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Subject[PATCH -mm 1/5][AIO] - Rework compat_sys_io_submit

compat_sys_io_submit() cleanup


Cleanup compat_sys_io_submit by duplicating some of the native syscall
logic in the compat layer and directly calling io_submit_one() instead
of fooling the syscall into thinking it is called from a native 64-bit
caller.

This is needed for the completion notification patch to avoid having
to rewrite each iocb on the caller stack for sys_io_submit() to find the
sigevents.



compat.c | 61 +++++++++++++++++++++++++++++++++++--------------------------
1 file changed, 35 insertions(+), 26 deletions(-)

Signed-off-by: Sébastien Dugué <sebastien.dugue@bull.net>

Index: linux-2.6.19-rc6-mm2/fs/compat.c
===================================================================
--- linux-2.6.19-rc6-mm2.orig/fs/compat.c 2006-11-28 12:49:40.000000000
+0100 +++ linux-2.6.19-rc6-mm2/fs/compat.c 2006-11-28 12:51:35.000000000
+0100 @@ -642,40 +642,49 @@ out:
return ret;
}

-static inline long
-copy_iocb(long nr, u32 __user *ptr32, struct iocb __user * __user *ptr64)
+asmlinkage long
+compat_sys_io_submit(aio_context_t ctx_id, int nr, u32 __user *iocb)
{
- compat_uptr_t uptr;
+ struct kioctx *ctx;
+ long ret = 0;
int i;

- for (i = 0; i < nr; ++i) {
- if (get_user(uptr, ptr32 + i))
- return -EFAULT;
- if (put_user(compat_ptr(uptr), ptr64 + i))
- return -EFAULT;
- }
- return 0;
-}
+ if (unlikely(nr < 0))
+ return -EINVAL;

-#define MAX_AIO_SUBMITS (PAGE_SIZE/sizeof(struct iocb *))
+ if (unlikely(!access_ok(VERIFY_READ, iocb, (nr * sizeof(u32)))))
+ return -EFAULT;

-asmlinkage long
-compat_sys_io_submit(aio_context_t ctx_id, int nr, u32 __user *iocb)
-{
- struct iocb __user * __user *iocb64;
- long ret;
+ ctx = lookup_ioctx(ctx_id);

- if (unlikely(nr < 0))
+ if (unlikely(!ctx))
return -EINVAL;
+ for (i=0; i<nr; i++) {
+ compat_uptr_t uptr;
+ struct iocb __user *user_iocb;
+ struct iocb tmp;

- if (nr > MAX_AIO_SUBMITS)
- nr = MAX_AIO_SUBMITS;
-
- iocb64 = compat_alloc_user_space(nr * sizeof(*iocb64));
- ret = copy_iocb(nr, iocb, iocb64);
- if (!ret)
- ret = sys_io_submit(ctx_id, nr, iocb64);
- return ret;
+ if (get_user(uptr, iocb + i)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ user_iocb = compat_ptr(uptr);
+
+ if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
+ ret = -EFAULT;
+ break;
+ }
+
+ ret = io_submit_one(ctx, user_iocb, &tmp);
+
+ if (ret)
+ break;
+ }
+
+ put_ioctx(ctx);
+
+ return i? i: ret;
}

struct compat_ncp_mount_data {
-
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