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| author | Liam R. Howlett <Liam.Howlett@Oracle.com> | 2024-08-30 06:00:59 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-04 06:15:52 +0200 |
| commit | 224c1c702c08ca4d874690991f02e5b08c816e5b (patch) | |
| tree | d8cac2ba41ff7cb42d3cbb206c32f16cf7ef5a53 /mm/mmap.c | |
| parent | ipc/shm, mm: drop do_vma_munmap() (diff) | |
| download | linux-224c1c702c08ca4d874690991f02e5b08c816e5b.tar.xz linux-224c1c702c08ca4d874690991f02e5b08c816e5b.zip | |
mm: move may_expand_vm() check in mmap_region()
The may_expand_vm() check requires the count of the pages within the
munmap range. Since this is needed for accounting and obtained later, the
reodering of ma_expand_vm() to later in the call stack, after the vma
munmap struct (vms) is initialised and the gather stage is potentially
run, will allow for a single loop over the vmas. The gather sage does not
commit any work and so everything can be undone in the case of a failure.
The MAP_FIXED page count is available after the vms_gather_munmap_vmas()
call, so use it instead of looping over the vmas twice.
Link: https://lkml.kernel.org/r/20240830040101.822209-20-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 15 |
1 files changed, 4 insertions, 11 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 6485f2300692..fc726c4e98be 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1376,17 +1376,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr, pgoff_t vm_pgoff; int error = -ENOMEM; VMA_ITERATOR(vmi, mm, addr); - unsigned long nr_pages, nr_accounted; - - nr_pages = count_vma_pages_range(mm, addr, end, &nr_accounted); - - /* - * Check against address space limit. - * MAP_FIXED may remove pages of mappings that intersects with requested - * mapping. Account for the pages it would unmap. - */ - if (!may_expand_vm(mm, vm_flags, pglen - nr_pages)) - return -ENOMEM; /* Find the first overlapping VMA */ vma = vma_find(&vmi, end); @@ -1410,6 +1399,10 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma_iter_next_range(&vmi); } + /* Check against address space limit. */ + if (!may_expand_vm(mm, vm_flags, pglen - vms.nr_pages)) + goto abort_munmap; + /* * Private writable mapping: check memory availability */ |