linux/drivers/tty, branch v4.6

devpts: more pty driver interface cleanups

2016-04-26T22:47:32Z

This is more prep-work for the upcoming pty changes. Still just code cleanup with no actual semantic changes. This removes a bunch pointless complexity by just having the slave pty side remember the dentry associated with the devpts slave rather than the inode. That allows us to remove all the "look up the dentry" code for when we want to remove it again. Together with moving the tty pointer from "inode->i_private" to "dentry->d_fsdata" and getting rid of pointless inode locking, this removes about 30 lines of code. Not only is the end result smaller, it's simpler and easier to understand. The old code, for example, depended on the d_find_alias() to not just find the dentry, but also to check that it is still hashed, which in turn validated the tty pointer in the inode. That is a _very_ roundabout way to say "invalidate the cached tty pointer when the dentry is removed". The new code just does dentry->d_fsdata = NULL; in devpts_pty_kill() instead, invalidating the tty pointer rather more directly and obviously. Don't do something complex and subtle when the obvious straightforward approach will do. The rest of the patch (ie apart from code deletion and the above tty pointer clearing) is just switching the calling convention to pass the dentry or file pointer around instead of the inode. Cc: Eric Biederman Cc: Peter Anvin Cc: Andy Lutomirski Cc: Al Viro Cc: Peter Hurley Cc: Serge Hallyn Cc: Willy Tarreau Cc: Aurelien Jarno Cc: Alan Cox Cc: Jann Horn Cc: Greg KH Cc: Jiri Slaby Cc: Florian Weimer Signed-off-by: Linus Torvalds

Merge tag 'tty-4.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2016-04-23T18:13:46Z

Pull serial fixes from Greg KH: "Here are 3 serial driver fixes for issues that have been reported. Two are reverts, fixing problems that were in the big TTY/Serial driver merge in 4.6-rc1, and the last one is a simple bugfix for a regression that showed up in 4.6-rc1 as well. All have been in linux-next with no reported issues" * tag 'tty-4.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: Revert "serial: 8250: Add hardware dependency to RT288X option" tty/serial/8250: fix RS485 half-duplex RX Revert "serial-uartlite: Constify uartlite_be/uartlite_le"

Revert "serial: 8250: Add hardware dependency to RT288X option"

2016-04-19T06:17:37Z

This reverts commit 8d2acdb9fc3a544ab0442634531834d6007b5467. It's causing problems, and somehow I missed that Peter didn't like it at all :( So revert it for now until it gets sorted out. Reported-by: Mason Cc: Peter Hurley Cc: Jean Delvare Cc: Mans Rullgard Cc: Jiri Slaby Cc: John Crispin Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

tty/serial/8250: fix RS485 half-duplex RX

2016-04-19T06:15:38Z

When in half-duplex mode RX will be disabled before TX, but not enabled after deactivating transmitter. This patch enables UART_IER_RLSI and UART_IER_RDI interrupts after TX is over. Cc: Matwey V. Kornilov Signed-off-by: Yegor Yefremov Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250") Acked-by: Matwey V. Kornilov Signed-off-by: Greg Kroah-Hartman

Revert "serial-uartlite: Constify uartlite_be/uartlite_le"

2016-04-19T06:15:38Z

This reverts commit 2905697a82eaf20606ced164d853b52d1b94aaa8. The commit introduced two build warnings: drivers/tty/serial/uartlite.c: In function ‘ulite_request_port’: drivers/tty/serial/uartlite.c:348:21: warning: assignment discards ‘const’ qualifier from pointer target type port->private_data = &uartlite_be; ^ drivers/tty/serial/uartlite.c:354:22: warning: assignment discards ‘const’ qualifier from pointer target type port->private_data = &uartlite_le; ^ Signed-off-by: Sudip Mukherjee Cc: Maarten Brock Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

