forked from Minki/linux
a99bbaf5ee
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
984 lines
24 KiB
C
984 lines
24 KiB
C
/*
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* This file contains the procedures for the handling of select and poll
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*
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* Created for Linux based loosely upon Mathius Lattner's minix
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* patches by Peter MacDonald. Heavily edited by Linus.
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*
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* 4 February 1994
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* COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
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* flag set in its personality we do *not* modify the given timeout
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* parameter to reflect time remaining.
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*
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* 24 January 2000
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* Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation
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* of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/syscalls.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/poll.h>
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#include <linux/personality.h> /* for STICKY_TIMEOUTS */
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#include <linux/file.h>
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#include <linux/fdtable.h>
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#include <linux/fs.h>
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#include <linux/rcupdate.h>
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#include <linux/hrtimer.h>
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#include <asm/uaccess.h>
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/*
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* Estimate expected accuracy in ns from a timeval.
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*
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* After quite a bit of churning around, we've settled on
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* a simple thing of taking 0.1% of the timeout as the
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* slack, with a cap of 100 msec.
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* "nice" tasks get a 0.5% slack instead.
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*
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* Consider this comment an open invitation to come up with even
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* better solutions..
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*/
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#define MAX_SLACK (100 * NSEC_PER_MSEC)
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static long __estimate_accuracy(struct timespec *tv)
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{
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long slack;
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int divfactor = 1000;
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if (tv->tv_sec < 0)
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return 0;
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if (task_nice(current) > 0)
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divfactor = divfactor / 5;
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if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor))
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return MAX_SLACK;
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slack = tv->tv_nsec / divfactor;
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slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
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if (slack > MAX_SLACK)
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return MAX_SLACK;
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return slack;
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}
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static long estimate_accuracy(struct timespec *tv)
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{
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unsigned long ret;
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struct timespec now;
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/*
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* Realtime tasks get a slack of 0 for obvious reasons.
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*/
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if (rt_task(current))
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return 0;
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ktime_get_ts(&now);
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now = timespec_sub(*tv, now);
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ret = __estimate_accuracy(&now);
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if (ret < current->timer_slack_ns)
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return current->timer_slack_ns;
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return ret;
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}
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struct poll_table_page {
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struct poll_table_page * next;
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struct poll_table_entry * entry;
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struct poll_table_entry entries[0];
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};
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#define POLL_TABLE_FULL(table) \
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((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
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/*
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* Ok, Peter made a complicated, but straightforward multiple_wait() function.
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* I have rewritten this, taking some shortcuts: This code may not be easy to
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* follow, but it should be free of race-conditions, and it's practical. If you
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* understand what I'm doing here, then you understand how the linux
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* sleep/wakeup mechanism works.
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*
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* Two very simple procedures, poll_wait() and poll_freewait() make all the
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* work. poll_wait() is an inline-function defined in <linux/poll.h>,
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* as all select/poll functions have to call it to add an entry to the
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* poll table.
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*/
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static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
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poll_table *p);
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void poll_initwait(struct poll_wqueues *pwq)
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{
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init_poll_funcptr(&pwq->pt, __pollwait);
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pwq->polling_task = current;
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pwq->triggered = 0;
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pwq->error = 0;
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pwq->table = NULL;
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pwq->inline_index = 0;
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}
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EXPORT_SYMBOL(poll_initwait);
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static void free_poll_entry(struct poll_table_entry *entry)
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{
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remove_wait_queue(entry->wait_address, &entry->wait);
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fput(entry->filp);
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}
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void poll_freewait(struct poll_wqueues *pwq)
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{
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struct poll_table_page * p = pwq->table;
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int i;
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for (i = 0; i < pwq->inline_index; i++)
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free_poll_entry(pwq->inline_entries + i);
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while (p) {
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struct poll_table_entry * entry;
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struct poll_table_page *old;
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entry = p->entry;
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do {
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entry--;
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free_poll_entry(entry);
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} while (entry > p->entries);
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old = p;
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p = p->next;
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free_page((unsigned long) old);
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}
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}
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EXPORT_SYMBOL(poll_freewait);
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static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
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{
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struct poll_table_page *table = p->table;
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if (p->inline_index < N_INLINE_POLL_ENTRIES)
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return p->inline_entries + p->inline_index++;
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if (!table || POLL_TABLE_FULL(table)) {
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struct poll_table_page *new_table;
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new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
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if (!new_table) {
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p->error = -ENOMEM;
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return NULL;
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}
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new_table->entry = new_table->entries;
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new_table->next = table;
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p->table = new_table;
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table = new_table;
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}
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return table->entry++;
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}
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static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
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{
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struct poll_wqueues *pwq = wait->private;
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DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
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/*
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* Although this function is called under waitqueue lock, LOCK
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* doesn't imply write barrier and the users expect write
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* barrier semantics on wakeup functions. The following
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* smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
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* and is paired with set_mb() in poll_schedule_timeout.
