linux-kernel - [PATCH 4.9 027/101] powerpc/powernv/ioda2: Remove redundant free of TCE pages

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Message-Id: <20180701160758.232618323@linuxfoundation.org>
Date:   Sun,  1 Jul 2018 18:21:13 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Alexey Kardashevskiy <aik@...abs.ru>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.9 027/101] powerpc/powernv/ioda2: Remove redundant free of TCE pages

4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Alexey Kardashevskiy <aik@...abs.ru>

commit 98fd72fe82527fd26618062b60cfd329451f2329 upstream.

When IODA2 creates a PE, it creates an IOMMU table with it_ops::free
set to pnv_ioda2_table_free() which calls pnv_pci_ioda2_table_free_pages().

Since iommu_tce_table_put() calls it_ops::free when the last reference
to the table is released, explicit call to pnv_pci_ioda2_table_free_pages()
is not needed so let's remove it.

This should fix double free in the case of PCI hotuplug as
pnv_pci_ioda2_table_free_pages() does not reset neither
iommu_table::it_base nor ::it_size.

This was not exposed by SRIOV as it uses different code path via
pnv_pcibios_sriov_disable().

IODA1 does not inialize it_ops::free so it does not have this issue.

Fixes: c5f7700bbd2e ("powerpc/powernv: Dynamically release PE")
Cc: stable@...r.kernel.org # v4.8+
Signed-off-by: Alexey Kardashevskiy <aik@...abs.ru>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/powerpc/platforms/powernv/pci-ioda.c |    1 -
 1 file changed, 1 deletion(-)

--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -3424,7 +3424,6 @@ static void pnv_pci_ioda2_release_pe_dma
 		WARN_ON(pe->table_group.group);
 	}

-	pnv_pci_ioda2_table_free_pages(tbl);
 	iommu_free_table(tbl, "pnv");
 }