This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now that all MTD drivers have moved to the mtd_ooblayout_ops model we can
safely remove the struct nand_ecclayout definition, and all the remaining
places where it was still used.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

ECC layout definitions are currently exposed using the nand_ecclayout
struct which embeds oobfree and eccpos arrays with predefined size.
This approach was acceptable when NAND chips were providing relatively
small OOB regions, but MLC and TLC now provide OOB regions of several
hundreds of bytes, which implies a non negligible overhead for everybody
even those who only need to support legacy NANDs.

Create an mtd_ooblayout_ops interface providing the same functionality
(expose the ECC and oobfree layout) without the need for this huge
structure.

The mtd->ecclayout is now deprecated and should be replaced by the
equivalent mtd_ooblayout_ops. In the meantime we provide a wrapper around
the ->ecclayout field to ease migration to this new model.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The mtd_ooblayout_xxx() helper functions have been added to avoid direct
accesses to the ecclayout field, and thus ease for future reworks.
Use these helpers in all places where the oobfree[] and eccpos[] arrays
where directly accessed.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

After a bit of poking around wondering why my 32-bit user-space can't
seem to send a proper ioctl(BLKPG) to an MTD on my 64-bit kernel
(ARM64), I noticed that struct blkpg_ioctl_arg is actually pretty
unsuitable for use in the ioctl() ABI, due to its use of raw pointers,
and its lack of alignment/packing restrictions (32-bit arch'es tend to
pack the 4 fields into 4 32-bit words, whereas 64-bit arch'es would add
padding after the third int, and make this 6 32-bit words).

Anyway, this means BLKPG deserves some special compat_ioctl handling. Do
the conversion in a small shim for MTD.

block/compat_ioctl.c already has compat support for the block subsystem,
but it does so by a re-marshalling data to/from user-space (see
compat_blkpg_ioctl()). Personally, I think this approach is cleaner.

Tested only on MTD, with an ARM32 user space on an ARM64 kernel.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Since "BDI: Provide backing device capability information [try #3]" the
backing_dev_info structure also provides flags for the kind of mmap
operation available in a nommu environment, which is entirely unrelated
to it's original purpose.

Introduce a new nommu-only file operation to provide this information to
the nommu mmap code instead.  Splitting this from the backing_dev_info
structure allows to remove lots of backing_dev_info instance that aren't
otherwise needed, and entirely gets rid of the concept of providing a
backing_dev_info for a character device.  It also removes the need for
the mtd_inodefs filesystem.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Noticed by Coverity as a potential security issue.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

On m68k, where access_ok() doesn't cast the address parameter:

drivers/mtd/mtdchar.c: In function 'mtdchar_write_ioctl':
drivers/mtd/mtdchar.c:575:4: warning: passing argument 2 of 'access_ok' makes pointer from integer without a cast [enabled by default]
arch/m68k/include/asm/uaccess_mm.h:17:90: note: expected 'const void *' but argument is of type '__u64'
drivers/mtd/mtdchar.c:576:4: warning: passing argument 2 of 'access_ok' makes pointer from integer without a cast [enabled by default]
arch/m68k/include/asm/uaccess_mm.h:17:90: note: expected 'const void *' but argument is of type '__u64'

The address parameter of access_ok() is really a userspace pointer.
On most architectures, access_ok() is a macro that casts the address
parameter, hiding issues in its users.

Move around and use the existing usr_data and usr_oob temporary variables
to kill the warnings. Add a few "consts", and make more use of the
temporaries while we're at it.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

If a write to one time programmable memory (OTP) hits the end of this
memory area, no more data can be written. The count variable in
mtdchar_write() in drivers/mtd/mtdchar.c is not decreased anymore.
We are trapped in the loop forever, mtdchar_write() will never return
in this case.

The desired behavior of a write in such a case is described in [1]:
- Try to write as much data as possible, truncate the write to fit into
  the available memory and return the number of bytes that actually
  have been written.
- If no data could be written at all, return -ENOSPC.

This patch fixes the behavior of OTP write if there is not enough space
for all data:

1) mtd_write_user_prot_reg() in drivers/mtd/mtdcore.c is modified to
   return -ENOSPC if no data could be written at all.
2) mtdchar_write() is modified to handle -ENOSPC correctly. Exit if a
   write returned -ENOSPC and yield the correct return value, either
   then number of bytes that could be written, or -ENOSPC, if no data
   could be written at all.

Furthermore the patch harmonizes the behavior of the OTP memory write
in drivers/mtd/devices/mtd_dataflash.c with the other implementations
and the requirements from [1]. Instead of returning -EINVAL if the data
does not fit into the OTP memory, we try to write as much data as
possible/truncate the write.

[1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/write.html

Signed-off-by: Christian Riesch <christian.riesch@omicron.at>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Signed-off-by: Christian Riesch <christian.riesch@omicron.at>
Cc: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>