From 98aaaec4a150c39219a8aaa68c3adc6eed443ea8 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 14 Mar 2019 17:45:18 +0100 Subject: compat_ioctl: reimplement SG_IO handling There are two code locations that implement the SG_IO ioctl: the old sg.c driver, and the generic scsi_ioctl helper that is in turn used by multiple drivers. To eradicate the old compat_ioctl conversion handler for the SG_IO command, I implement a readable pair of put_sg_io_hdr() /get_sg_io_hdr() helper functions that can be used for both compat and native mode, and then I call this from both drivers. For the iovec handling, there is already a compat_import_iovec() function that can simply be called in place of import_iovec(). To avoid having to pass the compat/native state through multiple indirections, I mark the SG_IO command itself as compatible in fs/compat_ioctl.c and use in_compat_syscall() to figure out where we are called from. As a side-effect of this, the sg.c driver now also accepts the 32-bit sg_io_hdr format in compat mode using the read/write interface, not just ioctl. This should improve compatiblity with old 32-bit binaries, but it would break if any application intentionally passes the 64-bit data structure in compat mode here. Steffen Maier helped debug an issue in an earlier version of this patch. Cc: Steffen Maier Cc: linux-scsi@vger.kernel.org Cc: Doug Gilbert Cc: "James E.J. Bottomley" Cc: "Martin K. Petersen" Signed-off-by: Arnd Bergmann --- lib/iov_iter.c | 1 + 1 file changed, 1 insertion(+) (limited to 'lib/iov_iter.c') diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 639d5e7014c1..ffb52f2c0ef4 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1678,6 +1678,7 @@ ssize_t compat_import_iovec(int type, *iov = p == *iov ? NULL : p; return n; } +EXPORT_SYMBOL(compat_import_iovec); #endif int import_single_range(int rw, void __user *buf, size_t len, -- cgit v1.2.3