If the "write" file operation handler, `comedi_write()` is passed 0 for
the amount to write, some error conditions are currently skipped and the
function just returns 0. Change it to check those error conditions and
return an error value if appropriate. The trickiest case is the check
for when the previously set up asynchronous command has terminated with
an error. In that case, `-EPIPE` is returned (as it is for a write of
non-zero length) and the subdevice gets marked as non-busy.
A zero-length write that returns 0 has no other effects, in particular,
it does not cause the subdevice to be marked as non-busy.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In order to perform a "write" file operation, an asynchronous COMEDI
command in the "write" direction needs to have been set up by the
current file object on the COMEDI "write" subdevice associated with the
file object. If there is a "write" subdevice, but a command has not
been set up by the file object (or is has been set-up in the wrong
direction), `comedi_write()` currently returns one of two error values
`-EINVAL` or `-EACCES`. `-EACCES` is returned if the command was set up
by a different subdevice, or somewhat randomly, if a COMEDI
"instruction" is currently being processed. `-EINVAL` is returned in
other cases. Simplify it by returning `-EINVAL` for all these cases.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The "write" file operation handler, `comedi_write()` returns an error
for pretty much any condition that prevents a "write" going ahead. One
of the conditions that prevents a "write" going ahead is that no
asynchronous command has been set up, but that currently results in a
return value of 0 (unless COMEDI instructions are being processed or an
asynchronous command has been set up by a different file object).
Change it to return `-EINVAL` in this case.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_write()` copies data from the user buffer to the acquisition
data buffer, which is cyclic, using a single call to `copy_from_user()`.
It currently avoids having to deal with wraparound of the cyclic buffer
by limiting the amount it copies (and the amount returned to the user).
Change it to deal with the wraparound using two calls to
`copy_from_user()` if necessary.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
At one point in `comedi_write()`, the variable `n` gets assigned to the
minimum of the parameter `nbytes` and the amount of writeable buffer
space. The way that is done currently is unsafe in the unlikely case
that `nbytes` exceeds `UINT_MAX`, so fix it.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In `comedi_write()`, the `n` and `m` variables are of type `int`.
Change them to `unsigned int` as they are used to measure a positive
number of bytes. The `count` variable is also of type `int` and holds
the returned number of bytes written. Change it to type `ssize_t` to
match the function's return type.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_write()` is the handler for the "write" file operation for
COMEDI devices. It mostly runs without using the main mutex of the
COMEDI device, but uses the `attach_lock` rw_semaphore to protect
against the COMEDI device becoming "detached". A file object can write
data for a COMEDI asynchonous command if it initiated the command. The
COMEDI subdevice is marked as busy when the command is started. At some
point, the "write" handler detects that the command has terminated and
so marks the subdevice as non-busy.
In order to mark the subdevice as non-busy, the "write" handler needs to
release the `attach_lock` rw_semaphore and `acquire the main `mutex`.
There is a vulnerable point between the two, so it checks that the
device is still attached after acquiring the mutex. However, it does
not currently check that the conditions for becoming non-busy still
hold. Add some more checks that the subdevice is still busy with a
command initiated by the same file object, and that the command is in
the correct direction (in case the subdevice supports both "read" and
"write").
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rearrange the code in `comedi_write()` to reduce the amount of
indentation. The code never reiterates the `while` loop once `count`
has become non-zero, so we can check that in the `while` condition to
save an indentation level. (Note that `nbytes` has been checked to be
non-zero before entering the loop, so we can remove that check.) Move
the code that makes the subdevice "become non-busy" outside the `while`
loop, using a new flag variable `become_nonbusy` to decide whether it
needs to be done. This simplifies the wait queue handling so there is a
single place where the task is removed from the wait queue, and we can
remove the `on_wait_queue` flag variable.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the "read" file operation handler, `comedi_read()` is passed 0 for
the amount to read, some error conditions are currently skipped and the
function just returns 0. Change it to check those error conditions and
return an error value if appropriate. The trickiest case is the check
for when the previously set up asynchronous command has terminated with
an error. In that case, `-EPIPE` is returned (as it is for a read of
non-zero length) and the subdevice gets marked as non-busy.
