From patchwork Tue Jan 27 08:25:54 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sumit Semwal X-Patchwork-Id: 28056 Received: from mail.tu-berlin.de ([130.149.7.33]) by www.linuxtv.org with esmtp (Exim 4.72) (envelope-from ) id 1YG1Ty-0003si-Ji; Tue, 27 Jan 2015 09:26:46 +0100 X-tubIT-Incoming-IP: 209.132.180.67 Received: from vger.kernel.org ([209.132.180.67]) by mail.tu-berlin.de (exim-4.72/mailfrontend-5) with esmtp id 1YG1Tv-0000Ph-9Z; Tue, 27 Jan 2015 09:26:46 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757368AbbA0I02 (ORCPT + 1 other); Tue, 27 Jan 2015 03:26:28 -0500 Received: from mail-pd0-f173.google.com ([209.85.192.173]:51168 "EHLO mail-pd0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757278AbbA0I0Z (ORCPT ); Tue, 27 Jan 2015 03:26:25 -0500 Received: by mail-pd0-f173.google.com with SMTP id fp1so17543605pdb.4 for ; Tue, 27 Jan 2015 00:26:25 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=+CIYcTmczoXjZcEWfOWJuLz6AIGpqPwCzSPsGP4z2+s=; b=WyQTpx1N3Gw9tV/QQGq/IdUijQeyDlTZm0cwcHA0JnzJfWHNFL/rajh//nb41CIsYH OQk5+7b05hDbROm1zuN7auzR4URLLz1e5CZ7ULcUjw36f+q70I5C/j/eFpp80CzlB6Vc yYj2plH6aBVTVPkYvhNiMdqvniE+N0wg4i9tU5lTppG1FnOjMGkvec7GFaYMm3jyUGiO tfqY7CqPU6mO8yfwIUVf/meoG2a0lJQI7V42d9asy71Y/4qDKuEnVSwNK/ru8F6ty5av 2kUUnRGNckoDErkvl1ALd3BvUuphX5XLwuEgbFhB2v3EovL/R70/RMAvLnTaJrBr8gpQ SQ8w== X-Gm-Message-State: ALoCoQmfRj68mYwsoqPFr+7AVzGZI1KJPWqEERtldWQcC8D0IMnil2lUzuehTZn2PWX94Ed+s+78 X-Received: by 10.68.138.229 with SMTP id qt5mr177474pbb.62.1422347184649; Tue, 27 Jan 2015 00:26:24 -0800 (PST) Received: from ss-ubuntu.lan ([106.51.225.38]) by mx.google.com with ESMTPSA id l4sm783884pdj.47.2015.01.27.00.26.20 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 27 Jan 2015 00:26:23 -0800 (PST) From: Sumit Semwal To: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Cc: linaro-kernel@lists.linaro.org, robdclark@gmail.com, daniel@ffwll.ch, m.szyprowski@samsung.com, stanislawski.tomasz@googlemail.com, robin.murphy@arm.com, Sumit Semwal Subject: [RFCv3 2/2] dma-buf: add helpers for sharing attacher constraints with dma-parms Date: Tue, 27 Jan 2015 13:55:54 +0530 Message-Id: <1422347154-15258-2-git-send-email-sumit.semwal@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1422347154-15258-1-git-send-email-sumit.semwal@linaro.org> References: <1422347154-15258-1-git-send-email-sumit.semwal@linaro.org> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-PMX-Version: 6.0.0.2142326, Antispam-Engine: 2.7.2.2107409, Antispam-Data: 2015.1.27.81518 X-PMX-Spam: Gauge=IIIIIIII, Probability=8%, Report=' MULTIPLE_RCPTS 0.1, HTML_00_01 0.05, HTML_00_10 0.05, REFERENCES 0, URI_ENDS_IN_HTML 0, __ANY_URI 0, __CP_URI_IN_BODY 0, __FRAUD_BODY_WEBMAIL 0, __FRAUD_WEBMAIL 0, __HAS_FROM 0, __HAS_MSGID 0, __HAS_X_MAILER 0, __HAS_X_MAILING_LIST 0, __IN_REP_TO 0, __MIME_TEXT_ONLY 0, __MULTIPLE_RCPTS_CC_X2 0, __MULTIPLE_RCPTS_TO_X5 0, __REFERENCES 0, __SANE_MSGID 0, __STOCK_PHRASE_7 0, __SUBJ_ALPHA_END 0, __TO_MALFORMED_2 0, __TO_NO_NAME 0, __URI_NO_WWW 0, __URI_NS , __YOUTUBE_RCVD 0' Add some helpers to share the constraints of devices while attaching to the dmabuf buffer. At each attach, the constraints are calculated based on the following: - max_segment_size, max_segment_count, segment_boundary_mask from device_dma_parameters. In case the attaching device's constraints don't match up, attach() fails. At detach, the constraints are recalculated based on the remaining attached devices. Two helpers are added: - dma_buf_get_constraints - which gives the current constraints as calculated during each attach on the buffer till the time, - dma_buf_recalc_constraints - which recalculates the constraints for all currently attached devices for the 