xfs: combine grant heads into a single 64 bit integer
Prepare for switching the grant heads to atomic variables by
combining the two 32 bit values that make up the grant head into a
single 64 bit variable. Provide wrapper functions to combine and
split the grant heads appropriately for calculations and use them as
necessary.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index a5b3c02..2f74c80 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -518,10 +518,8 @@
spinlock_t l_grant_lock ____cacheline_aligned_in_smp;
struct list_head l_reserveq;
struct list_head l_writeq;
- int l_grant_reserve_cycle;
- int l_grant_reserve_bytes;
- int l_grant_write_cycle;
- int l_grant_write_bytes;
+ int64_t l_grant_reserve_head;
+ int64_t l_grant_write_head;
/* The following field are used for debugging; need to hold icloglock */
#ifdef DEBUG
@@ -561,6 +559,26 @@
xlog_in_core_t **commit_iclog, uint flags);
/*
+ * When we crack the grrant head, we sample it first so that the value will not
+ * change while we are cracking it into the component values. This means we
+ * will always get consistent component values to work from.
+ */
+static inline void
+xlog_crack_grant_head(int64_t *head, int *cycle, int *space)
+{
+ int64_t val = *head;
+
+ *cycle = val >> 32;
+ *space = val & 0xffffffff;
+}
+
+static inline void
+xlog_assign_grant_head(int64_t *head, int cycle, int space)
+{
+ *head = ((int64_t)cycle << 32) | space;
+}
+
+/*
* Committed Item List interfaces
*/
int xlog_cil_init(struct log *log);