A zero-length read that returns 0 has no other effects, in particular,
it does not cause the subdevice to be marked as non-busy, and the return
value does not indicate an "end-of-file" condition.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In order to perform a "read" file operation, an asynchronous COMEDI
command in the "read" direction needs to have been set up by the current
file object on the COMEDI "read" subdevice associated with the file
object. If there is a "read" subdevice, but a command has not been set
up by the file object (or is has been set-up in the wrong direction),
`comedi_read()` currently returns one of two error values `-EINVAL` or
`-EACCES`. `-EACCES` is returned if the command was set up by a
different subdevice, or somewhat randomly, if a COMEDI "instruction" is
currently being processed. `-EINVAL` is returned in other cases.
Simplify it by returning `-EINVAL` for all these cases.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The "read" file operation handler, `comedi_read()` returns an error for
pretty much any condition that prevents a "read" going ahead. One of
the conditions that prevents a "read" going ahead is that no
asynchronous command has been set up, but that currently results in a
return value of 0 (unless COMEDI instructions are being processed or an
asynchronous command has been set up by a different file object).
Change it to return `-EINVAL` in this case.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_read()` initializes `retval` to 0. The other `retval = 0`
assignments are superfluous, so remove them.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_read()` copies data from the acquisition data buffer, which is
cyclic, to the user buffer using a single call to `copy_to_user()`. It
currently avoids having to deal with wraparound of the cyclic buffer by
limiting the amount it copies (and the amount returned to the user).
Change it to deal with the wraparound using two calls to
`copy_to_user()` if necessary.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
At one point in `comedi_read()`, the variable `n` gets assigned to the
minimum of the parameter `nbytes` and the amount of readable buffer
space `m`. The way that is done currently is unsafe in the unlikely
case that `nbytes` exceeds `UINT_MAX`, so fix it.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In `comedi_read()`, the `n` and `m` variables are of type `int`. Change
them to `unsigned int` as they are used to measure a positive number of
bytes. The `count` variable is also of type `int` and holds the
returned number of bytes. Change it to type `ssize_t` to match the
function's return type.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_read()` is the handler for the "read" file operation for COMEDI
devices. It mostly runs without using the main mutex of the COMEDI
device, but uses the `attach_lock` rwsemaphore to protect against the
COMEDI device becoming "detached". A file object can read data
resulting from a COMEDI asynchonous command if it initiated the command.
The COMEDI subdevice is marked as busy when the command is started. At
some point, the "read" handler detects that the command has terminated
and all available data has been read and so marks the subdevice as
non-busy.
In order to mark the subdevice as non-busy, the "read" handler needs to
release the `attach_lock` rwsemaphore and `acquire the main `mutex`.
There is a vulnerable point between the two, so it checks that the
device is still attached after acquiring the mutex. However, it does
not currently check that the conditions for becoming non-busy still
hold. Add some more checks that the subdevice is still busy with a
command initiated by the same file object, that command is in the correct
direction (in case the subdevice supports both "read" and "write"), that
command has terminated, and has no data available to be read.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If an asynchronous "read" command is no longer running but the subdevice
is still busy, it becomes non-busy once there is no more data available
in the buffer. Some or all of the data written to the buffer might not
have been "munged" yet, and it cannot be read until it has been munged
by the writer. However, since the command is no longer running, we
cannot expect any remaining unmunged data to get munged so we should
ignore it. Call `comedi_buf_read_n_available()` to check the amount of
munged data available to be read, replacing the call to
`comedi_buf_n_bytes_ready()` which checked the amount of written (but
possibly not yet munged) data available to be read. This affects both
the "read" file operation (done in `comedi_read()`) and the
`COMEDI_BUFINFO` ioctl handling (done in `do_bufinfo_ioctl()`). (The
latter is used when data is transferred directly through the mmapped
buffer instead of via the "read" file operation.)