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*/
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smp_wmb();
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pwq->triggered = 1;
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/*
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* Perform the default wake up operation using a dummy
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* waitqueue.
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*
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* TODO: This is hacky but there currently is no interface to
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* pass in @sync. @sync is scheduled to be removed and once
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* that happens, wake_up_process() can be used directly.
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*/
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return default_wake_function(&dummy_wait, mode, sync, key);
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}
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static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
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{
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struct poll_table_entry *entry;
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entry = container_of(wait, struct poll_table_entry, wait);
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if (key && !((unsigned long)key & entry->key))
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return 0;
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return __pollwake(wait, mode, sync, key);
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}
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/* Add a new entry */
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static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
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poll_table *p)
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{
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struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
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struct poll_table_entry *entry = poll_get_entry(pwq);
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if (!entry)
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return;
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get_file(filp);
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entry->filp = filp;
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entry->wait_address = wait_address;
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entry->key = p->key;
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init_waitqueue_func_entry(&entry->wait, pollwake);
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entry->wait.private = pwq;
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add_wait_queue(wait_address, &entry->wait);
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}
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int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
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ktime_t *expires, unsigned long slack)
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{
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int rc = -EINTR;
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set_current_state(state);
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if (!pwq->triggered)
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rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
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__set_current_state(TASK_RUNNING);
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/*
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* Prepare for the next iteration.
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*
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* The following set_mb() serves two purposes. First, it's
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* the counterpart rmb of the wmb in pollwake() such that data
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* written before wake up is always visible after wake up.
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* Second, the full barrier guarantees that triggered clearing
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* doesn't pass event check of the next iteration. Note that
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* this problem doesn't exist for the first iteration as
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* add_wait_queue() has full barrier semantics.
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*/
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set_mb(pwq->triggered, 0);
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return rc;
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}
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EXPORT_SYMBOL(poll_schedule_timeout);
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/**
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* poll_select_set_timeout - helper function to setup the timeout value
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* @to: pointer to timespec variable for the final timeout
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* @sec: seconds (from user space)
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* @nsec: nanoseconds (from user space)
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*
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* Note, we do not use a timespec for the user space value here, That
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* way we can use the function for timeval and compat interfaces as well.
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*
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* Returns -EINVAL if sec/nsec are not normalized. Otherwise 0.
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*/
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int poll_select_set_timeout(struct timespec *to, long sec, long nsec)
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{
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struct timespec ts = {.tv_sec = sec, .tv_nsec = nsec};
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if (!timespec_valid(&ts))
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return -EINVAL;
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/* Optimize for the zero timeout value here */
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if (!sec && !nsec) {
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to->tv_sec = to->tv_nsec = 0;
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} else {
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ktime_get_ts(to);
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*to = timespec_add_safe(*to, ts);
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}
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return 0;
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}
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static int poll_select_copy_remaining(struct timespec *end_time, void __user *p,
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int timeval, int ret)
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{
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struct timespec rts;
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struct timeval rtv;
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if (!p)
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return ret;
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if (current->personality & STICKY_TIMEOUTS)
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goto sticky;
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/* No update for zero timeout */
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if (!end_time->tv_sec && !end_time->tv_nsec)
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return ret;
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ktime_get_ts(&rts);
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rts = timespec_sub(*end_time, rts);
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if (rts.tv_sec < 0)
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rts.tv_sec = rts.tv_nsec = 0;
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if (timeval) {
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rtv.tv_sec = rts.tv_sec;
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rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
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if (!copy_to_user(p, &rtv, sizeof(rtv)))
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return ret;
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} else if (!copy_to_user(p, &rts, sizeof(rts)))
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return ret;
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/*
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* If an application puts its timeval in read-only memory, we
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* don't want the Linux-specific update to the timeval to
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* cause a fault after the select has completed
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* successfully. However, because we're not updating the
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* timeval, we can't restart the system call.
