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path: root/drivers/xen/evtchn.c
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2014-01-06xen/evtchn: support more than 4096 portsDavid Vrabel1-1/+1
Remove the check during unbind for NR_EVENT_CHANNELS as this limits support to less than 4096 ports. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2013-11-06xen: remove deprecated IRQF_DISABLEDMichael Opdenacker1-1/+1
This patch proposes to remove the IRQF_DISABLED flag from drivers/xen code. It's a NOOP since 2.6.35 and it will be removed one day. Note that architecture dependent fixes for IRQF_DISABLED were already submitted through separate patches. Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-08-30xen/evtchn: double free on errorDan Carpenter1-1/+0
The call to del_evtchn() frees "evtchn". Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-08-09xen/evtchn: improve scalability by using per-user locksDavid Vrabel1-80/+112
The global array of port users and the port_user_lock limits scalability of the evtchn device. Instead of the global array lookup, use a per-use (per-fd) tree of event channels bound by that user and protect the tree with a per-user lock. This is also a prerequiste for extended the number of supported event channels, by removing the fixed size, per-event channel array. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-07-30xen/evtchn: avoid a deadlock when unbinding an event channelDavid Vrabel1-19/+2
Unbinding an event channel (either with the ioctl or when the evtchn device is closed) may deadlock because disable_irq() is called with port_user_lock held which is also locked by the interrupt handler. Think of the IOCTL_EVTCHN_UNBIND is being serviced, the routine has just taken the lock, and an interrupt happens. The evtchn_interrupt is invoked, tries to take the lock and spins forever. A quick glance at the code shows that the spinlock is a local IRQ variant. Unfortunately that does not help as "disable_irq() waits for the interrupt handler on all CPUs to stop running. If the irq occurs on another VCPU, it tries to take port_user_lock and can't because the unbind ioctl is holding it." (from David). Hence we cannot depend on the said spinlock to protect us. We could make it a system wide IRQ disable spinlock but there is a better way. We can piggyback on the fact that the existence of the spinlock is to make get_port_user() checks be up-to-date. And we can alter those checks to not depend on the spin lock (as it's protected by u->bind_mutex in the ioctl) and can remove the unnecessary locking (this is IOCTL_EVTCHN_UNBIND) path. In the interrupt handler we cannot use the mutex, but we do not need it. "The unbind disables the irq before making the port user stale, so when you clear it you are guaranteed that the interrupt handler that might use that port cannot be running." (from David). Hence this patch removes the spinlock usage on the teardown path and piggybacks on disable_irq happening before we muck with the get_port_user() data. This ensures that the interrupt handler will never run on stale data. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [v1: Expanded the commit description a bit]
2013-06-28xen: Convert printks to pr_<level>Joe Perches1-2/+4
Convert printks to pr_<level> (excludes printk(KERN_DEBUG...) to be more consistent throughout the xen subsystem. Add pr_fmt with KBUILD_MODNAME or "xen:" KBUILD_MODNAME Coalesce formats and add missing word spaces Add missing newlines Align arguments and reflow to 80 columns Remove DRV_NAME from formats as pr_fmt adds the same content This does change some of the prefixes of these messages but it also does make them more consistent. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-02-19xen: close evtchn port if binding to irq failsWei Liu1-0/+10
CC: stable@vger.kernel.org Signed-off-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-02-19xen-evtchn: correct comment and error outputWei Liu1-2/+2
The evtchn device has been moved to /dev/xen. Also change log level to KERN_ERR as other xen drivers. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-11-21xen/event: Add reference counting to event channelsDaniel De Graaf1-1/+1
Event channels exposed to userspace by the evtchn module may be used by other modules in an asynchronous manner, which requires that reference counting be used to prevent the event channel from being closed before the signals are delivered. The reference count on new event channels defaults to -1 which indicates the event channel is not referenced outside the kernel; evtchn_get fails if called on such an event channel. The event channels made visible to userspace by evtchn have a normal reference count. Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-04-10treewide: remove extra semicolonsJustin P. Mattock1-1/+1
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-11-18Merge branch 'xen/dev-evtchn' into upstream/evtchnJeremy Fitzhardinge1-22/+74
* xen/dev-evtchn: xen/evtchn: add missing static xen/evtchn: Fix name of Xen event-channel device xen/evtchn: don't do unbind_from_irqhandler under spinlock xen/evtchn: remove spurious barrier xen/evtchn: ports start enabled xen/evtchn: dynamically allocate port_user array xen/evtchn: track enabled state for each port
2010-11-18xen/evtchn: the evtchn device is non-seekableJeremy Fitzhardinge1-2/+2
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2010-10-15llseek: automatically add .llseek fopArnd Bergmann1-0/+1
All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-10-05xen/evtchn: add missing staticJeremy Fitzhardinge1-1/+1
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2010-05-28xen/evtchn: Fix name of Xen event-channel deviceBastian Blank1-1/+1
The Xen event-channel device is named evtchn in the kernel but always used as /dev/xen/evtchn in userspace. This patch fixes the name. Signed-off-by: Bastian Blank <waldi@debian.org> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2010-05-28xen/evtchn: don't do unbind_from_irqhandler under spinlockJeremy Fitzhardinge1-2/+11
unbind_from_irqhandler can end up doing /proc operations, which can't happen under a spinlock. So before removing the IRQ handler, disable the irq under the port_user lock (masking the underlying event channel and making sure the irq handler isn't running concurrently and won't start running), then remove the handler without the lock. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo1-1/+0
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2009-11-04xen: move Xen-testing predicates to common headerJeremy Fitzhardinge1-0/+2
Move xen_domain and related tests out of asm-x86 to xen/xen.h so they can be included whenever they are necessary. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-20includecheck fix: drivers/xen, evtchn.cJaswinder Singh Rajput1-1/+0
fix the following 'make includecheck' warning: drivers/xen/evtchn.c: linux/errno.h is included more than once. Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Cc: chrisw@sous-sol.org Cc: Sam Ravnborg <sam@ravnborg.org> LKML-Reference: <1247067749.4382.90.camel@ht.satnam> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-09-18xen/evtchn: remove spurious barrierJeremy Fitzhardinge1-3/+0
evtchn_unbind_from_user() is called under a lock, so there's no need to worry about the ordering of unbind_from_irqhandler vs clearing the port per-user data. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-09-18xen/evtchn: ports start enabledJeremy Fitzhardinge1-5/+4
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-09-18xen/evtchn: dynamically allocate port_user arrayJeremy Fitzhardinge1-2/+8
We only need the array when running as a Xen domain, so dynamically allocate it as needed to save on bss space. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-09-18xen/evtchn: track enabled state for each portJeremy Fitzhardinge1-15/+56
enable/disable_irq() complain if the enables/disables are unbalanced, so keep track of the state and avoid redundant enables. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-03-30xen/dev-evtchn: clean up locking in evtchnJeremy Fitzhardinge1-12/+25
Define a new per_user_data mutex to serialize bind/unbind operations to prevent them from racing with each other. Fix error returns and don't do a bind while holding a spinlock. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-03-30xen: add /dev/xen/evtchn driverIan Campbell1-0/+494
This driver is used by application which wish to receive notifications from the hypervisor or other guests via Xen's event channel mechanism. In particular it is used by the xenstore daemon in domain 0. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>