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If a COMEDI subdevice is busy handling an asynchronous command in the
"read" direction, then after the command has terminated itself, the
"read" file operation handler, `comedi_read()` should keep the subdevice
busy until all available data has been read and it has returned 0 to
indicate an "end-of-file" condition. Currently, it has a bug where it
can mark the subdevice as non-busy even when returning a non-zero count.
The bug is slightly hidden because the next "read" will return 0 because
the subdevice is no longer busy. Fix it by checking the return count is
0 before deciding to mark the subdevice as non-busy.
The call to `comedi_is_subdevice_idle()` is superfluous as the
`become_nonbusy` variable will have been set to `true` when considering
becoming non-busy. Strictly speaking, checking the return count is
superfluous too, as `become_nonbusy` doesn't get set to `true` unless
the count is 0, but check the return count anyway to make the intention
clearer.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The main mutex in a comedi device can get held for quite a while when
processing comedi instructions, so for performance reasons, the "read"
and "write" file operations do not use it; they use use the
`attach_lock` rwsemaphore to protect against the comedi device becoming
detached at an inopportune moment. Do the same for the "poll" file
operation.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, the "poll" file operation checks if an asynchronous "read"
(or "write" command is active on the "read" (or "write" subdevice, but
does not consider whether the command was started from the file object
being polled. Since that is the only file object able to read (or
write) data, take it into consideration.
With this change, if no read (or write) command is running on the
subdevice, or it is started by a different file object, the file object
is marked as readable (or writeable) regardless, but the read (or write)
file operation will return an error.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When handling the "poll" file operation and checking for `POLLOUT`,
don't allocate space from the buffer for writing, just check that space
is available for writing. That check is done after checking that an
asynchronous "write" command is running on the subdevice. Allocating
the buffer space before checking a "write" command is running can cause
problems if the subdevice supports commands in either direction and
currently has an active "read" command.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Comedi subdevices that support asynchronous acquisition commands have a
wait queue head used for blocking reads or writes and for the poll file
operation. The comedi device may have several subdevices that support
"read" and/or "write" commands, but each open file object has at most
one "read" subdevice and one "write" subdevice. It's possible (though
rare) for those to be the same subdevice if the subdevice supports
commands in either direction. In that case, the "poll" file operation
doesn't really need to do a `poll_wait()` on the same subdevice twice.
Although harmless, it wastes a poll table entry. Check for that, and
avoid it.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
n this file, function names are otherwise used as pointers without &.
A simplified version of the Coccinelle semantic patch that makes this
change is as follows:
// <smpl>
@r@
identifier f;
@@
f(...) { ... }
@@
identifier r.f;
@@
- &f
+ f
// </smpl>
Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adjust the kernel-doc in this file for consistency of capitalization and
punctuation. Make more use of the special kernel-doc markers for
parameter names, constant names, etc. Use the correct kernel-doc tag
for the return values sections.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The comment before the `COMEDI_SRF_...` macros starts with a kernel-doc
mark but isn't valid kernel-doc. There isn't a kernel-doc template for
a group of macro constants. These macros are all private anyway, so
don't really need to be in kernel-doc. Just change it to a normal
comment.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With two exceptions (drm/qxl and drm/radeon) all vm_operations_struct
structs should be constant.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This function is only called by comedi_cleanup_board_minors() and the
'minor' parameter will always be < COMEDI_NUM_BOARD_MINORS.
For aesthetics, absorb the function and remove the unnecessary BUG_ON().
Split the comedi_clear_board_minor() out to clarify that the return value
is a comedi_device pointer.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This function is only called by comedi_dev_get_from_minor() and the 'minor'
value will always be < COMEDI_NUM_BOARD_MINORS. Remove the unnecessary
BUG_ON().
