linux-kernel - [091/244] iommu/amd: Make sure iommu->need

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Date:	Wed, 28 Sep 2011 15:00:55 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Joerg Roedel <joerg.roedel@....com>
Subject: [091/244] iommu/amd: Make sure iommu->need_sync contains correct value

3.0-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Joerg Roedel <joerg.roedel@....com>

commit f1ca1512e765337a7c09eb875eedef8ea4e07654 upstream.

The value is only set to true but never set back to false,
which causes to many completion-wait commands to be sent to
hardware. Fix it with this patch.

Signed-off-by: Joerg Roedel <joerg.roedel@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 arch/x86/kernel/amd_iommu.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -531,7 +531,9 @@ static void build_inv_all(struct iommu_c
  * Writes the command to the IOMMUs command buffer and informs the
  * hardware about the new command.
  */
-static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
+static int iommu_queue_command_sync(struct amd_iommu *iommu,
+				    struct iommu_cmd *cmd,
+				    bool sync)
 {
 	u32 left, tail, head, next_tail;
 	unsigned long flags;
@@ -565,13 +567,18 @@ again:
 	copy_cmd_to_buffer(iommu, cmd, tail);
 
 	/* We need to sync now to make sure all commands are processed */
-	iommu->need_sync = true;
+	iommu->need_sync = sync;
 
 	spin_unlock_irqrestore(&iommu->lock, flags);
 
 	return 0;
 }
 
+static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
+{
+	return iommu_queue_command_sync(iommu, cmd, true);
+}
+
 /*
  * This function queues a completion wait command into the command
  * buffer of an IOMMU
@@ -587,7 +594,7 @@ static int iommu_completion_wait(struct
 
 	build_completion_wait(&cmd, (u64)&sem);
 
-	ret = iommu_queue_command(iommu, &cmd);
+	ret = iommu_queue_command_sync(iommu, &cmd, false);
 	if (ret)
 		return ret;
 


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