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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-02-10 17:05:52 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-02-10 17:05:52 (GMT) |
commit | af5feae3d7e821d8c4d38103a7f53146f2590892 (patch) | |
tree | 9017bb0661fb617177534f0617c3771d89e31afc | |
parent | ce2814f227d3adae8456f7cbd0bd5f922fd284f0 (diff) | |
parent | 977b7e3a52a7421ad33a393a38ece59f3d41c2fa (diff) | |
download | linux-af5feae3d7e821d8c4d38103a7f53146f2590892.tar.xz |
Merge tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
fix 1 mysterious divide error
fix 3 NULL dereference bugs in writeback tracing, on SD card removal w/o umount
* tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: fix dereferencing NULL bdi->dev on trace_writeback_queue
lib: proportion: lower PROP_MAX_SHIFT to 32 on 64-bit kernel
writeback: fix NULL bdi->dev in trace writeback_single_inode
backing-dev: fix wakeup timer races with bdi_unregister()
-rw-r--r-- | fs/fs-writeback.c | 16 | ||||
-rw-r--r-- | include/linux/proportions.h | 4 | ||||
-rw-r--r-- | include/trace/events/writeback.h | 7 | ||||
-rw-r--r-- | mm/backing-dev.c | 23 |
4 files changed, 35 insertions, 15 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index f855916..5b4a936 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -53,14 +53,6 @@ struct wb_writeback_work { }; /* - * Include the creation of the trace points after defining the - * wb_writeback_work structure so that the definition remains local to this - * file. - */ -#define CREATE_TRACE_POINTS -#include <trace/events/writeback.h> - -/* * We don't actually have pdflush, but this one is exported though /proc... */ int nr_pdflush_threads; @@ -92,6 +84,14 @@ static inline struct inode *wb_inode(struct list_head *head) return list_entry(head, struct inode, i_wb_list); } +/* + * Include the creation of the trace points after defining the + * wb_writeback_work structure and inline functions so that the definition + * remains local to this file. + */ +#define CREATE_TRACE_POINTS +#include <trace/events/writeback.h> + /* Wakeup flusher thread or forker thread to fork it. Requires bdi->wb_lock. */ static void bdi_wakeup_flusher(struct backing_dev_info *bdi) { diff --git a/include/linux/proportions.h b/include/linux/proportions.h index ef35bb7..26a8a4e 100644 --- a/include/linux/proportions.h +++ b/include/linux/proportions.h @@ -81,7 +81,11 @@ void prop_inc_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl) * Limit the time part in order to ensure there are some bits left for the * cycle counter and fraction multiply. */ +#if BITS_PER_LONG == 32 #define PROP_MAX_SHIFT (3*BITS_PER_LONG/4) +#else +#define PROP_MAX_SHIFT (BITS_PER_LONG/2) +#endif #define PROP_FRAC_SHIFT (BITS_PER_LONG - PROP_MAX_SHIFT - 1) #define PROP_FRAC_BASE (1UL << PROP_FRAC_SHIFT) diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h index 8588a89..5973410 100644 --- a/include/trace/events/writeback.h +++ b/include/trace/events/writeback.h @@ -47,7 +47,10 @@ DECLARE_EVENT_CLASS(writeback_work_class, __field(int, reason) ), TP_fast_assign( - strncpy(__entry->name, dev_name(bdi->dev), 32); + struct device *dev = bdi->dev; + if (!dev) + dev = default_backing_dev_info.dev; + strncpy(__entry->name, dev_name(dev), 32); __entry->nr_pages = work->nr_pages; __entry->sb_dev = work->sb ? work->sb->s_dev : 0; __entry->sync_mode = work->sync_mode; @@ -426,7 +429,7 @@ DECLARE_EVENT_CLASS(writeback_single_inode_template, TP_fast_assign( strncpy(__entry->name, - dev_name(inode->i_mapping->backing_dev_info->dev), 32); + dev_name(inode_to_bdi(inode)->dev), 32); __entry->ino = inode->i_ino; __entry->state = inode->i_state; __entry->dirtied_when = inode->dirtied_when; diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 7ba8fea..dd8e2aa 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -318,7 +318,7 @@ static void wakeup_timer_fn(unsigned long data) if (bdi->wb.task) { trace_writeback_wake_thread(bdi); wake_up_process(bdi->wb.task); - } else { + } else if (bdi->dev) { /* * When bdi tasks are inactive for long time, they are killed. * In this case we have to wake-up the forker thread which @@ -584,6 +584,8 @@ EXPORT_SYMBOL(bdi_register_dev); */ static void bdi_wb_shutdown(struct backing_dev_info *bdi) { + struct task_struct *task; + if (!bdi_cap_writeback_dirty(bdi)) return; @@ -602,8 +604,13 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi) * Finally, kill the kernel thread. We don't need to be RCU * safe anymore, since the bdi is gone from visibility. */ - if (bdi->wb.task) - kthread_stop(bdi->wb.task); + spin_lock_bh(&bdi->wb_lock); + task = bdi->wb.task; + bdi->wb.task = NULL; + spin_unlock_bh(&bdi->wb_lock); + + if (task) + kthread_stop(task); } /* @@ -623,7 +630,9 @@ static void bdi_prune_sb(struct backing_dev_info *bdi) void bdi_unregister(struct backing_dev_info *bdi) { - if (bdi->dev) { + struct device *dev = bdi->dev; + + if (dev) { bdi_set_min_ratio(bdi, 0); trace_writeback_bdi_unregister(bdi); bdi_prune_sb(bdi); @@ -632,8 +641,12 @@ void bdi_unregister(struct backing_dev_info *bdi) if (!bdi_cap_flush_forker(bdi)) bdi_wb_shutdown(bdi); bdi_debug_unregister(bdi); - device_unregister(bdi->dev); + + spin_lock_bh(&bdi->wb_lock); bdi->dev = NULL; + spin_unlock_bh(&bdi->wb_lock); + + device_unregister(dev); } } EXPORT_SYMBOL(bdi_unregister); |