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*/
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sticky:
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if (ret == -ERESTARTNOHAND)
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ret = -EINTR;
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return ret;
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}
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#define FDS_IN(fds, n) (fds->in + n)
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#define FDS_OUT(fds, n) (fds->out + n)
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#define FDS_EX(fds, n) (fds->ex + n)
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#define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
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static int max_select_fd(unsigned long n, fd_set_bits *fds)
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{
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unsigned long *open_fds;
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unsigned long set;
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int max;
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struct fdtable *fdt;
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/* handle last in-complete long-word first */
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set = ~(~0UL << (n & (__NFDBITS-1)));
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n /= __NFDBITS;
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fdt = files_fdtable(current->files);
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open_fds = fdt->open_fds->fds_bits+n;
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max = 0;
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if (set) {
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set &= BITS(fds, n);
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if (set) {
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if (!(set & ~*open_fds))
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goto get_max;
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return -EBADF;
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}
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}
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while (n) {
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open_fds--;
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n--;
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set = BITS(fds, n);
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if (!set)
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continue;
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if (set & ~*open_fds)
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return -EBADF;
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if (max)
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continue;
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get_max:
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do {
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max++;
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set >>= 1;
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} while (set);
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max += n * __NFDBITS;
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}
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return max;
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}
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#define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
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#define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
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#define POLLEX_SET (POLLPRI)
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static inline void wait_key_set(poll_table *wait, unsigned long in,
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unsigned long out, unsigned long bit)
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{
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if (wait) {
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wait->key = POLLEX_SET;
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if (in & bit)
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wait->key |= POLLIN_SET;
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if (out & bit)
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wait->key |= POLLOUT_SET;
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}
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}
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int do_select(int n, fd_set_bits *fds, struct timespec *end_time)
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{
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ktime_t expire, *to = NULL;
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struct poll_wqueues table;
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poll_table *wait;
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int retval, i, timed_out = 0;
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unsigned long slack = 0;
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rcu_read_lock();
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retval = max_select_fd(n, fds);
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rcu_read_unlock();
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if (retval < 0)
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return retval;
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n = retval;
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poll_initwait(&table);
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wait = &table.pt;
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if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
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wait = NULL;
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timed_out = 1;
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}
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if (end_time && !timed_out)
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slack = estimate_accuracy(end_time);
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retval = 0;
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for (;;) {
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unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
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inp = fds->in; outp = fds->out; exp = fds->ex;
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rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
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for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
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unsigned long in, out, ex, all_bits, bit = 1, mask, j;
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unsigned long res_in = 0, res_out = 0, res_ex = 0;
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const struct file_operations *f_op = NULL;
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struct file *file = NULL;
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in = *inp++; out = *outp++; ex = *exp++;
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all_bits = in | out | ex;
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if (all_bits == 0) {
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i += __NFDBITS;
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continue;
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}
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for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
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int fput_needed;
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if (i >= n)
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break;
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if (!(bit & all_bits))
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continue;
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file = fget_light(i, &fput_needed);
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if (file) {
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f_op = file->f_op;
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mask = DEFAULT_POLLMASK;
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if (f_op && f_op->poll) {
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wait_key_set(wait, in, out, bit);
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mask = (*f_op->poll)(file, wait);
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}
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fput_light(file, fput_needed);
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if ((mask & POLLIN_SET) && (in & bit)) {
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res_in |= bit;
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retval++;
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wait = NULL;
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}
|
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if ((mask & POLLOUT_SET) && (out & bit)) {
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res_out |= bit;
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retval++;
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wait = NULL;
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}
|
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if ((mask & POLLEX_SET) && (ex & bit)) {
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res_ex |= bit;
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retval++;
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wait = NULL;
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}
|
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}
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}
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if (res_in)
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*rinp = res_in;
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if (res_out)
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*routp = res_out;
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if (res_ex)
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*rexp = res_ex;
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cond_resched();
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}
|
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wait = NULL;
|
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if (retval || timed_out || signal_pending(current))
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break;
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if (table.error) {
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retval = table.error;
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break;
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}
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|
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/*
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* If this is the first loop and we have a timeout
|
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* given, then we convert to ktime_t and set the to
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* pointer to the expiry value.
