From patchwork Thu Nov 29 15:04:17 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Paul X-Patchwork-Id: 10704749 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 904AD13A4 for ; Thu, 29 Nov 2018 15:04:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6DDEE2F4C5 for ; Thu, 29 Nov 2018 15:04:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6269A2F493; Thu, 29 Nov 2018 15:04:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6651E2F493 for ; Thu, 29 Nov 2018 15:04:45 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9CEF76E45D; Thu, 29 Nov 2018 15:04:44 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-yw1-xc43.google.com (mail-yw1-xc43.google.com [IPv6:2607:f8b0:4864:20::c43]) by gabe.freedesktop.org (Postfix) with ESMTPS id D22166E45D for ; Thu, 29 Nov 2018 15:04:41 +0000 (UTC) Received: by mail-yw1-xc43.google.com with SMTP id i20so876543ywc.5 for ; Thu, 29 Nov 2018 07:04:41 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=1lW80fT5J0SpL5OO6GS5m9fbtjOuKX24K5P1Z7ah7BU=; b=UR9usY2rZ/upMabN1iqi15niB6Myu/DhAPp3Xu20k4FT8viNIEQg9BsXBhPc12U+AS 4oxXnr0FgORmmowDE/4ntl6REjOwT5lfqKV7iijG7T2kR4zzKKThQVllgRbBYa4lB2t0 Mnprq+r6UNgONIBXZhumHVXkVb5C3FC0U7G2rDHT5eOce0Ofq5DYytT3F41Y2AqqYDvT tco5Vo/jGWxC7lHu32DK05j6n23JYUwyXVFrJVE8GMEupEuaJYGSZez6UBhIDnS2HsDW Cd28YA/j+FCM0jz5OK2HQT3ahAxJbZfkGbOdo9UdLJ90pX9EwUUPS93d3akTzl8Q1DYQ pY5Q== X-Gm-Message-State: AA+aEWZjVHLglQoWSKiXCWB+sfWiJ/pgezIh7DAj0Qw885DJfdIuhRlm +RIEQIcDlblKnt1O3EAvjXLEOQIe6YoUQQ== X-Google-Smtp-Source: AFSGD/X0VKjCv+aoIgqmnEotwwLmxnY/M4myxHllQhJ+dSER6zT9kzHO2BPvXFKXNWa6mmmoJMyb5g== X-Received: by 2002:a81:6b57:: with SMTP id g84mr1702730ywc.108.1543503880766; Thu, 29 Nov 2018 07:04:40 -0800 (PST) Received: from rosewood.cam.corp.google.com ([2620:0:1013:11:ad55:b1db:adfe:3b9f]) by smtp.gmail.com with ESMTPSA id r20sm2434656ywa.13.2018.11.29.07.04.39 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 29 Nov 2018 07:04:39 -0800 (PST) From: Sean Paul To: dri-devel@lists.freedesktop.org Subject: [PATCH v2 4/4] drm: Add DRM_MODESET_LOCK_BEGIN/END helpers Date: Thu, 29 Nov 2018 10:04:17 -0500 Message-Id: <20181129150423.239081-4-sean@poorly.run> X-Mailer: git-send-email 2.20.0.rc0.387.gc7a69e6b6c-goog In-Reply-To: <20181129150423.239081-1-sean@poorly.run> References: <20181129150423.239081-1-sean@poorly.run> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Maxime Ripard , David Airlie , Sean Paul , Sean Paul Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Sean Paul This patch adds a couple of helpers to remove the boilerplate involved in grabbing all of the modeset locks. I've also converted the obvious cases in drm core to use the helpers. The only remaining instance of drm_modeset_lock_all_ctx() is in drm_framebuffer. It's complicated by the state clear that occurs on deadlock. ATM, there's no way to inject code in the deadlock path with the helpers, so it's unfit for conversion. Changes in v2: - Relocate ret argument to the end of the list (Daniel) - Incorporate Daniel's doc suggestions (Daniel) Suggested-by: Daniel Vetter Reviewed-by: Daniel Vetter Signed-off-by: Sean Paul --- drivers/gpu/drm/drm_atomic_helper.c | 51 +++++-------------------- drivers/gpu/drm/drm_color_mgmt.c | 14 +------ drivers/gpu/drm/drm_crtc.c | 15 ++------ drivers/gpu/drm/drm_modeset_lock.c | 6 +++ drivers/gpu/drm/drm_plane.c | 16 ++------ include/drm/drm_modeset_lock.h | 59 +++++++++++++++++++++++++++++ 6 files changed, 83 insertions(+), 78 deletions(-) diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 43e129eee244a..5140534315ea1 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -3124,23 +3124,13 @@ void drm_atomic_helper_shutdown(struct drm_device *dev) struct drm_modeset_acquire_ctx ctx; int ret; - drm_modeset_acquire_init(&ctx, 0); - while (1) { - ret = drm_modeset_lock_all_ctx(dev, &ctx); - if (!ret) - ret = __drm_atomic_helper_disable_all(dev, &ctx, true); - - if (ret != -EDEADLK) - break; - - drm_modeset_backoff(&ctx); - } + DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, ret); + ret = __drm_atomic_helper_disable_all(dev, &ctx, true); if (ret) DRM_ERROR("Disabling all crtc's during unload failed