'paranoid' ones amongst us. The idea of this patch is largely taken from Rob Clark's RFC at https://lkml.org/lkml/2012/7/19/285, and the comments received on it. Cc: Rob Clark Signed-off-by: Sumit Semwal Reviewed-By: Maarten Lankhorst Acked-by: Marek Szyprowski --- v3: - Thanks to Russell's comment, remove dma_mask and coherent_dma_mask from constraints' calculation; has a nice side effect of letting us use device_dma_parameters directly to list constraints. - update the debugfs output to show constraint info as well. v2: split constraints-sharing and allocation helpers drivers/dma-buf/dma-buf.c | 126 +++++++++++++++++++++++++++++++++++++++++++++- include/linux/dma-buf.h | 7 +++ 2 files changed, 132 insertions(+), 1 deletion(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 5be225c2ba98..f363f1440803 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -264,6 +264,66 @@ static inline int is_dma_buf_file(struct file *file) return file->f_op == &dma_buf_fops; } +static inline void init_constraints(struct device_dma_parameters *cons) +{ + cons->max_segment_count = (unsigned int)-1; + cons->max_segment_size = (unsigned int)-1; + cons->segment_boundary_mask = (unsigned long)-1; +} + +/* + * calc_constraints - calculates if the new attaching device's constraints + * match, with the constraints of already attached devices; if yes, returns + * the constraints; else return ERR_PTR(-EINVAL) + */ +static int calc_constraints(struct device *dev, + struct device_dma_parameters *calc_cons) +{ + struct device_dma_parameters cons = *calc_cons; + + cons.max_segment_count = min(cons.max_segment_count, + dma_get_max_seg_count(dev)); + cons.max_segment_size = min(cons.max_segment_size, + dma_get_max_seg_size(dev)); + cons.segment_boundary_mask &= dma_get_seg_boundary(dev); + + if (!cons.max_segment_count || + !cons.max_segment_size || + !cons.segment_boundary_mask) { + pr_err("Dev: %s's constraints don't match\n", dev_name(dev)); + return -EINVAL; + } + + *calc_cons = cons; + + return 0; +} + +/* + * recalc_constraints - recalculates constraints for all attached devices; + * useful for detach() recalculation, and for dma_buf_recalc_constraints() + * helper. + * Returns recalculated constraints in recalc_cons, or error in the unlikely + * case when constraints of attached devices might have changed. + */ +static int recalc_constraints(struct dma_buf *dmabuf, + struct device_dma_parameters *recalc_cons) +{ + struct device_dma_parameters calc_cons; + struct dma_buf_attachment *attach; + int ret = 0; + + init_constraints(&calc_cons); + + list_for_each_entry(attach, &dmabuf->attachments, node) { + ret = calc_constraints(attach->dev, &calc_cons); + if (ret) + return ret; + } + *recalc_cons = calc_cons; + return 0; +} + /** * dma_buf_export_named - Creates a new dma_buf, and associates an anon file * with this buffer, so it can be exported. @@ -313,6 +373,9 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops, dmabuf->ops = ops; dmabuf->size = size; dmabuf->exp_name = exp_name; + + init_constraints(&dmabuf->constraints); + init_waitqueue_head(&dmabuf->poll); dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll; dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0; @@ -422,7 +485,7 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, struct device *dev) { struct dma_buf_attachment *attach; - int ret; + int ret = 0; if (WARN_ON(!dmabuf || !dev)) return ERR_PTR(-EINVAL); @@ -436,6 +499,9 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, mutex_lock(&dmabuf->lock); + if (calc_constraints(dev, &dmabuf->constraints)) + goto err_constraints; + if (dmabuf->ops->attach) { ret = dmabuf->ops->attach(dmabuf, dev, attach); if (ret) @@ -448,6 +514,7 