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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 <Liam.Howlett@oracle.com>
Cc: Li Zetao <lizetao1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2023-01-20 11:26:38 -05:00 committed by Andrew Morton
parent b373037fa9
commit cc8d1b097d
1 changed files with 19 additions and 28 deletions
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29
mm/mmap.c
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@ -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;
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)
if (!arch_validate_flags(vma->vm_flags))
goto close_and_free_vma;
else if (vma->vm_file)
goto unmap_and_free_vma;
else
goto free_vma;
}
if (vma_iter_prealloc(&vmi)) {
error = -ENOMEM;
if (file)
if (vma_iter_prealloc(&vmi))
goto close_and_free_vma;
else if (vma->vm_file)
goto unmap_and_free_vma;
else
goto 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;
/* Undo any partial mapping done by a device driver. */
unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, vma->vm_end);
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: