From 797a796a13df6b84a4791e57306737059b5b2384 Mon Sep 17 00:00:00 2001 From: Hitoshi Mitake Date: Tue, 7 Feb 2012 11:45:33 +0900 Subject: asm-generic: architecture independent readq/writeq for 32bit environment This provides unified readq()/writeq() helper functions for 32-bit drivers. For some cases, readq/writeq without atomicity is harmful, and order of io access has to be specified explicitly. So in this patch, new two header files which contain non-atomic readq/writeq are added. - provides non-atomic readq/ writeq with the order of lower address -> higher address - provides non-atomic readq/ writeq with reversed order This allows us to remove some readq()s that were added drivers when the default non-atomic ones were removed in commit dbee8a0affd5 ("x86: remove 32-bit versions of readq()/writeq()") The drivers which need readq/writeq but can do with the non-atomic ones must add the line: #include /* or hi-lo.h */ But this will be nop in 64-bit environments, and no other #ifdefs are required. So I believe that this patch can solve the problem of 1. driver-specific readq/writeq 2. atomicity and order of io access This patch is tested with building allyesconfig and allmodconfig as ARCH=x86 and ARCH=i386 on top of tip/master. Cc: Kashyap Desai Cc: Len Brown Cc: Ravi Anand Cc: Vikas Chaudhary Cc: Matthew Garrett Cc: Jason Uhlenkott Cc: James Bottomley Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Roland Dreier Cc: James Bottomley Cc: Alan Cox Cc: Matthew Wilcox Cc: Andrew Morton Signed-off-by: Hitoshi Mitake Signed-off-by: Linus Torvalds --- include/asm-generic/io-64-nonatomic-hi-lo.h | 28 ++++++++++++++++++++++++++++ include/asm-generic/io-64-nonatomic-lo-hi.h | 28 ++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+) create mode 100644 include/asm-generic/io-64-nonatomic-hi-lo.h create mode 100644 include/asm-generic/io-64-nonatomic-lo-hi.h (limited to 'include/asm-generic') diff --git a/include/asm-generic/io-64-nonatomic-hi-lo.h b/include/asm-generic/io-64-nonatomic-hi-lo.h new file mode 100644 index 000000000000..a6806a94250d --- /dev/null +++ b/include/asm-generic/io-64-nonatomic-hi-lo.h @@ -0,0 +1,28 @@ +#ifndef _ASM_IO_64_NONATOMIC_HI_LO_H_ +#define _ASM_IO_64_NONATOMIC_HI_LO_H_ + +#include +#include + +#ifndef readq +static inline __u64 readq(const volatile void __iomem *addr) +{ + const volatile u32 __iomem *p = addr; + u32 low, high; + + high = readl(p + 1); + low = readl(p); + + return low + ((u64)high << 32); +} +#endif + +#ifndef writeq +static inline void writeq(__u64 val, volatile void __iomem *addr) +{ + writel(val >> 32, addr + 4); + writel(val, addr); +} +#endif + +#endif /* _ASM_IO_64_NONATOMIC_HI_LO_H_ */ diff --git a/include/asm-generic/io-64-nonatomic-lo-hi.h b/include/asm-generic/io-64-nonatomic-lo-hi.h new file mode 100644 index 000000000000..ca546b1ff8b5 --- /dev/null +++ b/include/asm-generic/io-64-nonatomic-lo-hi.h @@ -0,0 +1,28 @@ +#ifndef _ASM_IO_64_NONATOMIC_LO_HI_H_ +#define _ASM_IO_64_NONATOMIC_LO_HI_H_ + +#include +#include + +#ifndef readq +static inline __u64 readq(const volatile void __iomem *addr) +{ + const volatile u32 __iomem *p = addr; + u32 low, high; + + low = readl(p); + high = readl(p + 1); + + return low + ((u64)high << 32); +} +#endif + +#ifndef writeq +static inline void writeq(__u64 val, volatile void __iomem *addr) +{ + writel(val, addr); + writel(val >> 32, addr + 4); +} +#endif + +#endif /* _ASM_IO_64_NONATOMIC_LO_HI_H_ */ -- cgit v1.2.3 From d80e731ecab420ddcb79ee9d0ac427acbc187b4b Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 