From ed4577fc2b8671a63bc56e525c6bed13e4a3c182 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 5 Jun 2019 21:45:56 +0200 Subject: drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit 1882018a70e06376234133e69ede9dd743b4dbd9 ] We can be called from any context, we need to be prepared. Noticed this while hacking on vkms, which calls this function from a normal worker. Which really upsets lockdep. Cc: Rodrigo Siqueira Cc: Tomeu Vizoso Cc: Emil Velikov Cc: Benjamin Gaignard Reviewed-by: Benjamin Gaignard Reviewed-by: Ville Syrjälä Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20190605194556.16744-1-daniel.vetter@ffwll.ch Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_debugfs_crc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/drm_debugfs_crc.c') diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c index f9e26dda56d6..021813b20e97 100644 --- a/drivers/gpu/drm/drm_debugfs_crc.c +++ b/drivers/gpu/drm/drm_debugfs_crc.c @@ -359,8 +359,9 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, struct drm_crtc_crc *crc = &crtc->crc; struct drm_crtc_crc_entry *entry; int head, tail; + unsigned long flags; - spin_lock(&crc->lock); + spin_lock_irqsave(&crc->lock, flags); /* Caller may not have noticed yet that userspace has stopped reading */ if (!crc->entries) { @@ -385,7 +386,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1); crc->head = head; - spin_unlock(&crc->lock); + spin_unlock_irqrestore(&crc->lock, flags); wake_up_interruptible(&crc->wq); -- cgit v1.2.3 From d06e92cfb34eaea6215ebcec55d6270f5657ff3c Mon Sep 17 00:00:00 2001 From: Maarten Lankhorst Date: Wed, 18 Apr 2018 14:51:21 +0200 Subject: drm/crc: Only report a single overflow when a CRC fd is opened MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit a012024571d98e2e4bf29a9168fb7ddc44b7ab86 ] This reduces the amount of spam when you debug a CRC reading program. Signed-off-by: Maarten Lankhorst [mlankhorst: Change bool overflow to was_overflow (Ville)] Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20180418125121.72081-1-maarten.lankhorst@linux.intel.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_debugfs_crc.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/drm_debugfs_crc.c') diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c index 021813b20e97..f689c75474e5 100644 --- a/drivers/gpu/drm/drm_debugfs_crc.c +++ b/drivers/gpu/drm/drm_debugfs_crc.c @@ -139,6 +139,7 @@ static int crtc_crc_data_count(struct drm_crtc_crc *crc) static void crtc_crc_cleanup(struct drm_crtc_crc *crc) { kfree(crc->entries); + crc->overflow = false; crc->entries = NULL; crc->head = 0; crc->tail = 0; @@ -373,8 +374,14 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, tail = crc->tail; if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) { + bool was_overflow = crc->overflow; + + crc->overflow = true; spin_unlock(&crc->lock); - DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n"); + + if (!was_overflow) + DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n"); + return -ENOBUFS; } -- cgit v1.2.3 From 51c843bfb1f90c8005e19cec651a7ca4e035c2f2 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 6 Jun 2019 23:15:44 +0200 Subject: drm/crc-debugfs: Also sprinkle irqrestore over early exits MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit d99004d7201aa653658ff2390d6e516567c96ebc ] I. was. blind. Caught with vkms, which has some really slow crc computation function. Fixes: 1882018a70e0 ("drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry") Cc: Rodrigo Siqueira Cc: Tomeu Vizoso Cc: Emil Velikov Cc: Benjamin Gaignard Cc: Ville Syrjälä Reviewed-by: Emil Velikov Reviewed-by: Benjamin Gaignard Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20190606211544.5389-1-daniel.vetter@ffwll.ch Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_debugfs_crc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/drm_debugfs_crc.c') diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c index f689c75474e5..2901b7944068 100644 --- a/drivers/gpu/drm/drm_debugfs_crc.c +++ b/drivers/gpu/drm/drm_debugfs_crc.c @@ -366,7 +366,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, /* Caller may not have noticed yet that userspace has stopped reading */ if (!crc->entries) { - spin_unlock(&crc->lock); + spin_unlock_irqrestore(&crc->lock, flags); return -EINVAL; } @@ -377,7 +377,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, bool was_overflow = crc->overflow; crc->overflow = true; - spin_unlock(&crc->lock); + spin_unlock_irqrestore(&crc->lock, flags); if (!was_overflow) DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n"); -- cgit v1.2.3