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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-11-18 14:28:24 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-03-28 13:21:08 +0100 |
| commit | f1e67e355c2aafeddf1eac31335709236996d2fe (patch) | |
| tree | 6405dfe9656d09114a8aec1c87cffe170fc6dec9 /fs/ext4/page-io.c | |
| parent | fc32150e6f43d6cb93ea75937bb6a88a1764cc37 (diff) | |
| download | linux-rpi-f1e67e355c2aafeddf1eac31335709236996d2fe.tar.gz linux-rpi-f1e67e355c2aafeddf1eac31335709236996d2fe.tar.bz2 linux-rpi-f1e67e355c2aafeddf1eac31335709236996d2fe.zip | |
fs/buffer: Make BH_Uptodate_Lock bit_spin_lock a regular spinlock_t
Bit spinlocks are problematic if PREEMPT_RT is enabled, because they
disable preemption, which is undesired for latency reasons and breaks when
regular spinlocks are taken within the bit_spinlock locked region because
regular spinlocks are converted to 'sleeping spinlocks' on RT.
PREEMPT_RT replaced the bit spinlocks with regular spinlocks to avoid this
problem. The replacement was done conditionaly at compile time, but
Christoph requested to do an unconditional conversion.
Jan suggested to move the spinlock into a existing padding hole which
avoids a size increase of struct buffer_head on production kernels.
As a benefit the lock gains lockdep coverage.
[ bigeasy: Remove the wrapper and use always spinlock_t and move it into
the padding hole ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Link: https://lkml.kernel.org/r/20191118132824.rclhrbujqh4b4g4d@linutronix.de
Diffstat (limited to 'fs/ext4/page-io.c')
| -rw-r--r-- | fs/ext4/page-io.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 68b39e75446a..de6fe969f773 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -125,11 +125,10 @@ static void ext4_finish_bio(struct bio *bio) } bh = head = page_buffers(page); /* - * We check all buffers in the page under BH_Uptodate_Lock + * We check all buffers in the page under b_uptodate_lock * to avoid races with other end io clearing async_write flags */ - local_irq_save(flags); - bit_spin_lock(BH_Uptodate_Lock, &head->b_state); + spin_lock_irqsave(&head->b_uptodate_lock, flags); do { if (bh_offset(bh) < bio_start || bh_offset(bh) + bh->b_size > bio_end) { @@ -141,8 +140,7 @@ static void ext4_finish_bio(struct bio *bio) if (bio->bi_status) buffer_io_error(bh); } while ((bh = bh->b_this_page) != head); - bit_spin_unlock(BH_Uptodate_Lock, &head->b_state); - local_irq_restore(flags); + spin_unlock_irqrestore(&head->b_uptodate_lock, flags); if (!under_io) { fscrypt_free_bounce_page(bounce_page); end_page_writeback(page); |