devpts: clean up interface to pty drivers

2016-04-18T20:43:02Z

This gets rid of the horrible notion of having that struct inode *ptmx_inode be the linchpin of the interface between the pty code and devpts. By de-emphasizing the ptmx inode, a lot of things actually get cleaner, and we will have a much saner way forward. In particular, this will allow us to associate with any particular devpts instance at open-time, and not be artificially tied to one particular ptmx inode. The patch itself is actually fairly straightforward, and apart from some locking and return path cleanups it's pretty mechanical: - the interfaces that devpts exposes all take "struct pts_fs_info *" instead of "struct inode *ptmx_inode" now. NOTE! The "struct pts_fs_info" thing is a completely opaque structure as far as the pty driver is concerned: it's still declared entirely internally to devpts. So the pty code can't actually access it in any way, just pass it as a "cookie" to the devpts code. - the "look up the pts fs info" is now a single clear operation, that also does the reference count increment on the pts superblock. So "devpts_add/del_ref()" is gone, and replaced by a "lookup and get ref" operation (devpts_get_ref(inode)), along with a "put ref" op (devpts_put_ref()). - the pty master "tty->driver_data" field now contains the pts_fs_info, not the ptmx inode. - because we don't care about the ptmx inode any more as some kind of base index, the ref counting can now drop the inode games - it just gets the ref on the superblock. - the pts_fs_info now has a back-pointer to the super_block. That's so that we can easily look up the information we actually need. Although quite often, the pts fs info was actually all we wanted, and not having to look it up based on some magical inode makes things more straightforward. In particular, now that "devpts_get_ref(inode)" operation should really be the *only* place we need to look up what devpts instance we're associated with, and we do it exactly once, at ptmx_open() time. The other side of this is that one ptmx node could now be associated with multiple different devpts instances - you could have a single /dev/ptmx node, and then have multiple mount namespaces with their own instances of devpts mounted on /dev/pts/. And that's all perfectly sane in a model where we just look up the pts instance at open time. This will eventually allow us to get rid of our odd single-vs-multiple pts instance model, but this patch in itself changes no semantics, only an internal binding model. Cc: Eric Biederman Cc: Peter Anvin Cc: Andy Lutomirski Cc: Al Viro Cc: Peter Hurley Cc: Serge Hallyn Cc: Willy Tarreau Cc: Aurelien Jarno Cc: Alan Cox Cc: Jann Horn Cc: Greg KH Cc: Jiri Slaby Cc: Florian Weimer Signed-off-by: Linus Torvalds

tty: Fix merge of "tty: Refactor tty_open()"

2016-04-01T03:49:39Z

Commit e9036d066236 ("tty: Drop krefs for interrupted tty lock") fixed a tty reference counting problem introduced in commit 0bfd464d3fdd ("tty: Wait interruptibly for tty lock on reopen"), so v4.5.0 is correct. However, commit d6203d0c7b73 ("tty: Refactor tty_open()") moved the relevant code for 4.6-rc1; correct the merge. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Fix UML console breakage

2016-04-01T00:14:14Z

User-Mode Linux supplies an alternate TTY_MAJOR driver for stdio console, so the noctty check in tty_open() must apply only to VT driver tty0 devnode and not the UML console driver tty0 devnode. Fixes: 11e1d4aa4da1 ("tty: Consolidate noctty checks in tty_open()") Reported-by: Richard Weinberger Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-linus-4.6-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2016-03-22T19:55:17Z

Pull xen updates from David Vrabel: "Features and fixes for 4.6: - Make earlyprintk=xen work for HVM guests - Remove module support for things never built as modules" * tag 'for-linus-4.6-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: drivers/xen: make platform-pci.c explicitly non-modular drivers/xen: make sys-hypervisor.c explicitly non-modular drivers/xen: make xenbus_dev_[front/back]end explicitly non-modular drivers/xen: make [xen-]ballon explicitly non-modular xen: audit usages of module.h ; remove unnecessary instances xen/x86: Drop mode-selecting ifdefs in startup_xen() xen/x86: Zero out .bss for PV guests hvc_xen: make early_printk work with HVM guests hvc_xen: fix xenboot for DomUs hvc_xen: add earlycon support

serial: 8250: describe CONFIG_SERIAL_8250_RSA

2016-03-08T00:11:14Z

CONFIG_SERIAL_8250_RSA has waited for a long time to have meaningful help text so let's finally describe what this option actually does. Signed-off-by: Maciej S. Szmigiero Signed-off-by: Greg Kroah-Hartman