From cc8d1b097de78bd25b7b1ed32018b21cecbf3f6c Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Fri, 20 Jan 2023 11:26:38 -0500 Subject: [PATCH] mmap: clean up mmap_region() unrolling Move logic of unrolling to the error path as apposed to duplicating it within the function body. This reduces the potential of missing an update to one path when making changes. Link: https://lkml.kernel.org/r/20230120162650.984577-38-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Cc: Li Zetao Signed-off-by: Andrew Morton --- mm/mmap.c | 45 ++++++++++++++++++--------------------------- 1 file changed, 18 insertions(+), 27 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index f61e45c..95ea613a 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2601,12 +2601,11 @@ cannot_expand: * Expansion is handled above, merging is handled below. * Drivers should not alter the address of the VMA. */ - if (WARN_ON((addr != vma->vm_start))) { - error = -EINVAL; + error = -EINVAL; + if (WARN_ON((addr != vma->vm_start))) goto close_and_free_vma; - } - vma_iter_set(&vmi, addr); + vma_iter_set(&vmi, addr); /* * If vm_flags changed after call_mmap(), we should try merge * vma again as we may succeed this time. @@ -2653,25 +2652,13 @@ cannot_expand: } /* Allow architectures to sanity-check the vm_flags */ - if (!arch_validate_flags(vma->vm_flags)) { - error = -EINVAL; - if (file) - goto close_and_free_vma; - else if (vma->vm_file) - goto unmap_and_free_vma; - else - goto free_vma; - } + error = -EINVAL; + if (!arch_validate_flags(vma->vm_flags)) + goto close_and_free_vma; - if (vma_iter_prealloc(&vmi)) { - error = -ENOMEM; - if (file) - goto close_and_free_vma; - else if (vma->vm_file) - goto unmap_and_free_vma; - else - goto free_vma; - } + error = -ENOMEM; + if (vma_iter_prealloc(&vmi)) + goto close_and_free_vma; if (vma->vm_file) i_mmap_lock_write(vma->vm_file->f_mapping); @@ -2730,14 +2717,18 @@ expanded: return addr; close_and_free_vma: - if (vma->vm_ops && vma->vm_ops->close) + if (file && vma->vm_ops && vma->vm_ops->close) vma->vm_ops->close(vma); + + if (file || vma->vm_file) { unmap_and_free_vma: - fput(vma->vm_file); - vma->vm_file = NULL; + fput(vma->vm_file); + vma->vm_file = NULL; - /* Undo any partial mapping done by a device driver. */ - unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, vma->vm_end); + /* Undo any partial mapping done by a device driver. */ + unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, + vma->vm_end); + } if (file && (vm_flags & VM_SHARED)) mapping_unmap_writable(file->f_mapping); free_vma: -- 2.7.4