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*/
|
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if (end_time && !to) {
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expire = timespec_to_ktime(*end_time);
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to = &expire;
|
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}
|
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|
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if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
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to, slack))
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timed_out = 1;
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}
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|
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poll_freewait(&table);
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|
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return retval;
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}
|
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|
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/*
|
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* We can actually return ERESTARTSYS instead of EINTR, but I'd
|
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* like to be certain this leads to no problems. So I return
|
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* EINTR just for safety.
|
|
*
|
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* Update: ERESTARTSYS breaks at least the xview clock binary, so
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* I'm trying ERESTARTNOHAND which restart only when you want to.
|
|
*/
|
|
#define MAX_SELECT_SECONDS \
|
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((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)
|
|
|
|
int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
|
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fd_set __user *exp, struct timespec *end_time)
|
|
{
|
|
fd_set_bits fds;
|
|
void *bits;
|
|
int ret, max_fds;
|
|
unsigned int size;
|
|
struct fdtable *fdt;
|
|
/* Allocate small arguments on the stack to save memory and be faster */
|
|
long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
|
|
|
|
ret = -EINVAL;
|
|
if (n < 0)
|
|
goto out_nofds;
|
|
|
|
/* max_fds can increase, so grab it once to avoid race */
|
|
rcu_read_lock();
|
|
fdt = files_fdtable(current->files);
|
|
max_fds = fdt->max_fds;
|
|
rcu_read_unlock();
|
|
if (n > max_fds)
|
|
n = max_fds;
|
|
|
|
/*
|
|
* We need 6 bitmaps (in/out/ex for both incoming and outgoing),
|
|
* since we used fdset we need to allocate memory in units of
|
|
* long-words.
|
|
*/
|
|
size = FDS_BYTES(n);
|
|
bits = stack_fds;
|
|
if (size > sizeof(stack_fds) / 6) {
|
|
/* Not enough space in on-stack array; must use kmalloc */
|
|
ret = -ENOMEM;
|
|
bits = kmalloc(6 * size, GFP_KERNEL);
|
|
if (!bits)
|
|
goto out_nofds;
|
|
}
|
|
fds.in = bits;
|
|
fds.out = bits + size;
|
|
fds.ex = bits + 2*size;
|
|
fds.res_in = bits + 3*size;
|
|
fds.res_out = bits + 4*size;
|
|
fds.res_ex = bits + 5*size;
|
|
|
|
if ((ret = get_fd_set(n, inp, fds.in)) ||
|
|
(ret = get_fd_set(n, outp, fds.out)) ||
|
|
(ret = get_fd_set(n, exp, fds.ex)))
|
|
goto out;
|
|
zero_fd_set(n, fds.res_in);
|
|
zero_fd_set(n, fds.res_out);
|
|
zero_fd_set(n, fds.res_ex);
|
|
|
|
ret = do_select(n, &fds, end_time);
|
|
|
|
if (ret < 0)
|
|
goto out;
|
|
if (!ret) {
|
|
ret = -ERESTARTNOHAND;
|
|
if (signal_pending(current))
|
|
goto out;
