[PATCH] dmaengine: idxd: Move dma_free_coherent() out of spinlocked context

[Rex Zhang <rex.zhang@xxxxxxxxx>]

Task may be rescheduled within dma_free_coherent(). So dma_free_coherent()
can't be called between spin_lock() and spin_unlock() to avoid Call Trace:
    Call Trace:
    <TASK>
    dump_stack_lvl+0x37/0x50
    __might_resched+0x16a/0x1c0
    vunmap+0x2c/0x70
    __iommu_dma_free+0x96/0x100
    idxd_device_evl_free+0xd5/0x100 [idxd]
    device_release_driver_internal+0x197/0x200
    unbind_store+0xa1/0xb0
    kernfs_fop_write_iter+0x120/0x1c0
    vfs_write+0x2d3/0x400
    ksys_write+0x63/0xe0
    do_syscall_64+0x44/0xa0
    entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Move it out of the context.

Fixes: 244da66cda35 ("dmaengine: idxd: setup event log configuration")
Signed-off-by: Rex Zhang <rex.zhang@xxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Reviewed-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
---
 drivers/dma/idxd/device.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 8f754f922217..fa0f880beae6 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -802,6 +802,9 @@ static int idxd_device_evl_setup(struct idxd_device *idxd)
 
 static void idxd_device_evl_free(struct idxd_device *idxd)
 {
+	void *evl_log;
+	unsigned int evl_log_size;
+	dma_addr_t evl_dma;
 	union gencfg_reg gencfg;
 	union genctrl_reg genctrl;
 	struct device *dev = &idxd->pdev->dev;
@@ -822,11 +825,15 @@ static void idxd_device_evl_free(struct idxd_device *idxd)
 	iowrite64(0, idxd->reg_base + IDXD_EVLCFG_OFFSET);
 	iowrite64(0, idxd->reg_base + IDXD_EVLCFG_OFFSET + 8);
 
-	dma_free_coherent(dev, evl->log_size, evl->log, evl->dma);
 	bitmap_free(evl->bmap);
+	evl_log = evl->log;
+	evl_log_size = evl->log_size;
+	evl_dma = evl->dma;
 	evl->log = NULL;
 	evl->size = IDXD_EVL_SIZE_MIN;
 	spin_unlock(&evl->lock);
+
+	dma_free_coherent(dev, evl_log_size, evl_log, evl_dma);
 }
 
 static void idxd_group_config_write(struct idxd_group *group)
-- 
2.25.1