git: dfabdacb279c - main - iommu_gas: Avoid double unmapping on error

[Alan Cox]

The branch main has been updated by alc:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=dfabdacb279ca603d008a0e7e952c5c59ac51da4

commit dfabdacb279ca603d008a0e7e952c5c59ac51da4
Author:     Alan Cox <a...@freebsd.org>
AuthorDate: 2022-07-21 06:53:54 +0000
Commit:     Alan Cox <a...@freebsd.org>
CommitDate: 2022-07-21 07:00:46 +0000

    iommu_gas: Avoid double unmapping on error
    
    In the extremely unlikely case that the iommu_gas_map_region() call in
    bus_dma_iommu_load_ident() failed, we would attempt to unmap the failed
    entry twice, first in iommu_gas_map_region(), and a second time in the
    caller.  Once is enough, and twice is problematic because it leads to a
    second RB_REMOVE call on the same tree node.  Like it or not, RB_TREE
    does not handle that possibility.
    
    Reviewed by:    kib
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D35869
---
 sys/dev/iommu/busdma_iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/dev/iommu/busdma_iommu.c b/sys/dev/iommu/busdma_iommu.c
index 10e7476b35eb..67e82fe43e58 100644
--- a/sys/dev/iommu/busdma_iommu.c
+++ b/sys/dev/iommu/busdma_iommu.c
@@ -1055,7 +1055,7 @@ bus_dma_iommu_load_ident(bus_dma_tag_t dmat, bus_dmamap_t 
map1,
                TAILQ_INSERT_TAIL(&map->map_entries, entry, dmamap_link);
                IOMMU_DMAMAP_UNLOCK(map);
        } else {
-               iommu_domain_unload_entry(entry, true);
+               iommu_gas_free_entry(domain, entry);
        }
        for (i = 0; i < atop(length); i++)
                vm_page_putfake(ma[i]);