From 8cd75c4d6b229bb4e3de9264466731e3a32e0133 Mon Sep 17 00:00:00 2001 From: Richard Braun Date: Tue, 26 Feb 2013 22:24:47 +0100 Subject: Add io_select_timeout to the io interface This change fixes a problem that can occur with non-blocking (and also blocking for very short times) select/poll calls. The problem occurs because the timeout is implemented at the client side. For a non-blocking call, this means that (depending on the code path taken in the C library) the client could get a timeout without a full RPC round-trip to the server. Moving the implementation of the timeout to the servers guarantees a full round-trip, and correct results for non-blocking calls. The modifications in this change depend on the availability of the recently added pthread_hurd_cond_timedwait_np function in libpthread. * boot/boot.c (io_select_common): New static function. (S_io_select): Use io_select_common. (S_io_select_timeout): New function which makes use of io_select_common. * console-client/kbd-repeat.c (repeater_select): Add a timeout parameter. * console-client/pc-mouse.c (repeater_select): Likewise. * console-client/trans.c (io_select_common): New static function. (netfs_S_io_select): Use io_select_common. (netfs_S_io_select_timeout): New function which makes use of io_select_common. * console-client/trans.h (struct consnode): Add a timeout parameter. * hurd/io.defs (io_select_timeout): New MIG routine. * hurd/io_reply.defs (io_select_timeout_reply): New MIG simpleroutine. * hurd/io_request.defs (io_select_timeout_request): Likewise. * libdiskfs/io-select.c (diskfs_S_io_select_timeout): New function. * libnetfs/io-select.c (netfs_S_io_select_timeout): Likewise. * libpipe/pipe.c (pipe_pair_select): Add a timeout parameter. * libpipe/pipe.h (pipe_select_readable): Likewise. (pipe_select_writable): Likewise. (pipe_pair_select): Likewise. * libpipe/pq.h: Include . * libtrivfs/io-select.c (trivfs_S_io_select_timeout): New function. * pfinet/glue-include/linux/sched.h: Include . (interruptible_sleep_on): Function removed, replaced with ... (interruptible_sleep_on_timeout): New function. (schedule): Update to use interruptible_sleep_on_timeout. (schedule_timeout): Likewise. * pfinet/io-ops.c (io_select_common): New static function. (S_io_select): Use io_select_common. (S_io_select_timeout): New function which makes use of io_select_common. * pfinet/tunnel.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. * pflocal/connq.c (connq_listen): Replace noblock with a timeout parameter. * pflocal/connq.h: Include . (connq_listen): Update declaration to replace noblock with a timeout parameter. * pflocal/io.c (io_select_common): New static function. (S_io_select): Use io_select_common. (S_io_select_timeout): New function which makes use of io_select_common. * pflocal/socket.c (S_socket_accept): Update call to connq_listen to match new declaration. * storeio/io.c (trivfs_S_io_select_timeout): New function. * term/ptyio.c (pty_io_select): Add a timeout parameter. * term/term.h (pty_io_select): Likewise. * term/users.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. * trans/fifo.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. * trans/firmlink.c (trivfs_S_io_select_timeout): New function. * trans/new-fifo.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. * trans/null.c (trivfs_S_io_select_timeout): New function. * trans/streamio.c (io_select_common): New static function. (trivfs_S_io_select): Use io_select_common. (trivfs_S_io_select_timeout): New function which makes use of io_select_common. --- pfinet/glue-include/linux/sched.h | 15 +++++++------ pfinet/io-ops.c | 44 +++++++++++++++++++++++++++++++-------- pfinet/tunnel.c | 40 ++++++++++++++++++++++++++++------- 3 files changed, 77 insertions(+), 22 deletions(-) (limited to 'pfinet') diff --git a/pfinet/glue-include/linux/sched.h b/pfinet/glue-include/linux/sched.h index aea6c47a..26ab10a8 100644 --- a/pfinet/glue-include/linux/sched.h +++ b/pfinet/glue-include/linux/sched.h @@ -8,6 +8,7 @@ #include #include #include +#include #include "mapped-time.h" @@ -92,12 +93,13 @@ capable(int cap) extern pthread_mutex_t global_lock; -static inline void -interruptible_sleep_on (struct wait_queue **p) +static inline int +interruptible_sleep_on_timeout (struct wait_queue **p, struct timespec *tsp) { pthread_cond_t **condp = (void *) p, *c; int isroot; struct wait_queue **next_wait; + error_t err; c = *condp; if (c == 0) @@ -111,12 +113,13 @@ interruptible_sleep_on (struct wait_queue **p) isroot = current->isroot; /* This is our context that needs switched. */ next_wait = current->next_wait; /* This too, for multiple schedule calls. */ current->next_wait = 0; - if (pthread_hurd_cond_wait_np (c, &global_lock)) + err = pthread_hurd_cond_timedwait_np(c, &global_lock, tsp); + if (err == EINTR) current->signal = 1; /* We got cancelled, mark it for later. */ current->isroot = isroot; /* Switch back to our context. */ current->next_wait = next_wait; + return (err == ETIMEDOUT); } -#define sleep_on interruptible_sleep_on static inline void wake_up_interruptible (struct wait_queue **p) @@ -146,7 +149,7 @@ static inline void schedule (void) { assert (current->next_wait); - interruptible_sleep_on (current->next_wait); + interruptible_sleep_on_timeout (current->next_wait, NULL); } static inline void @@ -171,7 +174,7 @@ schedule_timeout (long timeout) timer.function = process_schedule_timeout; add_timer (&timer); - interruptible_sleep_on (&sleep); + interruptible_sleep_on_timeout (&sleep, NULL); if (signal_pending (current)) { /* We were canceled. */ diff --git a/pfinet/io-ops.c b/pfinet/io-ops.c index 5f3b1e90..69bd93c5 100644 --- a/pfinet/io-ops.c +++ b/pfinet/io-ops.c @@ -251,14 +251,14 @@ S_io_clear_some_openmodes (struct sock_user *user, return 0; } -error_t -S_io_select (struct sock_user *user, - mach_port_t reply, - mach_msg_type_name_t reply_type, - int *select_type) +static error_t +io_select_common (struct sock_user *user, + mach_port_t reply, + mach_msg_type_name_t reply_type, + struct timespec *tsp, int *select_type) { const int want = *select_type | POLLERR; - int avail; + int avail, timedout; int ret = 0; if (!user) @@ -281,9 +281,16 @@ S_io_select (struct sock_user *user, do { - /* Block until we are woken or cancelled. */ - interruptible_sleep_on (user->sock->sk->sleep); - if (signal_pending (current)) /* This means we were cancelled. */ + /* Block until we time out, are woken or cancelled. */ + timedout = interruptible_sleep_on_timeout (user->sock->sk->sleep, + tsp); + if (timedout) + { + __mutex_unlock (&global_lock); + *select_type = 0; + return 0; + } + else if (signal_pending (current)) /* This means we were cancelled. */ { pthread_mutex_unlock (&global_lock); return EINTR; @@ -306,6 +313,25 @@ S_io_select (struct sock_user *user, return ret; } +error_t +S_io_select (struct sock_user *user, + mach_port_t reply, + mach_msg_type_name_t reply_type, + int *select_type) +{ + return io_select_common (user, reply, reply_type, NULL, select_type); +} + +error_t +S_io_select_timeout (struct sock_user *user, + mach_port_t reply, + mach_msg_type_name_t reply_type, + struct timespec ts, + int *select_type) +{ + return io_select_common (user, reply, reply_type, &ts, select_type); +} + error_t S_io_stat (struct sock_user *user, struct stat *st) diff --git a/pfinet/tunnel.c b/pfinet/tunnel.c index 5d2544b2..4a6f616a 100644 --- a/pfinet/tunnel.c +++ b/pfinet/tunnel.c @@ -462,13 +462,14 @@ trivfs_S_io_readable (struct trivfs_protid *cred, return the types that are then available. ID_TAG is returned as passed; it is just for the convenience of the user in matching up reply messages with specific requests sent. */ -error_t -trivfs_S_io_select (struct trivfs_protid *cred, - mach_port_t reply, - mach_msg_type_name_t reply_type, - int *type) +static error_t +io_select_common (struct trivfs_protid *cred, + mach_port_t reply, + mach_msg_type_name_t reply_type, + struct timespec *tsp, int *type) { struct tunnel_device *tdev; + error_t err; if (!cred) return EOPNOTSUPP; @@ -497,15 +498,40 @@ trivfs_S_io_select (struct trivfs_protid *cred, ports_interrupt_self_on_port_death (cred, reply); tdev->read_blocked = 1; - if (pthread_hurd_cond_wait_np (&tdev->select_alert, &tdev->lock)) + err = pthread_hurd_cond_timedwait_np (&tdev->select_alert, &tdev->lock, + tsp); + if (err) { *type = 0; pthread_mutex_unlock (&tdev->lock); - return EINTR; + + if (err == ETIMEDOUT) + err = 0; + + return err; } } } +error_t +trivfs_S_io_select (struct trivfs_protid *cred, + mach_port_t reply, + mach_msg_type_name_t reply_type, + int *type) +{ + return io_select_common (cred, reply, reply_type, NULL, type); +} + +error_t +trivfs_S_io_select_timeout (struct trivfs_protid *cred, + mach_port_t reply, + mach_msg_type_name_t reply_type, + struct timespec ts, + int *type) +{ + return io_select_common (cred, reply, reply_type, &ts, type); +} + /* Change current read/write offset */ error_t trivfs_S_io_seek (struct trivfs_protid *cred, -- cgit v1.2.3