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, err_attach: kfree(attach); +err_constraints: mutex_unlock(&dmabuf->lock); return ERR_PTR(ret); } @@ -470,6 +537,8 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) if (dmabuf->ops->detach) dmabuf->ops->detach(dmabuf, attach); + recalc_constraints(dmabuf, &dmabuf->constraints); + mutex_unlock(&dmabuf->lock); kfree(attach); } @@ -770,6 +839,56 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) } EXPORT_SYMBOL_GPL(dma_buf_vunmap); +/** + * dma_buf_get_constraints - get the *current* constraints of the dmabuf, + * as calculated during each attach(); returns error on invalid inputs + * + * @dmabuf: [in] buffer to get constraints of + * @constraints: [out] current constraints are returned in this + */ +int dma_buf_get_constraints(struct dma_buf *dmabuf, + struct device_dma_parameters *constraints) +{ + if (WARN_ON(!dmabuf || !constraints)) + return -EINVAL; + + mutex_lock(&dmabuf->lock); + *constraints = dmabuf->constraints; + mutex_unlock(&dmabuf->lock); + return 0; +} +EXPORT_SYMBOL_GPL(dma_buf_get_constraints); + +/** + * dma_buf_recalc_constraints - *recalculate* the constraints for the buffer + * afresh, from the list of currently attached devices; this could be useful + * cross-check the current constraints, for exporters that might want to be + * 'paranoid' about the device constraints. + * + * returns error on invalid inputs + * + * @dmabuf: [in] buffer to get constraints of + * @constraints: [out] recalculated constraints are returned in this + */ +int dma_buf_recalc_constraints(struct dma_buf *dmabuf, + struct device_dma_parameters *constraints) +{ + struct device_dma_parameters calc_cons; + int ret = 0; + + if (WARN_ON(!dmabuf || !constraints)) + return -EINVAL; + + mutex_lock(&dmabuf->lock); + ret = recalc_constraints(dmabuf, &calc_cons); + if (!ret) + *constraints = calc_cons; + + mutex_unlock(&dmabuf->lock); + return ret; +} +EXPORT_SYMBOL_GPL(dma_buf_recalc_constraints); + #ifdef CONFIG_DEBUG_FS static int dma_buf_describe(struct seq_file *s) { @@ -801,6 +920,11 @@ static int dma_buf_describe(struct seq_file *s) buf_obj->file->f_flags, buf_obj->file->f_mode, file_count(buf_obj->file), buf_obj->exp_name); + seq_printf(s, "\tConstraints: Seg Count: %08u, Seg Size: %08u", + buf_obj->constraints.max_segment_count, + buf_obj->constraints.max_segment_size); + seq_printf(s, " seg boundary mask: %08lx\n", + buf_obj->constraints.segment_boundary_mask); seq_puts(s, "\tAttached Devices:\n"); attach_count = 0; diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 694e1fe1c4b4..489ad9b2e5ae 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -34,6 +34,7 @@ #include struct device; +struct device_dma_parameters; struct dma_buf; struct dma_buf_attachment; @@ -116,6 +117,7 @@ struct dma_buf_ops { * @ops: dma_buf_ops associated with this buffer object. * @exp_name: name of the exporter; useful for debugging. * @list_node: node for dma_buf accounting and debugging. + * @constraints: calculated constraints of attached devices. * @priv: exporter specific private data for this buffer object. * @resv: reservation object linked to this dma-buf */ @@ -130,6 +132,7 @@ struct dma_buf { void *vmap_ptr; const char *exp_name; struct list_head list_node; + struct device_dma_parameters constraints; void *priv; struct reservation_object *resv; @@ -211,4 +214,8 @@ void *dma_buf_vmap(struct dma_buf *); void dma_buf_vunmap(struct dma_buf *, void *vaddr); int dma_buf_debugfs_create_file(const char *name, int (*write)(struct seq_file *)); + +int dma_buf_get_constraints(struct dma_buf *, struct device_dma_parameters *); +int dma_buf_recalc_constraints(struct dma_buf *, + struct device_dma_parameters *); #endif /* __DMA_BUF_H__ */