From be5c7a90753fb9f74c867f74489abe822ffb4b26 Mon Sep 17 00:00:00 2001 From: Damien Lespiau Date: Tue, 15 Oct 2013 18:55:41 +0100 Subject: [PATCH] drm/i915: Only one open() allowed on pipe CRC result files It doesn't really make sense to have two processes dequeueing the CRC values at the same time. Forbid that usage. Signed-off-by: Damien Lespiau Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_debugfs.c | 16 ++++++++++++++++ drivers/gpu/drm/i915/i915_drv.h | 1 + 2 files changed, 17 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 5137f8f97b8a..826ebcead3c4 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -1768,6 +1768,15 @@ struct pipe_crc_info { static int i915_pipe_crc_open(struct inode *inode, struct file *filep) { + struct pipe_crc_info *info = inode->i_private; + struct drm_i915_private *dev_priv = info->dev->dev_private; + struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe]; + + if (!atomic_dec_and_test(&pipe_crc->available)) { + atomic_inc(&pipe_crc->available); + return -EBUSY; /* already open */ + } + filep->private_data = inode->i_private; return 0; @@ -1775,6 +1784,12 @@ static int i915_pipe_crc_open(struct inode *inode, struct file *filep) static int i915_pipe_crc_release(struct inode *inode, struct file *filep) { + struct pipe_crc_info *info = inode->i_private; + struct drm_i915_private *dev_priv = info->dev->dev_private; + struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe]; + + atomic_inc(&pipe_crc->available); /* release the device */ + return 0; } @@ -2684,6 +2699,7 @@ void intel_display_crc_init(struct drm_device *dev) for (i = 0; i < INTEL_INFO(dev)->num_pipes; i++) { struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[i]; + atomic_set(&pipe_crc->available, 1); init_waitqueue_head(&pipe_crc->wq); } } diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 7408f1184347..9aeddc0b27b8 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1232,6 +1232,7 @@ struct intel_pipe_crc_entry { #define INTEL_PIPE_CRC_ENTRIES_NR 128 struct intel_pipe_crc { + atomic_t available; /* exclusive access to the device */ struct intel_pipe_crc_entry *entries; enum intel_pipe_crc_source source; atomic_t head, tail;