6.13-stable review patch. If anyone has any objections, please let me know.
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From: Ilia Levi ilia.levi@intel.com
[ Upstream commit 4d79a1266d4cc3c967bc8823502466cad1ac8514 ]
The irq.enabled flag was protected by a spin lock (irq.lock). By making it atomic we no longer need to wait for the spin lock in irq handlers. This will become especially useful for MSI-X irq handlers to prevent lock contention between different interrupts.
Signed-off-by: Ilia Levi ilia.levi@intel.com Reviewed-by: Rodrigo Vivi rodrigo.vivi@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20241210173506.202150-1-ilia.l... Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com Stable-dep-of: 0c455f3a1229 ("drm/xe: Fix error handling in xe_irq_install()") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/xe/display/ext/i915_irq.c | 13 +--------- drivers/gpu/drm/xe/xe_device_types.h | 2 +- drivers/gpu/drm/xe/xe_irq.c | 29 ++++++----------------- 3 files changed, 9 insertions(+), 35 deletions(-)
diff --git a/drivers/gpu/drm/xe/display/ext/i915_irq.c b/drivers/gpu/drm/xe/display/ext/i915_irq.c index a7dbc6554d694..ac4cda2d81c7a 100644 --- a/drivers/gpu/drm/xe/display/ext/i915_irq.c +++ b/drivers/gpu/drm/xe/display/ext/i915_irq.c @@ -53,18 +53,7 @@ void gen2_irq_init(struct intel_uncore *uncore, struct i915_irq_regs regs,
bool intel_irqs_enabled(struct xe_device *xe) { - /* - * XXX: i915 has a racy handling of the irq.enabled, since it doesn't - * lock its transitions. Because of that, the irq.enabled sometimes - * is not read with the irq.lock in place. - * However, the most critical cases like vblank and page flips are - * properly using the locks. - * We cannot take the lock in here or run any kind of assert because - * of i915 inconsistency. - * But at this point the xe irq is better protected against races, - * although the full solution would be protecting the i915 side. - */ - return xe->irq.enabled; + return atomic_read(&xe->irq.enabled); }
void intel_synchronize_irq(struct xe_device *xe) diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h index b9ea455d6f59f..09068ea7349a8 100644 --- a/drivers/gpu/drm/xe/xe_device_types.h +++ b/drivers/gpu/drm/xe/xe_device_types.h @@ -345,7 +345,7 @@ struct xe_device { spinlock_t lock;
/** @irq.enabled: interrupts enabled on this device */ - bool enabled; + atomic_t enabled; } irq;
/** @ttm: ttm device */ diff --git a/drivers/gpu/drm/xe/xe_irq.c b/drivers/gpu/drm/xe/xe_irq.c index b7995ebd54abd..32547b6a6d1cb 100644 --- a/drivers/gpu/drm/xe/xe_irq.c +++ b/drivers/gpu/drm/xe/xe_irq.c @@ -348,12 +348,8 @@ static irqreturn_t xelp_irq_handler(int irq, void *arg) unsigned long intr_dw[2]; u32 identity[32];
- spin_lock(&xe->irq.lock); - if (!xe->irq.enabled) { - spin_unlock(&xe->irq.lock); + if (!atomic_read(&xe->irq.enabled)) return IRQ_NONE; - } - spin_unlock(&xe->irq.lock);
master_ctl = xelp_intr_disable(xe); if (!master_ctl) { @@ -417,12 +413,8 @@ static irqreturn_t dg1_irq_handler(int irq, void *arg)
/* TODO: This really shouldn't be copied+pasted */
- spin_lock(&xe->irq.lock); - if (!xe->irq.enabled) { - spin_unlock(&xe->irq.lock); + if (!atomic_read(&xe->irq.enabled)) return IRQ_NONE; - } - spin_unlock(&xe->irq.lock);
master_tile_ctl = dg1_intr_disable(xe); if (!master_tile_ctl) { @@ -644,12 +636,8 @@ static irqreturn_t vf_mem_irq_handler(int irq, void *arg) struct xe_tile *tile; unsigned int id;
- spin_lock(&xe->irq.lock); - if (!xe->irq.enabled) { - spin_unlock(&xe->irq.lock); + if (!atomic_read(&xe->irq.enabled)) return IRQ_NONE; - } - spin_unlock(&xe->irq.lock);
for_each_tile(tile, xe, id) xe_memirq_handler(&tile->memirq); @@ -674,10 +662,9 @@ static void irq_uninstall(void *arg) struct pci_dev *pdev = to_pci_dev(xe->drm.dev); int irq;
- if (!xe->irq.enabled) + if (!atomic_xchg(&xe->irq.enabled, 0)) return;
- xe->irq.enabled = false; xe_irq_reset(xe);
irq = pci_irq_vector(pdev, 0); @@ -724,7 +711,7 @@ int xe_irq_install(struct xe_device *xe) return err; }
- xe->irq.enabled = true; + atomic_set(&xe->irq.enabled, 1);
xe_irq_postinstall(xe);
@@ -744,9 +731,7 @@ void xe_irq_suspend(struct xe_device *xe) { int irq = to_pci_dev(xe->drm.dev)->irq;
- spin_lock_irq(&xe->irq.lock); - xe->irq.enabled = false; /* no new irqs */ - spin_unlock_irq(&xe->irq.lock); + atomic_set(&xe->irq.enabled, 0); /* no new irqs */
synchronize_irq(irq); /* flush irqs */ xe_irq_reset(xe); /* turn irqs off */ @@ -762,7 +747,7 @@ void xe_irq_resume(struct xe_device *xe) * 1. no irq will arrive before the postinstall * 2. display is not yet resumed */ - xe->irq.enabled = true; + atomic_set(&xe->irq.enabled, 1); xe_irq_reset(xe); xe_irq_postinstall(xe); /* turn irqs on */