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers should not crash the kernel.
This function is only called by comedi_device_detach_cleanup() and the
s->minor will always be valid or the device wouldn't have attached in
the first place.
Leave the checks for safety in accessing the comedi_subdevice_minor_table
array but remove the BUG_ON() calls.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The BUG_ON() checks in this function are not necessary.
comedi_cleanup_board_minors() clears all the entries in the
comedi_board_minor_table array and will call comedi_device_cleanup()
for all attached devices. comedi_device_cleanup() will then
clear the entries in the comedi_subdevice_minor_table array with
comedi_free_subdevice_minor().
Remove the BUG_ON(), drivers should not crash the kernel.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The BUG_ON() checks in comedi_subdevice_from_minor() and
comedi_dev_get_from_subdevice_minor() are not necessary.
The 'minor' numbers for a given comedi driver are setup by
comedi_dev_get_from_subdevice_minor() and will always be in
the correct range.
Drivers should not crash the kernel, remove the BUG_ON() checks.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fixes the checkpatch.pl warning:
WARNING: ENOSYS means 'invalid syscall nr' and nothing else
try_module_get fails when the reference count of the module is not
allowed to be incremented ,and hence -ENXIO is returned indicating
no device or address.
[IA - combined two of santhosh's changes to the error return value!]
Signed-off-by: santhosh pai <santhosh.pai88@yahoo.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the "comedi" module has been loaded with the
"comedi_num_legacy_minors" module parameter set to a non-zero value,
some reserved comedi devices get created. These can be attached to a
low-level comedi driver using the `COMEDI_DEVCONFIG` ioctl command,
which checks for the `CAP_SYS_ADMIN` capability. Of course, the comedi
device needs to be opened before the ioctl command can be sent. If the
comedi device is unattached, `comedi_open()` currently requires the
`CAP_NET_ADMIN` capability. It makes more sense to just require the
`CAP_SYS_ADMIN` capability here, so change it.
For the curious, commit a8f80e8ff9 ("Networking: use CAP_NET_ADMIN
when deciding to call request_module") changed this capability from
`CAP_SYS_MODULE` to `CAP_NET_ADMIN`, even though it doesn't seem
relevant here. The original `CAP_SYS_MODULE` capability was due to the
function having some code to request a module using a "char-major-%i-%i"
alias, but that was never compiled in and was removed by commit
f30f2c2d41 ("staging: comedi: remove check for CONFIG_KMOD").
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch removes commented code.This was a checkpatch warning.
Signed-off-by: Hari Prasath Gujulan Elango <hgujulan@visteon.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The `COMEDI_SRF_...` macros define flag combinations in the `runflags`
member of `struct comedi_subdevice`. They are only used directly in
"comedi_fops.c", so move them to there.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The `COMEDI_SRF_FREE_SPRIV` flag in the `runflags` member of `struct
comedi_subdevice` indicates that the memory pointed to by the `private`
member can be automatically freed by the comedi core on subdevice
clean-up (when the low-level comedi device is being "detached"). the
flag doesn't really belong in `runflags`, but it was somewhere
convenient to keep it without having to add a new member to the
structure.
Rather than access the `COMEDI_SRF_FREE_SPRIV` flag directly, use some
new wrapper functions:
* comedi_can_auto_free_spriv(s) - checks whether the subdevice's
`s->private` points to memory that can be freed automatically.
* comedi_set_spriv_auto_free(s) - marks the subdevice as having a
`s->private` that points to memory that can be freed automatically.
Export `comedi_set_spriv_auto_free()` for use by the low-level comedi
driver modules, in particular the "amplc_dio200_common" module.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_event()` is called from low-level drivers to handle comedi
asynchronous command event flags. As a safety check, it checks the
subdevice's "run" flags to make sure an asynchronous command is running.
