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authorSong Liu <songliubraving@fb.com>2016-11-17 15:24:37 -0800
committerShaohua Li <shli@fb.com>2016-11-18 13:25:40 -0800
commit937621c36e0ea1af2aceeaea412ba3bd80247199 (patch)
treef0fdbd7b0912f7d9180a0912ec7e72a5995a6b24 /drivers/md/raid5.h
parentc757ec95c22036b1cb85c56ede368bf8f6c08658 (diff)
md/r5cache: move some code to raid5.h
Move some define and inline functions to raid5.h, so they can be used in raid5-cache.c Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5.h')
-rw-r--r--drivers/md/raid5.h77
1 files changed, 77 insertions, 0 deletions
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 57ec49f0839e..ffc13c4d7e63 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -410,6 +410,83 @@ struct disk_info {
struct md_rdev *rdev, *replacement;
};
+/*
+ * Stripe cache
+ */
+
+#define NR_STRIPES 256
+#define STRIPE_SIZE PAGE_SIZE
+#define STRIPE_SHIFT (PAGE_SHIFT - 9)
+#define STRIPE_SECTORS (STRIPE_SIZE>>9)
+#define IO_THRESHOLD 1
+#define BYPASS_THRESHOLD 1
+#define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
+#define HASH_MASK (NR_HASH - 1)
+#define MAX_STRIPE_BATCH 8
+
+/* bio's attached to a stripe+device for I/O are linked together in bi_sector
+ * order without overlap. There may be several bio's per stripe+device, and
+ * a bio could span several devices.
+ * When walking this list for a particular stripe+device, we must never proceed
+ * beyond a bio that extends past this device, as the next bio might no longer
+ * be valid.
+ * This function is used to determine the 'next' bio in the list, given the
+ * sector of the current stripe+device
+ */
+static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
+{
+ int sectors = bio_sectors(bio);
+
+ if (bio->bi_iter.bi_sector + sectors < sector + STRIPE_SECTORS)
+ return bio->bi_next;
+ else
+ return NULL;
+}
+
+/*
+ * We maintain a biased count of active stripes in the bottom 16 bits of
+ * bi_phys_segments, and a count of processed stripes in the upper 16 bits
+ */
+static inline int raid5_bi_processed_stripes(struct bio *bio)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+
+ return (atomic_read(segments) >> 16) & 0xffff;
+}
+
+static inline int raid5_dec_bi_active_stripes(struct bio *bio)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+
+ return atomic_sub_return(1, segments) & 0xffff;
+}
+
+static inline void raid5_inc_bi_active_stripes(struct bio *bio)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+
+ atomic_inc(segments);
+}
+
+static inline void raid5_set_bi_processed_stripes(struct bio *bio,
+ unsigned int cnt)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ int old, new;
+
+ do {
+ old = atomic_read(segments);
+ new = (old & 0xffff) | (cnt << 16);
+ } while (atomic_cmpxchg(segments, old, new) != old);
+}
+
+static inline void raid5_set_bi_stripes(struct bio *bio, unsigned int cnt)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+
+ atomic_set(segments, cnt);
+}
+
/* NOTE NR_STRIPE_HASH_LOCKS must remain below 64.
* This is because we sometimes take all the spinlocks
* and creating that much locking depth can cause