attribute_container_device_trigger invokes callbacks that may fail for one
or more classdevs, for instance, the transport_add_class_device callback,
called during transport creation, does memory allocation. This
information, though, is not propagated to upper layers, and any driver
using the attribute_container_device_trigger API will not know whether any,
some, or all callbacks succeeded.
This patch implements a safe version of this dispatcher, to either succeed
all the callbacks or revert to the original state.
Link: https://lore.kernel.org/r/20200106185817.640331-2-krisman@collabora.com
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Pull compat_ioctl cleanup from Arnd. Here's his description:
This series concludes the work I did for linux-5.5 on the compat_ioctl()
cleanup, killing off fs/compat_ioctl.c and block/compat_ioctl.c by moving
everything into drivers.
Overall this would be a reduction both in complexity and line count, but
as I'm also adding documentation the overall number of lines increases
in the end.
My plan was originally to keep the SCSI and block parts separate.
This did not work easily because of interdependencies: I cannot
do the final SCSI cleanup in a good way without first addressing the
CDROM ioctls, so this is one series that I hope could be merged through
either the block or the scsi git trees, or possibly both if you can
pull in the same branch.
The series comes in these steps:
1. clean up the sg v3 interface as suggested by Linus. I have
talked about this with Doug Gilbert as well, and he would
rebase his sg v4 patches on top of "compat: scsi: sg: fix v3
compat read/write interface"
2. Actually moving handlers out of block/compat_ioctl.c and
block/scsi_ioctl.c into drivers, mixed in with cleanup
patches
3. Document how to do this right. I keep getting asked about this,
and it helps to point to some documentation file.
The branch is based on another one that fixes a couple of bugs found
during the creation of this series.
Changes since v3:
https://lore.kernel.org/lkml/20200102145552.1853992-1-arnd@arndb.de/
- Move sr_compat_ioctl fixup to correct patch (Ben Hutchings)
- Add Reviewed-by tags
Changes since v2:
https://lore.kernel.org/lkml/20191217221708.3730997-1-arnd@arndb.de/
- Rebase to v5.5-rc4, which contains the earlier bugfixes
- Fix sr_block_compat_ioctl() error handling bug found by
Ben Hutchings
- Fix idecd_locked_compat_ioctl() compat_ptr() bug
- Don't try to handle HDIO_DRIVE_TASKFILE in drivers/ide
- More documentation improvements
Changes since v1:
https://lore.kernel.org/lkml/20191211204306.1207817-1-arnd@arndb.de/
- move out the bugfixes into a branch for itself
- clean up scsi sg driver further as suggested by Christoph Hellwig
- avoid some ifdefs by moving compat_ptr() out of asm/compat.h
- split out the blkdev_compat_ptr_ioctl function; bug spotted by
Ben Hutchings
- Improve formatting of documentation
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Documentation/process/botching-up-ioctls.rst was orignally written as
a blog post for DRM driver writers, so it it misses some points while
going into a lot of detail on others.
Try to provide a replacement that addresses typical issues across a wider
range of subsystems, and follows the style of the core-api documentation
better.
Many improvements to the document are suggested by Ben Hutchings
<ben.hutchings@codethink.co.uk>, Jonathan Corbet <corbet@lwn.net> and
Geert Uytterhoeven <geert@linux-m68k.org>.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Having separate implementations of blkdev_ioctl() often leads to these
getting out of sync, despite the comment at the top.
Since most of the ioctl commands are compatible, and we try very hard
not to add any new incompatible ones, move all the common bits into a
shared function and leave only the ones that are historically different
in separate functions for native/compat mode.
To deal with the compat_ptr() conversion, pass both the integer
argument and the pointer argument into the new blkdev_common_ioctl()
and make sure to always use the correct one of these.
blkdev_ioctl() is now only kept as a separate exported interfact
for drivers/char/raw.c, which lacks a compat_ioctl variant.