24 Feb 2012 20:07:11 +0100 Subject: epoll: introduce POLLFREE to flush ->signalfd_wqh before kfree() This patch is intentionally incomplete to simplify the review. It ignores ep_unregister_pollwait() which plays with the same wqh. See the next change. epoll assumes that the EPOLL_CTL_ADD'ed file controls everything f_op->poll() needs. In particular it assumes that the wait queue can't go away until eventpoll_release(). This is not true in case of signalfd, the task which does EPOLL_CTL_ADD uses its ->sighand which is not connected to the file. This patch adds the special event, POLLFREE, currently only for epoll. It expects that init_poll_funcptr()'ed hook should do the necessary cleanup. Perhaps it should be defined as EPOLLFREE in eventpoll. __cleanup_sighand() is changed to do wake_up_poll(POLLFREE) if ->signalfd_wqh is not empty, we add the new signalfd_cleanup() helper. ep_poll_callback(POLLFREE) simply does list_del_init(task_list). This make this poll entry inconsistent, but we don't care. If you share epoll fd which contains our sigfd with another process you should blame yourself. signalfd is "really special". I simply do not know how we can define the "right" semantics if it used with epoll. The main problem is, epoll calls signalfd_poll() once to establish the connection with the wait queue, after that signalfd_poll(NULL) returns the different/inconsistent results depending on who does EPOLL_CTL_MOD/signalfd_read/etc. IOW: apart from sigmask, signalfd has nothing to do with the file, it works with the current thread. In short: this patch is the hack which tries to fix the symptoms. It also assumes that nobody can take tasklist_lock under epoll locks, this seems to be true. Note: - we do not have wake_up_all_poll() but wake_up_poll() is fine, poll/epoll doesn't use WQ_FLAG_EXCLUSIVE. - signalfd_cleanup() uses POLLHUP along with POLLFREE, we need a couple of simple changes in eventpoll.c to make sure it can't be "lost". Reported-by: Maxime Bizon Cc: Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds --- fs/eventpoll.c | 4 ++++ fs/signalfd.c | 11 +++++++++++ include/asm-generic/poll.h | 2 ++ include/linux/signalfd.h | 5 ++++- kernel/fork.c | 5 ++++- 5 files changed, 25 insertions(+), 2 deletions(-) (limited to 'include/asm-generic') diff --git a/fs/eventpoll.c b/fs/eventpoll.c index aabdfc38cf24..34bbfc6dd8dc 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -842,6 +842,10 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k struct epitem *epi = ep_item_from_wait(wait); struct eventpoll *ep = epi->ep; + /* the caller holds eppoll_entry->whead->lock */ + if ((unsigned long)key & POLLFREE) + list_del_init(&wait->task_list); + spin_lock_irqsave(&ep->lock, flags); /* diff --git a/fs/signalfd.c b/fs/signalfd.c index 492465b451dd..79c1eea98a3a 100644 --- a/fs/signalfd.c +++ b/fs/signalfd.c @@ -30,6 +30,17 @@ #include #include +void signalfd_cleanup(struct sighand_struct *sighand) +{ + wait_queue_head_t *wqh = &sighand->signalfd_wqh; + + if (likely(!waitqueue_active(wqh))) + return; + + /* wait_queue_t->func(POLLFREE) should do remove_wait_queue() */ + wake_up_poll(wqh, POLLHUP | POLLFREE); +} + struct signalfd_ctx { sigset_t sigmask; }; diff --git a/include/asm-generic/poll.h b/include/asm-generic/poll.h index 44bce836d350..9ce7f44aebd2 100644 --- a/include/asm-generic/poll.h +++ b/include/asm-generic/poll.h @@ -28,6 +28,8 @@ #define POLLRDHUP 0x2000 #endif +#define POLLFREE 0x4000 /* currently only for epoll */ + struct pollfd { int fd; short