rt-patches/0051-buffer_head-Replace-bh_uptodate_lock-for-rt.patch

   1 From af20f2ae6b96fe1d1981fdad37d5c0a7b80ef8f2 Mon Sep 17 00:00:00 2001
   2 From: Thomas Gleixner <tglx@linutronix.de>
   3 Date: Fri, 18 Mar 2011 09:18:52 +0100
   4 Subject: [PATCH 051/366] buffer_head: Replace bh_uptodate_lock for -rt
   5
   6 Wrap the bit_spin_lock calls into a separate inline and add the RT
   7 replacements with a real spinlock.
   8
   9 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  10 ---
  11  fs/buffer.c                 | 21 +++++++--------------
  12  fs/ntfs/aops.c              | 10 +++-------
  13  include/linux/buffer_head.h | 34 ++++++++++++++++++++++++++++++++++
  14  3 files changed, 44 insertions(+), 21 deletions(-)
  15
  16 diff --git a/fs/buffer.c b/fs/buffer.c
  17 index 4f4cd95..72b27e1 100644
  18 --- a/fs/buffer.c
  19 +++ b/fs/buffer.c
  20 @@ -305,8 +305,7 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
  21          * decide that the page is now completely done.
  22          */
  23         first = page_buffers(page);
  24 -       local_irq_save(flags);
  25 -       bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
  26 +       flags = bh_uptodate_lock_irqsave(first);
  27         clear_buffer_async_read(bh);
  28         unlock_buffer(bh);
  29         tmp = bh;
  30 @@ -319,8 +318,7 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
  31                 }
  32                 tmp = tmp->b_this_page;
  33         } while (tmp != bh);
  34 -       bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
  35 -       local_irq_restore(flags);
  36 +       bh_uptodate_unlock_irqrestore(first, flags);
  37
  38         /*
  39          * If none of the buffers had errors and they are all
  40 @@ -332,9 +330,7 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
  41         return;
  42
  43  still_busy:
  44 -       bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
  45 -       local_irq_restore(flags);
  46 -       return;
  47 +       bh_uptodate_unlock_irqrestore(first, flags);
  48  }
  49
  50  /*
  51 @@ -362,8 +358,7 @@ void end_buffer_async_write(struct buffer_head *bh, int uptodate)
  52         }
  53
  54         first = page_buffers(page);
  55 -       local_irq_save(flags);
  56 -       bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
  57 +       flags = bh_uptodate_lock_irqsave(first);
  58
  59         clear_buffer_async_write(bh);
  60         unlock_buffer(bh);
  61 @@ -375,15 +370,12 @@ void end_buffer_async_write(struct buffer_head *bh, int uptodate)
  62                 }
  63                 tmp = tmp->b_this_page;
  64         }
  65 -       bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
  66 -       local_irq_restore(flags);
  67 +       bh_uptodate_unlock_irqrestore(first, flags);
  68         end_page_writeback(page);
  69         return;
  70
  71  still_busy:
  72 -       bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
  73 -       local_irq_restore(flags);
  74 -       return;
  75 +       bh_uptodate_unlock_irqrestore(first, flags);
  76  }
  77  EXPORT_SYMBOL(end_buffer_async_write);
  78
  79 @@ -3325,6 +3317,7 @@ struct buffer_head *alloc_buffer_head(gfp_t gfp_flags)
  80         struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags);
  81         if (ret) {
  82                 INIT_LIST_HEAD(&ret->b_assoc_buffers);
  83 +               buffer_head_init_locks(ret);
  84                 preempt_disable();
  85                 __this_cpu_inc(bh_accounting.nr);
  86                 recalc_bh_state();
  87 diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
  88 index 7521e11..39b08f5 100644
  89 --- a/fs/ntfs/aops.c
  90 +++ b/fs/ntfs/aops.c
  91 @@ -107,8 +107,7 @@ static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
  92                                 "0x%llx.", (unsigned long long)bh->b_blocknr);
  93         }
  94         first = page_buffers(page);
  95 -       local_irq_save(flags);
  96 -       bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
  97 +       flags = bh_uptodate_lock_irqsave(first);
  98         clear_buffer_async_read(bh);
  99         unlock_buffer(bh);
 100         tmp = bh;
 101 @@ -123,8 +122,7 @@ static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
 102                 }
 103                 tmp = tmp->b_this_page;
 104         } while (tmp != bh);
 105 -       bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
 106 -       local_irq_restore(flags);
 107 +       bh_uptodate_unlock_irqrestore(first, flags);
 108         /*
 109          * If none of the buffers had errors then we can set the page uptodate,
 110          * but we first have to perform the post read mst fixups, if the
 111 @@ -159,9 +157,7 @@ static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
 112         unlock_page(page);
 113         return;
 114  still_busy:
 115 -       bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
 116 -       local_irq_restore(flags);
 117 -       return;
 118 +       bh_uptodate_unlock_irqrestore(first, flags);
 119  }
 120
 121  /**
 122 diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
 123 index 89d9aa9e..ab04527 100644
 124 --- a/include/linux/buffer_head.h
 125 +++ b/include/linux/buffer_head.h
 126 @@ -75,8 +75,42 @@ struct buffer_head {
 127         struct address_space *b_assoc_map;      /* mapping this buffer is
 128                                                    associated with */
 129         atomic_t b_count;               /* users using this buffer_head */
 130 +#ifdef CONFIG_PREEMPT_RT_BASE
 131 +       spinlock_t b_uptodate_lock;
 132 +#endif
 133  };
 134
 135 +static inline unsigned long bh_uptodate_lock_irqsave(struct buffer_head *bh)
 136 +{
 137 +       unsigned long flags;
 138 +
 139 +#ifndef CONFIG_PREEMPT_RT_BASE
 140 +       local_irq_save(flags);
 141 +       bit_spin_lock(BH_Uptodate_Lock, &bh->b_state);
 142 +#else
 143 +       spin_lock_irqsave(&bh->b_uptodate_lock, flags);
 144 +#endif
 145 +       return flags;
 146 +}
 147 +
 148 +static inline void
 149 +bh_uptodate_unlock_irqrestore(struct buffer_head *bh, unsigned long flags)
 150 +{
 151 +#ifndef CONFIG_PREEMPT_RT_BASE
 152 +       bit_spin_unlock(BH_Uptodate_Lock, &bh->b_state);
 153 +       local_irq_restore(flags);
 154 +#else
 155 +       spin_unlock_irqrestore(&bh->b_uptodate_lock, flags);
 156 +#endif
 157 +}
 158 +
 159 +static inline void buffer_head_init_locks(struct buffer_head *bh)
 160 +{
 161 +#ifdef CONFIG_PREEMPT_RT_BASE
 162 +       spin_lock_init(&bh->b_uptodate_lock);
 163 +#endif
 164 +}
 165 +
 166  /*
 167   * macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
 168   * and buffer_foo() functions.
 169 --
 170 1.9.1
 171