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Date: Tue, 22 Jan 2013 14:15:40 +0400
From: Andrey Vagin <avagin@...nvz.org>
To: linux-kernel@...r.kernel.org
Cc: criu@...nvz.org, linux-fsdevel@...r.kernel.org,
linux-api@...r.kernel.org, Andrey Vagin <avagin@...nvz.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
David Howells <dhowells@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Oleg Nesterov <oleg@...hat.com>,
Michael Kerrisk <mtk.manpages@...il.com>,
Pavel Emelyanov <xemul@...allels.com>,
Cyrill Gorcunov <gorcunov@...nvz.org>
Subject: [PATCH 2/3] signalfd: add ability to choose a private or shared queue
This patch is added two flags SFD_SHARED_QUEUE and SFD_PER_THREAD_QUEUE
SFD_SHARED_QUEUE - read signals from a shared (process wide) queue
SFD_PER_THREAD_QUEUE - read signals from a per-thread queue
Without these flags or with both flags signals are read from both queues.
This functionality is required for dumping pending signals.
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Cc: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc: David Howells <dhowells@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Michael Kerrisk <mtk.manpages@...il.com>
Cc: Pavel Emelyanov <xemul@...allels.com>
CC: Cyrill Gorcunov <gorcunov@...nvz.org>
Signed-off-by: Andrey Vagin <avagin@...nvz.org>
---
fs/signalfd.c | 30 ++++++++++++++++++++++--------
include/uapi/linux/signalfd.h | 4 ++++
2 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/fs/signalfd.c b/fs/signalfd.c
index c723b5d..8019ec9 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -61,13 +61,17 @@ static unsigned int signalfd_poll(struct file *file, poll_table *wait)
{
struct signalfd_ctx *ctx = file->private_data;
unsigned int events = 0;
+ unsigned int flags = file->f_flags;
poll_wait(file, ¤t->sighand->signalfd_wqh, wait);
spin_lock_irq(¤t->sighand->siglock);
- if (next_signal(¤t->pending, &ctx->sigmask) ||
- next_signal(¤t->signal->shared_pending,
- &ctx->sigmask))
+ if ((flags & SFD_PER_THREAD_QUEUE) &&
+ next_signal(¤t->pending, &ctx->sigmask))
+ events |= POLLIN;
+
+ if ((flags & SFD_SHARED_QUEUE) &&
+ next_signal(¤t->signal->shared_pending, &ctx->sigmask))
events |= POLLIN;
spin_unlock_irq(¤t->sighand->siglock);
@@ -189,13 +193,13 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
}
static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info,
- int nonblock)
+ int nonblock, int qmask)
{
ssize_t ret;
DECLARE_WAITQUEUE(wait, current);
spin_lock_irq(¤t->sighand->siglock);
- ret = dequeue_signal(current, &ctx->sigmask, info);
+ ret = do_dequeue_signal(current, &ctx->sigmask, info, qmask);
switch (ret) {
case 0:
if (!nonblock)
@@ -209,7 +213,7 @@ static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info,
add_wait_queue(¤t->sighand->signalfd_wqh, &wait);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
- ret = dequeue_signal(current, &ctx->sigmask, info);
+ ret = do_dequeue_signal(current, &ctx->sigmask, info, qmask);
if (ret != 0)
break;
if (signal_pending(current)) {
@@ -240,16 +244,23 @@ static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,
struct signalfd_siginfo __user *siginfo;
int nonblock = file->f_flags & O_NONBLOCK;
bool raw = file->f_flags & SFD_RAW;
+ int qmask = 0;
ssize_t ret, total = 0;
siginfo_t info;
+ if (file->f_flags & SFD_PER_THREAD_QUEUE)
+ qmask |= SIGQUEUE_PRIVATE;
+ if (file->f_flags & SFD_SHARED_QUEUE)
+ qmask |= SIGQUEUE_SHARED;
+
count /= sizeof(struct signalfd_siginfo);
if (!count)
return -EINVAL;
siginfo = (struct signalfd_siginfo __user *) buf;
do {
- ret = signalfd_dequeue(ctx, &info, nonblock);
+ ret = signalfd_dequeue(ctx, &info, nonblock, qmask);
+
if (unlikely(ret <= 0))
break;
@@ -292,6 +303,8 @@ static const struct file_operations signalfd_fops = {
.llseek = noop_llseek,
};
+#define SFD_QUEUES (SFD_SHARED_QUEUE | SFD_PER_THREAD_QUEUE)
+
SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
size_t, sizemask, int, flags)
{
@@ -302,7 +315,7 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);
- if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK | SFD_RAW))
+ if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK | SFD_RAW | SFD_QUEUES))
return -EINVAL;
if (sizemask != sizeof(sigset_t) ||
@@ -338,6 +351,7 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
goto out;
}
+ file->f_flags |= (flags & SFD_QUEUES) ? : SFD_QUEUES;
file->f_flags |= flags & SFD_RAW;
fd_install(ufd, file);
diff --git a/include/uapi/linux/signalfd.h b/include/uapi/linux/signalfd.h
index bc31849..481b658 100644
--- a/include/uapi/linux/signalfd.h
+++ b/include/uapi/linux/signalfd.h
@@ -16,6 +16,10 @@
#define SFD_CLOEXEC O_CLOEXEC
#define SFD_NONBLOCK O_NONBLOCK
#define SFD_RAW O_DIRECT
+/* Read signals from a shared (process wide) queue */
+#define SFD_SHARED_QUEUE O_DIRECTORY
+/* Read signals from a per-thread queue */
+#define SFD_PER_THREAD_QUEUE O_EXCL
struct signalfd_siginfo {
__u32 ssi_signo;
--
1.7.11.7
--
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