events; diff --git a/include/linux/signalfd.h b/include/linux/signalfd.h index 3ff4961da9b5..247399b2979a 100644 --- a/include/linux/signalfd.h +++ b/include/linux/signalfd.h @@ -61,13 +61,16 @@ static inline void signalfd_notify(struct task_struct *tsk, int sig) wake_up(&tsk->sighand->signalfd_wqh); } +extern void signalfd_cleanup(struct sighand_struct *sighand); + #else /* CONFIG_SIGNALFD */ static inline void signalfd_notify(struct task_struct *tsk, int sig) { } +static inline void signalfd_cleanup(struct sighand_struct *sighand) { } + #endif /* CONFIG_SIGNALFD */ #endif /* __KERNEL__ */ #endif /* _LINUX_SIGNALFD_H */ - diff --git a/kernel/fork.c b/kernel/fork.c index b77fd559c78e..e2cd3e2a5ae8 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -66,6 +66,7 @@ #include #include #include +#include #include #include @@ -935,8 +936,10 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) void __cleanup_sighand(struct sighand_struct *sighand) { - if (atomic_dec_and_test(&sighand->count)) + if (atomic_dec_and_test(&sighand->count)) { + signalfd_cleanup(sighand); kmem_cache_free(sighand_cachep, sighand); + } } -- cgit v1.2.3 From 97a29d59fc222b36bac3ee3a8ae994f65bf7ffdf Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Mon, 30 Jan 2012 10:40:47 -0600 Subject: [PARISC] fix compile break caused by iomap: make IOPORT/PCI mapping functions conditional The problem in commit fea80311a939a746533a6d7e7c3183729d6a3faf Author: Randy Dunlap Date: Sun Jul 24 11:39:14 2011 -0700 iomap: make IOPORT/PCI mapping functions conditional is that if your architecture supplies pci_iomap/pci_iounmap, it expects always to supply them. Adding empty body defitions in the !CONFIG_PCI case, which is what this patch does, breaks the parisc compile because the functions become doubly defined. It took us a while to spot this, because we don't actually build !CONFIG_PCI very often (only if someone is brave enough to test the snake/asp machines). Since the note in the commit log says this is to fix a CONFIG_GENERIC_IOMAP issue (which it does because CONFIG_GENERIC_IOMAP supplies pci_iounmap only if CONFIG_PCI is set), there should actually have been a condition upon this. This should make sure no other architecture's !CONFIG_PCI compile breaks in the same way as parisc. The fix had to be updated to take account of the GENERIC_PCI_IOMAP separation. Reported-by: Rolf Eike Beer Signed-off-by: James Bottomley --- include/asm-generic/iomap.h | 2 +- include/asm-generic/pci_iomap.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/iomap.h b/include/asm-generic/iomap.h index 8a3d4fde2604..6afd7d6a9899 100644 --- a/include/asm-generic/iomap.h +++ b/include/asm-generic/iomap.h @@ -70,7 +70,7 @@ extern void ioport_unmap(void __iomem *); /* Destroy a virtual mapping cookie for a PCI BAR (memory or IO) */ struct pci_dev; extern void pci_iounmap(struct pci_dev *dev, void __iomem *); -#else +#elif defined(CONFIG_GENERIC_IOMAP) struct pci_dev; static inline void pci_iounmap(struct pci_dev *dev, void __iomem *addr) { } diff --git a/include/asm-generic/pci_iomap.h b/include/asm-generic/pci_iomap.h index e58fcf891370..ce37349860fe 100644 --- a/include/asm-generic/pci_iomap.h +++ b/include/asm-generic/pci_iomap.h @@ -25,7 +25,7 @@ extern void __iomem *__pci_ioport_map(struct pci_dev *dev, unsigned long port, #define __pci_ioport_map(dev, port, nr) ioport_map((port), (nr)) #endif -#else +#elif defined(CONFIG_GENERIC_PCI_IOMAP) static inline void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max) { return NULL; -- cgit v1.2.3