|
|
ret = 0;
|
|
}
|
|
|
|
if (set_fd_set(n, inp, fds.res_in) ||
|
|
set_fd_set(n, outp, fds.res_out) ||
|
|
set_fd_set(n, exp, fds.res_ex))
|
|
ret = -EFAULT;
|
|
|
|
out:
|
|
if (bits != stack_fds)
|
|
kfree(bits);
|
|
out_nofds:
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
|
|
fd_set __user *, exp, struct timeval __user *, tvp)
|
|
{
|
|
struct timespec end_time, *to = NULL;
|
|
struct timeval tv;
|
|
int ret;
|
|
|
|
if (tvp) {
|
|
if (copy_from_user(&tv, tvp, sizeof(tv)))
|
|
return -EFAULT;
|
|
|
|
to = &end_time;
|
|
if (poll_select_set_timeout(to,
|
|
tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
|
|
(tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
|
|
return -EINVAL;
|
|
}
|
|
|
|
ret = core_sys_select(n, inp, outp, exp, to);
|
|
ret = poll_select_copy_remaining(&end_time, tvp, 1, ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
#ifdef HAVE_SET_RESTORE_SIGMASK
|
|
static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
|
|
fd_set __user *exp, struct timespec __user *tsp,
|
|
const sigset_t __user *sigmask, size_t sigsetsize)
|
|
{
|
|
sigset_t ksigmask, sigsaved;
|
|
struct timespec ts, end_time, *to = NULL;
|
|
int ret;
|
|
|
|
if (tsp) {
|
|
if (copy_from_user(&ts, tsp, sizeof(ts)))
|
|
return -EFAULT;
|
|
|
|
to = &end_time;
|
|
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (sigmask) {
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */
|
|
if (sigsetsize != sizeof(sigset_t))
|
|
return -EINVAL;
|
|
if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
|
|
return -EFAULT;
|
|
|
|
sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
|
sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
|
|
}
|
|
|
|
ret = core_sys_select(n, inp, outp, exp, to);
|
|
ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
|
|
|
|
if (ret == -ERESTARTNOHAND) {
|
|
/*
|
|
* Don't restore the signal mask yet. Let do_signal() deliver
|
|
* the signal on the way back to userspace, before the signal
|
|
* mask is restored.
|
|
*/
|
|
if (sigmask) {
|
|
memcpy(¤t->saved_sigmask, &sigsaved,
|
|
sizeof(sigsaved));
|
|
set_restore_sigmask();
|
|
}
|
|
} else if (sigmask)
|
|
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Most architectures can't handle 7-argument syscalls. So we provide a
|
|
* 6-argument version where the sixth argument is a pointer to a structure
|
|
* which has a pointer to the sigset_t itself followed by a size_t containing
|
|
* the sigset size.
|
|
*/
|
|
SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
|
|
fd_set __user *, exp, struct timespec __user *, tsp,
|
|
void __user *, sig)
|
|
{
|
|
size_t sigsetsize = 0;
|
|
sigset_t __user *up = NULL;
|
|
|
|
if (sig) {
|
|
if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
|
|
|| __get_user(up, (sigset_t __user * __user *)sig)
|
|
|| __get_user(sigsetsize,
|
|
(size_t __user *)(sig+sizeof(void *))))
|
|
return -EFAULT;
|
|
}
|
|
|
|
return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize);
|
|
}
|
|
#endif /* HAVE_SET_RESTORE_SIGMASK */
|
|
|
|
struct poll_list {
|
|
struct poll_list *next;
|
|
int len;
|
|
struct pollfd entries[0];
|
|
};
|
|
|
|
#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
|
|
|
|
/*
|
|
* Fish for pollable events on the pollfd->fd file descriptor. We're only
|
|
* interested in events matching the pollfd->events mask, and the result
|
|
* matching that mask is both recorded in pollfd->revents and returned. The
|
|
* pwait poll_table will be used by the fd-provided poll handler for waiting,
|
|
* if non-NULL.
