unpin_pages(obj); > > err: > > return ERR_PTR(ret); > > } > > @@ -68,13 +64,9 @@ static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment, > > struct sg_table *sg, > > enum dma_data_direction dir) > > { > > - struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf); > > - > > dma_unmap_sgtable(attachment->dev, sg, dir, DMA_ATTR_SKIP_CPU_SYNC); > > sg_free_table(sg); > > kfree(sg); > > - > > - i915_gem_object_unpin_pages(obj); > > } > > > > static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map) > > @@ -168,7 +160,31 @@ static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direct > > return err; > > } > > > > +/** > > + * i915_gem_dmabuf_attach - Do any extra attach work necessary > > + * @dmabuf: imported dma-buf > > + * @attach: new attach to do work on > > + * > > + */ > > +static int i915_gem_dmabuf_attach(struct dma_buf *dmabuf, > > + struct dma_buf_attachment *attach) > > +{ > > + struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf); > > + > > + return i915_gem_object_pin_pages_unlocked(obj); > > +} > > + > > +static void i915_gem_dmabuf_detach(struct dma_buf *dmabuf, > > + struct dma_buf_attachment *attach) > > +{ > > + struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf); > > + > > + i915_gem_object_unpin_pages(obj); > > +} > > + > > We don't normally add kernel-doc for static functions? Otherwise > dmabuf_detach() needs matching kernel-doc. Dropped. > <snip> > > > + > > +static int igt_dmabuf_import_same_driver(void *arg) > > +{ > > + struct drm_i915_private *i915 = arg; > > + struct drm_i915_gem_object *obj, *import_obj; > > + struct drm_gem_object *import; > > + struct dma_buf *dmabuf; > > + struct dma_buf_attachment *import_attach; > > + struct sg_table *st; > > + long timeout; > > + int err; > > + > > + force_different_devices = true; > > + obj = i915_gem_object_create_shmem(i915, PAGE_SIZE); > > + if (IS_ERR(obj)) > > err = PTR_ERR(obj) Done. > <snip> > > > + /* Now try a fake an importer */ > > + import_attach = dma_buf_attach(dmabuf, obj->base.dev->dev); > > + if (IS_ERR(import_attach)) > > + goto out_import; > > + > > + st = dma_buf_map_attachment(import_attach, DMA_BIDIRECTIONAL); > > + if (IS_ERR(st)) > > + goto out_detach; > > For these two maybe missing err = ? Yup. Fixed. I also changed the (int)PTR_ERR() in the error prints like you asked for in the next patch. --Jason
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c index 616c3a2f1baf0..9a655f69a0671 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c @@ -12,6 +12,8 @@ #include "i915_gem_object.h" #include "i915_scatterlist.h" +I915_SELFTEST_DECLARE(static bool force_different_devices;) + static struct drm_i915_gem_object *dma_buf_to_obj(struct dma_buf *buf) { return to_intel_bo(buf->priv); @@ -25,15 +27,11 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme struct scatterlist *src, *dst; int ret, i; - ret = i915_gem_object_pin_pages_unlocked(obj); - if (ret) - goto err; - /* Copy sg so that we make an independent mapping */ st = kmalloc(sizeof(struct sg_table), GFP_KERNEL); if (st == NULL) { ret = -ENOMEM; - goto err_unpin_pages; + goto err; } ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL); @@ -58,8 +56,6 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme sg_free_table(st); err_free: kfree(st); -err_unpin_pages: - i915_gem_object_unpin_pages(obj); err: return ERR_PTR(ret); } @@ -68,13 +64,9 @@ static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_table *sg, enum dma_data_direction dir) { - struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf); - dma_unmap_sgtable(attachment->dev, sg, dir, DMA_ATTR_SKIP_CPU_SYNC); sg_free_table(sg); kfree(sg); - - i915_gem_object_unpin_pages(obj); } static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map) @@ -168,7 +160,31 @@ static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direct return err; } +/** + * i915_gem_dmabuf_attach - Do any extra attach work necessary + * @dmabuf: imported dma-buf + * @attach: new attach to do work on + * + */ +static int i915_gem_dmabuf_attach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attach) +{ + struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf); + + return i915_gem_object_pin_pages_unlocked(obj); +} + +static void i915_gem_dmabuf_detach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attach) +{ + struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf); + + i915_gem_object_unpin_pages(obj); +} + static