We should probably either move raw.c to staging if there are no
more users, or export blkdev_compat_ioctl() as well.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
There is no need to go through a compat_alloc_user_space()
copy any more, just wrap the function in a small helper that
works the same way for native and compat mode.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Having both in the same file allows a number of simplifications
to the compat path, and makes it more likely that changes to
the native path get applied to the compat version as well.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Most of the HDIO ioctls are only used by the obsolete drivers/ide
subsystem, these can be handled by changing ide_cmd_ioctl() to be aware
of compat mode and doing the correct transformations in place and using
it as both native and compat handlers for all drivers.
The SCSI drivers implementing the same commands are already doing
this in the drivers, so the compat_blkdev_driver_ioctl() function
is no longer needed now.
The BLKSECTSET and HDIO_GETGEO_BIG ioctls are not implemented
in any driver any more and no longer need any conversion.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The ata_sas_scsi_ioctl() function implements a number of HDIO_* commands
for SCSI devices, it is used by all libata drivers as well as a few
drivers that support SAS attached SATA drives.
The only command that is not safe for compat ioctls here is
HDIO_GET_32BIT. Change the implementation to check for in_compat_syscall()
in order to do both cases correctly, and change all callers to use it
as both native and compat callback pointers, including the indirect
callers through sas_ioctl and ata_scsi_ioctl.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
There is no need for the special cases for the cdrom ioctls any more now,
so make sure that each cdrom driver has a .compat_ioctl() callback and
calls cdrom_compat_ioctl() directly there.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Now that both native and compat ioctl syscalls are
in the same file, a couple of simplifications can
be made, bringing the implementation closer together:
- do_vfs_ioctl(), ioctl_preallocate(), and compat_ioctl_preallocate()
can become static, allowing the compiler to optimize better
- slightly update the coding style for consistency between
the functions.
- rather than listing each command in two switch statements
for the compat case, just call a single function that has
all the common commands.
As a side-effect, FS_IOC_RESVSP/FS_IOC_RESVSP64 are now available
to x86 compat tasks, along with FS_IOC_RESVSP_32/FS_IOC_RESVSP64_32.
This is harmless for i386 emulation, and can be considered a bugfix
for x32 emulation, which never supported these in the past.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The rest of the fs/compat_ioctl.c file is no longer useful now,
so move the actual syscall as planned.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Each driver calling scsi_ioctl() gets an equivalent compat_ioctl()
handler that implements the same commands by calling scsi_compat_ioctl().
The scsi_cmd_ioctl() and scsi_cmd_blk_ioctl() functions are compatible
at this point, so any driver that calls those can do so for both native
and compat mode, with the argument passed through compat_ptr().
With this, we can remove the entries from fs/compat_ioctl.c. The new
code is larger, but should be easier to maintain and keep updated with
newly added commands.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Rather than relying on fs/compat_ioctl.c, this adds support
for a compat_ioctl() callback in the ide-floppy driver directly,
which lets it translate the scsi commands.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
bsg_ioctl() calls into scsi_cmd_ioctl() for a couple of generic commands
and relies on fs/compat_ioctl.c to handle it correctly in compat mode.
Adding a private compat_ioctl() handler avoids that round-trip and lets
us get rid of the generic emulation once this is done.
Note that bsg implements an SG_IO command that is different from the
other drivers and does not need emulation.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
In order to move the compat handling for SCSI ioctl commands out of
fs/compat_ioctl.c into the individual drivers, we need a helper function
first to match the native ioctl handler called by sd, sr, st, etc.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Various block drivers implement the CDROMMULTISESSION,
CDROM_GET_CAPABILITY, and CDROMEJECT ioctl commands, relying on the
block layer to handle compat_ioctl mode for them.
Move this into the drivers directly as a preparation for simplifying
the block layer later.
When only integer arguments or no arguments are passed, the
same handler can be used for .ioctl and .compat_ioctl, and
when only pointer arguments are passed, the newly added
blkdev_compat_ptr_ioctl can be used.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Gabriel Krisman Bertazi
Nick Black
Stanley Chu
Colin Ian King
YueHaibing
Martin K. Petersen
Arnd Bergmann