|
|
*/
|
|
static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
|
|
{
|
|
unsigned int mask;
|
|
int fd;
|
|
|
|
mask = 0;
|
|
fd = pollfd->fd;
|
|
if (fd >= 0) {
|
|
int fput_needed;
|
|
struct file * file;
|
|
|
|
file = fget_light(fd, &fput_needed);
|
|
mask = POLLNVAL;
|
|
if (file != NULL) {
|
|
mask = DEFAULT_POLLMASK;
|
|
if (file->f_op && file->f_op->poll) {
|
|
if (pwait)
|
|
pwait->key = pollfd->events |
|
|
POLLERR | POLLHUP;
|
|
mask = file->f_op->poll(file, pwait);
|
|
}
|
|
/* Mask out unneeded events. */
|
|
mask &= pollfd->events | POLLERR | POLLHUP;
|
|
fput_light(file, fput_needed);
|
|
}
|
|
}
|
|
pollfd->revents = mask;
|
|
|
|
return mask;
|
|
}
|
|
|
|
static int do_poll(unsigned int nfds, struct poll_list *list,
|
|
struct poll_wqueues *wait, struct timespec *end_time)
|
|
{
|
|
poll_table* pt = &wait->pt;
|
|
ktime_t expire, *to = NULL;
|
|
int timed_out = 0, count = 0;
|
|
unsigned long slack = 0;
|
|
|
|
/* Optimise the no-wait case */
|
|
if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
|
|
pt = NULL;
|
|
timed_out = 1;
|
|
}
|
|
|
|
if (end_time && !timed_out)
|
|
slack = estimate_accuracy(end_time);
|
|
|
|
for (;;) {
|
|
struct poll_list *walk;
|
|
|
|
for (walk = list; walk != NULL; walk = walk->next) {
|
|
struct pollfd * pfd, * pfd_end;
|
|
|
|
pfd = walk->entries;
|
|
pfd_end = pfd + walk->len;
|
|
for (; pfd != pfd_end; pfd++) {
|
|
/*
|
|
* Fish for events. If we found one, record it
|
|
* and kill the poll_table, so we don't
|
|
* needlessly register any other waiters after
|
|
* this. They'll get immediately deregistered
|
|
* when we break out and return.
|
|
*/
|
|
if (do_pollfd(pfd, pt)) {
|
|
count++;
|
|
pt = NULL;
|
|
}
|
|
}
|
|
}
|
|
/*
|
|
* All waiters have already been registered, so don't provide
|
|
* a poll_table to them on the next loop iteration.
|
|
*/
|
|
pt = NULL;
|
|
if (!count) {
|
|
count = wait->error;
|
|
if (signal_pending(current))
|
|
count = -EINTR;
|
|
}
|
|
if (count || timed_out)
|
|
break;
|
|
|
|
/*
|
|
* If this is the first loop and we have a timeout
|
|
* given, then we convert to ktime_t and set the to
|
|
* pointer to the expiry value.
|
|
*/
|
|
if (end_time && !to) {
|
|
expire = timespec_to_ktime(*end_time);
|
|
to = &expire;
|
|
}
|
|
|
|
if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
|
|
timed_out = 1;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
|
|
sizeof(struct pollfd))
|
|
|
|
int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
|
|
struct timespec *end_time)
|
|
{
|
|
struct poll_wqueues table;
|
|
int err = -EFAULT, fdcount, len, size;
|
|
/* Allocate small arguments on the stack to save memory and be
|
|
faster - use long to make sure the buffer is aligned properly
|
|
on 64 bit archs to avoid unaligned access */
|
|
long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
|
|
struct poll_list *const head = (struct poll_list *)stack_pps;
|
|
struct poll_list *walk = head;
|
|
unsigned long todo = nfds;
|
|
|
|
if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
|
|
return -EINVAL;
|
|
|
|
len = min_t(unsigned int, nfds, N_STACK_PPS);
|
|
for (;;) {
|
|
walk->next = NULL;
|
|
walk->len = len;
|
|
if (!len)
|
|
break;
|
|
|
|
if (copy_from_user(walk->entries, ufds + nfds-todo,
|
|
sizeof(struct pollfd) * walk->len))
|
|
goto out_fds;
|
|
|
|
todo -= walk->len;
|
|
if (!todo)
|
|
break;
|
|
|
|
len = min(todo, POLLFD_PER_PAGE);
|
|
size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
|
|
