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authorArnd Bergmann <arnd@arndb.de>2021-09-08 15:18:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-08 15:32:34 -0700
commit5b1b561ba73c8ab9c98e5dfd14dc7ee47efb6530 (patch)
treeb8ebf18758abc3c1af1f04cd4a8150b3fd47448d /mm/migrate.c
parent5d700a0fd71ded7096b97f01d276efc1a6579613 (diff)
mm: simplify compat_sys_move_pages
The compat move_pages() implementation uses compat_alloc_user_space() for converting the pointer array. Moving the compat handling into the function itself is a bit simpler and lets us avoid the compat_alloc_user_space() call. Link: https://lkml.kernel.org/r/20210727144859.4150043-4-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/migrate.c')
-rw-r--r--mm/migrate.c45
1 files changed, 30 insertions, 15 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 24c2ff8fe4c0..2bc494875cea 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1900,6 +1900,23 @@ set_status:
mmap_read_unlock(mm);
}
+static int get_compat_pages_array(const void __user *chunk_pages[],
+ const void __user * __user *pages,
+ unsigned long chunk_nr)
+{
+ compat_uptr_t __user *pages32 = (compat_uptr_t __user *)pages;
+ compat_uptr_t p;
+ int i;
+
+ for (i = 0; i < chunk_nr; i++) {
+ if (get_user(p, pages32 + i))
+ return -EFAULT;
+ chunk_pages[i] = compat_ptr(p);
+ }
+
+ return 0;
+}
+
/*
* Determine the nodes of a user array of pages and store it in
* a user array of status.
@@ -1919,8 +1936,15 @@ static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages,
if (chunk_nr > DO_PAGES_STAT_CHUNK_NR)
chunk_nr = DO_PAGES_STAT_CHUNK_NR;
- if (copy_from_user(chunk_pages, pages, chunk_nr * sizeof(*chunk_pages)))
- break;
+ if (in_compat_syscall()) {
+ if (get_compat_pages_array(chunk_pages, pages,
+ chunk_nr))
+ break;
+ } else {
+ if (copy_from_user(chunk_pages, pages,
+ chunk_nr * sizeof(*chunk_pages)))
+ break;
+ }
do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);
@@ -2025,23 +2049,14 @@ SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE6(move_pages, pid_t, pid, compat_ulong_t, nr_pages,
- compat_uptr_t __user *, pages32,
+ compat_uptr_t __user *, pages,
const int __user *, nodes,
int __user *, status,
int, flags)
{
- const void __user * __user *pages;
- int i;
-
- pages = compat_alloc_user_space(nr_pages * sizeof(void *));
- for (i = 0; i < nr_pages; i++) {
- compat_uptr_t p;
-
- if (get_user(p, pages32 + i) ||
- put_user(compat_ptr(p), pages + i))
- return -EFAULT;
- }
- return kernel_move_pages(pid, nr_pages, pages, nodes, status, flags);
+ return kernel_move_pages(pid, nr_pages,
+ (const void __user *__user *)pages,
+ nodes, status, flags);
}
#endif /* CONFIG_COMPAT */