It can also change the run flags to mark the command as no longer
running (possibly also marking it as terminated with an error).
Checking the runflags and modifying them involves two uses of the
subdevice's spin-lock. It seems better to do it with a single use of
the spin-lock. This also avoids possible interactions with
`do_become_nonbusy()`.
Acquire the subdevice's spin-lock at the start of `comedi_event()` and
release it near the end, before a possible call to `kill_fasync()` (but
after it's parameter values have been determined).
Add and make use of few new inline helper functions:
* `__comedi_clear_subdevice_runflags()` -- clears some run flags without
using the spin-lock
* `__comedi_set_subdevice_runflags()` -- sets some run flags without
using the spin-lock
* `__comedi_get_subdevice_runflags()` -- a spin-lockless version of
`comedi_get_subdevice_runflags()
* `__comedi_is_subdevice_running()` -- a spin-lockless version of
* `comedi_is_subdevice_running()`
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_event()` is called from low-level drivers to handle comedi
asynchronous command event flags. Some events cause waiting tasks to be
woken up, and a `SIGIO` signal to be sent via `kill_fasync()`. The
signal code is `POLL_OUT` if the subdevice supports commands in the
"write" direction, or `POLL_IN` for the "read" direction. If the
subdevice supports commands in either direction, it sends two `SIGIO`
signals, one with each code. Change that latter case to only send one
`SIGIO` signal, using the direction of the current command to determine
the signal code. If the `CMDF_WRITE` flag is set in the current
command, it's in the "write" direction, otherwise it's in the "read"
direction.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_event()` is called from low-level drivers to handle asynchronous
command event flags that are stored in `s->async->events` for subdevice
`s`. It normally clears the event flags as well. As a safety check, it
does nothing if no asynchronous command is running, but it leaves
`s->async->events` unchanged in this case. For additional safety,
change it to always clear the event flags to avoid leaving stale event
flags set when another asynchronous command is set up.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In places where the `s->async` value has been stored in a local
variable, use the variable instead of repeating `s->async`.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Don't use a conditional operator when a simple "not" will do.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_is_subdevice_in_error()` is only used by `comedi_read()` and
`comedi_write()` and is only called (soon) after
`comedi_is_subdevice_running()` returns `false` (with extra conditions
in the case of `comedi_write()`). `comedi_is_subdevice_running()` and
`comedi_get_subdevice_runflags()` both call
`comedi_get_subdevice_runflags()` which uses the subdevice's spin-lock.
Eliminate one use of the subdevice's spin-lock in `comedi_read()` and
`comedi_write()` by calling `comedi_get_subdevice_runflags()` and
checking the runflags directly. Add a couple of inline functions to
check the runflags: `comedi_is_runflags_running()` and
`comedi_is_runflags_in_error()`. These do the same test on runflags as
`comedi_is_subdevice_running()` and `comedi_is_subdevice_in_error()` but
get passed the runflags value directly.
`comedi_is_subdevice_in_error()` is no longer used, so remove it.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
`comedi_set_subdevice_runflags()` changes the comedi subdevice's
`runflags` member according to a bit-mask and new bit values. It's name
might suggest that it only "sets", not "clears". Rename it to
`comedi_update_subdevice_runflags()` to avoid confusion.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reformat remaining block comments to use the usual block comment style.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The unlocked_ioctl handler calls a different function to handle each
supported ioctl command code. Most of these have a block comment
indicating which command code it handles, a brief description, and an
informal description of the inputs and outputs. These block comments
are formatted in various styles. Reformat them to the usual block
comment style and do a bit of rewording for consistency. The comment
block for the `COMEDI_CMD` ioctl is missing, so add one.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the usual block comment style.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ian Abbott
Shraddha Barke
Kirill A. Shutemov
H Hartley Sweeten
Santhosh Pai
Hari Prasath Gujulan Elango
Carlos E. Garcia
Haneen Mohammed