walk = walk->next = kmalloc(size, GFP_KERNEL);
|
|
if (!walk) {
|
|
err = -ENOMEM;
|
|
goto out_fds;
|
|
}
|
|
}
|
|
|
|
poll_initwait(&table);
|
|
fdcount = do_poll(nfds, head, &table, end_time);
|
|
poll_freewait(&table);
|
|
|
|
for (walk = head; walk; walk = walk->next) {
|
|
struct pollfd *fds = walk->entries;
|
|
int j;
|
|
|
|
for (j = 0; j < walk->len; j++, ufds++)
|
|
if (__put_user(fds[j].revents, &ufds->revents))
|
|
goto out_fds;
|
|
}
|
|
|
|
err = fdcount;
|
|
out_fds:
|
|
walk = head->next;
|
|
while (walk) {
|
|
struct poll_list *pos = walk;
|
|
walk = walk->next;
|
|
kfree(pos);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static long do_restart_poll(struct restart_block *restart_block)
|
|
{
|
|
struct pollfd __user *ufds = restart_block->poll.ufds;
|
|
int nfds = restart_block->poll.nfds;
|
|
struct timespec *to = NULL, end_time;
|
|
int ret;
|
|
|
|
if (restart_block->poll.has_timeout) {
|
|
end_time.tv_sec = restart_block->poll.tv_sec;
|
|
end_time.tv_nsec = restart_block->poll.tv_nsec;
|
|
to = &end_time;
|
|
}
|
|
|
|
ret = do_sys_poll(ufds, nfds, to);
|
|
|
|
if (ret == -EINTR) {
|
|
restart_block->fn = do_restart_poll;
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
|
|
long, timeout_msecs)
|
|
{
|
|
struct timespec end_time, *to = NULL;
|
|
int ret;
|
|
|
|
if (timeout_msecs >= 0) {
|
|
to = &end_time;
|
|
poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
|
|
NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
|
|
}
|
|
|
|
ret = do_sys_poll(ufds, nfds, to);
|
|
|
|
if (ret == -EINTR) {
|
|
struct restart_block *restart_block;
|
|
|
|
restart_block = ¤t_thread_info()->restart_block;
|
|
restart_block->fn = do_restart_poll;
|
|
restart_block->poll.ufds = ufds;
|
|
restart_block->poll.nfds = nfds;
|
|
|
|
if (timeout_msecs >= 0) {
|
|
restart_block->poll.tv_sec = end_time.tv_sec;
|
|
restart_block->poll.tv_nsec = end_time.tv_nsec;
|
|
restart_block->poll.has_timeout = 1;
|
|
} else
|
|
restart_block->poll.has_timeout = 0;
|
|
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
#ifdef HAVE_SET_RESTORE_SIGMASK
|
|
SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
|
|
struct timespec __user *, tsp, const sigset_t __user *, sigmask,
|
|
size_t, sigsetsize)
|
|
{
|
|
sigset_t ksigmask, sigsaved;
|
|
struct timespec ts, end_time, *to = NULL;
|
|
int ret;
|
|
|
|
if (tsp) {
|
|
if (copy_from_user(&ts, tsp, sizeof(ts)))
|
|
return -EFAULT;
|
|
|
|
to = &end_time;
|
|
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (sigmask) {
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */
|
|
if (sigsetsize != sizeof(sigset_t))
|
|
return -EINVAL;
|
|
if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
|
|
return -EFAULT;
|
|
|
|
sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
|
sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
|
|
}
|
|
|
|
ret = do_sys_poll(ufds, nfds, to);
|
|
|
|
/* We can restart this syscall, usually */
|
|
if (ret == -EINTR) {
|
|
/*
|
|
* Don't restore the signal mask yet. Let do_signal() deliver
|
|
* the signal on the way back to userspace, before the signal
|
|
* mask is restored.
|
|
*/
|
|
if (sigmask) {
|
|
memcpy(¤t->saved_sigmask, &sigsaved,
|
|
sizeof(sigsaved));
|
|
set_restore_sigmask();
|
|
}
|
|
ret = -ERESTARTNOHAND;
|
|
} else if (sigmask)
|
|
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
|
|
|
|
ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
|
|
|
|
return ret;
|
|
}
|
|
#endif /* HAVE_SET_RESTORE_SIGMASK */
|