Patch "iommu/amd: Do not call sleep while holding spinlock" has been added to the 5.18-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    iommu/amd: Do not call sleep while holding spinlock

to the 5.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iommu-amd-do-not-call-sleep-while-holding-spinlock.patch
and it can be found in the queue-5.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3b28e88484d591f4932d44b48c58ae2377e04a2b
Author: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Date:   Sun Mar 13 21:43:21 2022 -0500

    iommu/amd: Do not call sleep while holding spinlock
    
    [ Upstream commit 5edde870d3283edeaa27ab62ac4fac5ee8cae35a ]
    
    Smatch static checker warns:
            drivers/iommu/amd/iommu_v2.c:133 free_device_state()
            warn: sleeping in atomic context
    
    Fixes by storing the list of struct device_state in a temporary
    list, and then free the memory after releasing the spinlock.
    
    Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
    Fixes: 9f968fc70d85 ("iommu/amd: Improve amd_iommu_v2_exit()")
    Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
    Link: https://lore.kernel.org/r/20220314024321.37411-1-suravee.suthikulpanit@xxxxxxx
    Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/iommu/amd/iommu_v2.c b/drivers/iommu/amd/iommu_v2.c
index e56b137ceabd..afb3efd565b7 100644
--- a/drivers/iommu/amd/iommu_v2.c
+++ b/drivers/iommu/amd/iommu_v2.c
@@ -956,6 +956,7 @@ static void __exit amd_iommu_v2_exit(void)
 {
 	struct device_state *dev_state, *next;
 	unsigned long flags;
+	LIST_HEAD(freelist);
 
 	if (!amd_iommu_v2_supported())
 		return;
@@ -975,11 +976,20 @@ static void __exit amd_iommu_v2_exit(void)
 
 		put_device_state(dev_state);
 		list_del(&dev_state->list);
-		free_device_state(dev_state);
+		list_add_tail(&dev_state->list, &freelist);
 	}
 
 	spin_unlock_irqrestore(&state_lock, flags);
 
+	/*
+	 * Since free_device_state waits on the count to be zero,
+	 * we need to free dev_state outside the spinlock.
+	 */
+	list_for_each_entry_safe(dev_state, next, &freelist, list) {
+		list_del(&dev_state->list);
+		free_device_state(dev_state);
+	}
+
 	destroy_workqueue(iommu_wq);
 }