const struct dma_buf_ops i915_dmabuf_ops = { + .attach = i915_gem_dmabuf_attach, + .detach = i915_gem_dmabuf_detach, .map_dma_buf = i915_gem_map_dma_buf, .unmap_dma_buf = i915_gem_unmap_dma_buf, .release = drm_gem_dmabuf_release, @@ -204,6 +220,8 @@ static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj) struct sg_table *pages; unsigned int sg_page_sizes; + assert_object_held(obj); + pages = dma_buf_map_attachment(obj->base.import_attach, DMA_BIDIRECTIONAL); if (IS_ERR(pages)) @@ -241,7 +259,8 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev, if (dma_buf->ops == &i915_dmabuf_ops) { obj = dma_buf_to_obj(dma_buf); /* is it from our device? */ - if (obj->base.dev == dev) { + if (obj->base.dev == dev && + !I915_SELFTEST_ONLY(force_different_devices)) { /* * Importing dmabuf exported from out own gem increases * refcount on gem itself instead of f_count of dmabuf. diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c index dd74bc09ec88d..4451bbb4917e4 100644 --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c @@ -35,7 +35,7 @@ static int igt_dmabuf_export(void *arg) static int igt_dmabuf_import_self(void *arg) { struct drm_i915_private *i915 = arg; - struct drm_i915_gem_object *obj; + struct drm_i915_gem_object *obj, *import_obj; struct drm_gem_object *import; struct dma_buf *dmabuf; int err; @@ -65,14 +65,112 @@ static int igt_dmabuf_import_self(void *arg) err = -EINVAL; goto out_import; } + import_obj = to_intel_bo(import); + + i915_gem_object_lock(import_obj, NULL); + err = ____i915_gem_object_get_pages(import_obj); + i915_gem_object_unlock(import_obj); + if (err) { + pr_err("Same object dma-buf get_pages failed!\n"); + goto out_import; + } err = 0; out_import: - i915_gem_object_put(to_intel_bo(import)); + i915_gem_object_put(import_obj); +out_dmabuf: + dma_buf_put(dmabuf); +out: + i915_gem_object_put(obj); + return err; +} + +static int igt_dmabuf_import_same_driver(void *arg) +{ + struct drm_i915_private *i915 = arg; + struct drm_i915_gem_object *obj, *import_obj; + struct drm_gem_object *import; + struct dma_buf *dmabuf; + struct dma_buf_attachment *import_attach; + struct sg_table *st; + long timeout; + int err; + + force_different_devices = true; + obj = i915_gem_object_create_shmem(i915, PAGE_SIZE); + if (IS_ERR(obj)) + goto out_ret; + + dmabuf = i915_gem_prime_export(&obj->base, 0); + if (IS_ERR(dmabuf)) { + pr_err("i915_gem_prime_export failed with err=%d\n", + (int)PTR_ERR(dmabuf)); + err = PTR_ERR(dmabuf); + goto out; + } + + import = i915_gem_prime_import(&i915->drm, dmabuf); + if (IS_ERR(import)) { + pr_err("i915_gem_prime_import failed with err=%d\n", + (int)PTR_ERR(import)); + err = PTR_ERR(import); + goto out_dmabuf; + } + + if (import == &obj->base) { + pr_err("i915_gem_prime_import reused gem object!\n"); + err = -EINVAL; + goto out_import; + } + + import_obj = to_intel_bo(import); + + i915_gem_object_lock(import_obj, NULL); + err = ____i915_gem_object_get_pages(import_obj); + if (err) { + pr_err("Different objects dma-buf get_pages failed!\n"); + i915_gem_object_unlock(import_obj); + goto out_import; + } + + /* + * If the exported object is not in system memory, something + * weird is going on. TODO: When p2p is supported, this is no + * longer considered weird. + */ + if (obj->mm.region != i915->mm.regions[INTEL_REGION_SMEM]) { + pr_err("Exported dma-buf is not in system memory\n"); + err = -EINVAL; + } + + i915_gem_object_unlock(import_obj); + + /* Now try a fake an importer */ + import_attach = dma_buf_attach(dmabuf, obj->base.dev->dev); + if (IS_ERR(import_attach)) + goto out_import; + + st = dma_buf_map_attachment(import_attach, DMA_BIDIRECTIONAL); + if (IS_ERR(st)) + goto out_detach; + + timeout = dma_resv_wait_timeout(dmabuf->resv, false, true, 5 * HZ); + if (!timeout) { + pr_err("dmabuf wait for exclusive fence timed out.\n"); + timeout = -ETIME; + } + err = timeout > 0 ? 0 : timeout; + dma_buf_unmap_attachment(import_attach, st, DMA_BIDIRECTIONAL); +out_detach: + dma_buf_detach(dmabuf, import_attach); +out_import: + i915_gem_object_put(import_obj); out_dmabuf: dma_buf_put(dmabuf); out: i915_gem_object_put(obj); +out_ret: + force_different_devices = false; return err; } @@ -286,6 +384,7 @@ int i915_gem_dmabuf_live_selftests(struct drm_i915_private *i915) { static const struct i915_subtest tests[] = { SUBTEST(igt_dmabuf_export), + SUBTEST(igt_dmabuf_import_same_driver), }; return i915_subtests(tests, i915);