with %i\n", ret); - drm_modeset_drop_locks(&ctx); - drm_modeset_acquire_fini(&ctx); + DRM_MODESET_LOCK_ALL_END(ctx, ret); } EXPORT_SYMBOL(drm_atomic_helper_shutdown); @@ -3175,14 +3165,7 @@ struct drm_atomic_state *drm_atomic_helper_suspend(struct drm_device *dev) struct drm_atomic_state *state; int err; - drm_modeset_acquire_init(&ctx, 0); - -retry: - err = drm_modeset_lock_all_ctx(dev, &ctx); - if (err < 0) { - state = ERR_PTR(err); - goto unlock; - } + DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, err); state = drm_atomic_helper_duplicate_state(dev, &ctx); if (IS_ERR(state)) @@ -3196,13 +3179,10 @@ struct drm_atomic_state *drm_atomic_helper_suspend(struct drm_device *dev) } unlock: - if (PTR_ERR(state) == -EDEADLK) { - drm_modeset_backoff(&ctx); - goto retry; - } + DRM_MODESET_LOCK_ALL_END(ctx, err); + if (err) + return ERR_PTR(err); - drm_modeset_drop_locks(&ctx); - drm_modeset_acquire_fini(&ctx); return state; } EXPORT_SYMBOL(drm_atomic_helper_suspend); @@ -3276,22 +3256,11 @@ int drm_atomic_helper_resume(struct drm_device *dev, drm_mode_config_reset(dev); - drm_modeset_acquire_init(&ctx, 0); - while (1) { - err = drm_modeset_lock_all_ctx(dev, &ctx); - if (err) - goto out; + DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, err); - err = drm_atomic_helper_commit_duplicated_state(state, &ctx); -out: - if (err != -EDEADLK) - break; - - drm_modeset_backoff(&ctx); - } + err = drm_atomic_helper_commit_duplicated_state(state, &ctx); - drm_modeset_drop_locks(&ctx); - drm_modeset_acquire_fini(&ctx); + DRM_MODESET_LOCK_ALL_END(ctx, err); drm_atomic_state_put(state); return err; diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c index 581cc37882230..07dcf47daafe2 100644 --- a/drivers/gpu/drm/drm_color_mgmt.c +++ b/drivers/gpu/drm/drm_color_mgmt.c @@ -255,11 +255,7 @@ int drm_mode_gamma_set_ioctl(struct drm_device *dev, if (crtc_lut->gamma_size != crtc->gamma_size) return -EINVAL; - drm_modeset_acquire_init(&ctx, 0); -retry: - ret = drm_modeset_lock_all_ctx(dev, &ctx); - if (ret) - goto out; + DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, ret); size = crtc_lut->gamma_size * (sizeof(uint16_t)); r_base = crtc->gamma_store; @@ -284,13 +280,7 @@ int drm_mode_gamma_set_ioctl(struct drm_device *dev, crtc->gamma_size, &ctx); out: - if (ret == -EDEADLK) { - drm_modeset_backoff(&ctx); - goto retry; - } - drm_modeset_drop_locks(&ctx); - drm_modeset_acquire_fini(&ctx); - + DRM_MODESET_LOCK_ALL_END(ctx, ret); return ret; } diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index af4b94ce8e942..42cdb41816438 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -599,11 +599,8 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data, plane = crtc->primary; mutex_lock(&crtc->dev->mode_config.mutex); - drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE); -retry: - ret = drm_modeset_lock_all_ctx(crtc->dev, &ctx); - if (ret) - goto out; + DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, + DRM_MODESET_ACQUIRE_INTERRUPTIBLE, ret); if (crtc_req->mode_valid) { /* If we have a mode we need a framebuffer. */ @@ -768,13 +765,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data, fb = NULL; mode = NULL; - if (ret == -EDEADLK) { - ret = drm_modeset_backoff(&ctx); - if (!ret) - goto retry; - } - drm_modeset_drop_locks(&ctx); - drm_modeset_acquire_fini(&ctx); + DRM_MODESET_LOCK_ALL_END(ctx, ret); mutex_unlock(&crtc->dev->mode_config.mutex); return ret; diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c index 8a5100685875a..51f534db91070 100644 --- a/drivers/gpu/drm/drm_modeset_lock.c +++ b/drivers/gpu/drm/drm_modeset_lock.c @@ -56,6 +56,10 @@ * drm_modeset_drop_locks(ctx); * drm_modeset_acquire_fini(ctx); * + * For convenience this control flow is implemented in + * DRM_MODESET_LOCK_ALL_BEGIN() and DRM_MODESET_LOCK_ALL_END() for the case + * where all modeset locks need to be taken through drm_modeset_lock_all_ctx(). + * * If all that is needed is a single modeset lock, then the &struct * drm_modeset_acquire_ctx is not needed and the locking can be simplified * by passing a NULL instead of ctx in the drm_modeset_lock() call or @@ -383,6 +387,8 @@ EXPORT_SYMBOL(drm_modeset_unlock); * Locks acquired with this function should be released by calling the * drm_modeset_drop_locks() function on @ctx. * + * See also: DRM_MODESET_LOCK_ALL_BEGIN() and DRM_MODESET_LOCK_ALL_END() + * * Returns: 0 on success or a negative error-code on failure. */ int drm_modeset_lock_all_ctx(struct drm_device *dev, diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c index 679455e368298..5f650d8fc66b7 100644 --- a/drivers/gpu/drm/drm_plane.c +++ b/drivers/gpu/drm/drm_plane.c @@ -767,11 +767,8 @@ static int setplane_internal(struct drm_plane *plane, struct drm_modeset_acquire_ctx ctx; int ret; - drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE); -retry: - ret = drm_modeset_lock_all_ctx(plane->dev, &ctx); - if (ret) - goto fail; + DRM_MODESET_LOCK_ALL_BEGIN(plane->dev, ctx, + DRM_MODESET_ACQUIRE_INTERRUPTIBLE, ret); if (drm_drv_uses_atomic_modeset(plane->dev)) ret = __setplane_atomic(plane, crtc, fb, @@ -782,14 +779,7 @@ static int setplane_internal(struct drm_plane *plane, crtc_x, crtc_y, crtc_w, crtc_h, src_x, src_y, src_w, src_h, &ctx); -fail: - if (ret == -EDEADLK) { - ret = drm_modeset_backoff(&ctx); - if (!ret) - goto retry; - } - drm_modeset_drop_locks(&ctx); - drm_modeset_acquire_fini(&ctx); + DRM_MODESET_LOCK_ALL_END(ctx, ret); return ret; } diff --git a/include/drm/drm_modeset_lock.h b/include/drm/drm_modeset_lock.h index a685d1bb21f26..a308f2d6496f0 100644 --- a/include/drm/drm_modeset_lock.h +++ b/include/drm/drm_modeset_lock.h @@ -130,4 +130,63 @@ void drm_warn_on_modeset_not_all_locked(struct drm_device *dev); int drm_modeset_lock_all_ctx(struct drm_device *dev, struct drm_modeset_acquire_ctx *ctx); +/** + * DRM_MODESET_LOCK_ALL_BEGIN - Helper to acquire modeset locks + * @dev: drm device + * @ctx: local modeset acquire context, will be dereferenced + * @flags: DRM_MODESET_ACQUIRE_* flags to pass to drm_modeset_acquire_init() + * @ret: local ret/err/etc variable to track error status + * + * Use these macros to simplify grabbing all modeset locks using a local + * context. This has the advantage of reducing boilerplate, but also properly + * checking return values where appropriate. + * + * Any code run between BEGIN and END will be holding the modeset locks. + * + * This must be paired with DRM_MODESET_LOCK_ALL_END(). We will jump back and + * forth between the labels on deadlock and error conditions. + * + * Drivers can acquire additional modeset locks. If any lock acquisition + * fails, the control flow needs to jump to DRM_MODESET_LOCK_ALL_END() with + * the @ret parameter containing the return value of drm_modeset_lock(). + * + * Returns: + * The only possible value of ret immediately after DRM_MODESET_LOCK_ALL_BEGIN() + * is 0, so no error checking is necessary + */ +#define DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, flags, ret) \ + drm_modeset_acquire_init(&ctx, flags); \ +modeset_lock_retry: \ + ret = drm_modeset_lock_all_ctx(dev, &ctx); \ + if (ret) \ + goto modeset_lock_fail; + +/** + * DRM_MODESET_LOCK_ALL_END - Helper to release and cleanup modeset locks + * @ctx: local modeset acquire context, will be dereferenced + * @ret: local ret/err/etc variable to track error status + * + * The other side of DRM_MODESET_LOCK_ALL_BEGIN(). It will bounce back to BEGIN + * if ret is -EDEADLK. + * + * It's important that you use the same ret variable for begin and end so + * deadlock conditions are properly handled. + * + * Returns: + * ret will be untouched unless it is -EDEADLK on entry. That means that if you + * successfully acquire the locks, ret will be whatever your code sets it to. If + * there is a deadlock or other failure with acquire or backoff, ret will be set + * to that failure. In both of these cases the code between BEGIN/END will not + * be run, so the failure will reflect the inability to grab the locks. + */ +#define DRM_MODESET_LOCK_ALL_END(ctx, ret) \ +modeset_lock_fail: \ + if (ret == -EDEADLK) { \ + ret = drm_modeset_backoff(&ctx); \ + if (!ret) \ + goto modeset_lock_retry; \ + } \ + drm_modeset_drop_locks(&ctx); \ + drm_modeset_acquire_fini(&ctx); + #endif /* DRM_MODESET_LOCK_H_ */