Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758718AbXIBCrb (ORCPT ); Sat, 1 Sep 2007 22:47:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754476AbXIBCq7 (ORCPT ); Sat, 1 Sep 2007 22:46:59 -0400 Received: from mail.tor.primus.ca ([216.254.136.21]:48533 "EHLO mail-07.primus.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753659AbXIBCq6 (ORCPT ); Sat, 1 Sep 2007 22:46:58 -0400 From: Matthew Wilcox To: akpm@osdl.org, torvalds@osdl.org Cc: linux-kernel@vger.kernel.org, Matthew Wilcox Subject: [PATCH 4/5] Add lock_page_killable Date: Sat, 1 Sep 2007 22:46:53 -0400 Message-Id: <11887012142366-git-send-email-matthew@wil.cx> X-Mailer: git-send-email 1.4.4.2 In-Reply-To: <20070902024348.GJ14130@parisc-linux.org> References: <20070902024348.GJ14130@parisc-linux.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4508 Lines: 159 and associated infrastructure such as sync_page_killable and fatal_signal_pending. Use lock_page_killable in do_generic_mapping_read() to allow us to kill `cat' of a file on an NFS-mounted filesystem. Signed-off-by: Matthew Wilcox --- include/linux/pagemap.h | 14 ++++++++++++++ include/linux/sched.h | 9 ++++++++- kernel/signal.c | 5 +++++ mm/filemap.c | 25 +++++++++++++++++++++---- 4 files changed, 48 insertions(+), 5 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 8a83537..8b4f533 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -154,6 +154,7 @@ static inline pgoff_t linear_page_index(struct vm_area_struct *vma, } extern void FASTCALL(__lock_page(struct page *page)); +extern int FASTCALL(__lock_page_killable(struct page *page)); extern void FASTCALL(__lock_page_nosync(struct page *page)); extern void FASTCALL(unlock_page(struct page *page)); @@ -168,6 +169,19 @@ static inline void lock_page(struct page *page) } /* + * lock_page_killable is like lock_page but can be interrupted by fatal + * signals. It returns 0 if it locked the page and -EINTR if it was + * killed while waiting. + */ +static inline int lock_page_killable(struct page *page) +{ + might_sleep(); + if (TestSetPageLocked(page)) + return __lock_page_killable(page); + return 0; +} + +/* * lock_page_nosync should only be used if we can't pin the page's inode. * Doesn't play quite so well with block device plugging. */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 6769179..e6f20da 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1769,7 +1769,14 @@ static inline int signal_pending(struct task_struct *p) { return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING)); } - + +extern int FASTCALL(__fatal_signal_pending(struct task_struct *p)); + +static inline int fatal_signal_pending(struct task_struct *p) +{ + return signal_pending(p) && __fatal_signal_pending(p); +} + static inline int need_resched(void) { return unlikely(test_thread_flag(TIF_NEED_RESCHED)); diff --git a/kernel/signal.c b/kernel/signal.c index 986ba10..2b4fe29 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1003,6 +1003,11 @@ void zap_other_threads(struct task_struct *p) } } +int fastcall __fatal_signal_pending(struct task_struct *tsk) +{ + return sigismember(&tsk->pending.signal, SIGKILL); +} + /* * Must be called under rcu_read_lock() or with tasklist_lock read-held. */ diff --git a/mm/filemap.c b/mm/filemap.c index 90b657b..235f092 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -170,6 +170,12 @@ static int sync_page(void *word) return 0; } +static int sync_page_killable(void *word) +{ + sync_page(word); + return fatal_signal_pending(current) ? -EINTR : 0; +} + /** * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range * @mapping: address space structure to write @@ -574,6 +580,14 @@ void fastcall __lock_page(struct page *page) } EXPORT_SYMBOL(__lock_page); +int fastcall __lock_page_killable(struct page *page) +{ + DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); + + return __wait_on_bit_lock(page_waitqueue(page), &wait, + sync_page_killable, TASK_KILLABLE); +} + /* * Variant of lock_page that does not require the caller to hold a reference * on the page's mapping. @@ -975,7 +989,8 @@ page_ok: page_not_up_to_date: /* Get exclusive access to the page ... */ - lock_page(page); + if (lock_page_killable(page)) + goto readpage_eio; /* Did it get truncated before we got the lock? */ if (!page->mapping) { @@ -1003,7 +1018,8 @@ readpage: } if (!PageUptodate(page)) { - lock_page(page); + if (lock_page_killable(page)) + goto readpage_eio; if (!PageUptodate(page)) { if (page->mapping == NULL) { /* @@ -1014,15 +1030,16 @@ readpage: goto find_page; } unlock_page(page); - error = -EIO; shrink_readahead_size_eio(filp, &ra); - goto readpage_error; + goto readpage_eio; } unlock_page(page); } goto page_ok; +readpage_eio: + error = -EIO; readpage_error: /* UHHUH! A synchronous read error occurred. Report it */ desc->error = error; -- 1.4.4.2 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/