NFS: Use wait_on_atomic_t() for unlock after readahead
The use of wait_on_atomic_t() for waiting on I/O to complete before
unlocking allows us to git rid of the NFS_IO_INPROGRESS flag, and thus the
nfs_iocounter's flags member, and finally the nfs_iocounter altogether.
The count of I/O is moved to the lock context, and the counter
increment/decrement functions become simple enough to open-code.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
[Trond: Fix up conflict with existing function nfs_wait_atomic_killable()]
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index eeddbf0..cb7e73b 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -101,53 +101,18 @@
kmem_cache_free(nfs_page_cachep, p);
}
-static void
-nfs_iocounter_inc(struct nfs_io_counter *c)
-{
- atomic_inc(&c->io_count);
-}
-
-static void
-nfs_iocounter_dec(struct nfs_io_counter *c)
-{
- if (atomic_dec_and_test(&c->io_count)) {
- clear_bit(NFS_IO_INPROGRESS, &c->flags);
- smp_mb__after_atomic();
- wake_up_bit(&c->flags, NFS_IO_INPROGRESS);
- }
-}
-
-static int
-__nfs_iocounter_wait(struct nfs_io_counter *c)
-{
- wait_queue_head_t *wq = bit_waitqueue(&c->flags, NFS_IO_INPROGRESS);
- DEFINE_WAIT_BIT(q, &c->flags, NFS_IO_INPROGRESS);
- int ret = 0;
-
- do {
- prepare_to_wait(wq, &q.wait, TASK_KILLABLE);
- set_bit(NFS_IO_INPROGRESS, &c->flags);
- if (atomic_read(&c->io_count) == 0)
- break;
- ret = nfs_wait_bit_killable(&q.key, TASK_KILLABLE);
- } while (atomic_read(&c->io_count) != 0 && !ret);
- finish_wait(wq, &q.wait);
- return ret;
-}
-
/**
* nfs_iocounter_wait - wait for i/o to complete
- * @c: nfs_io_counter to use
+ * @l_ctx: nfs_lock_context with io_counter to use
*
* returns -ERESTARTSYS if interrupted by a fatal signal.
* Otherwise returns 0 once the io_count hits 0.
*/
int
-nfs_iocounter_wait(struct nfs_io_counter *c)
+nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
{
- if (atomic_read(&c->io_count) == 0)
- return 0;
- return __nfs_iocounter_wait(c);
+ return wait_on_atomic_t(&l_ctx->io_count, nfs_wait_atomic_killable,
+ TASK_KILLABLE);
}
/*
@@ -370,7 +335,7 @@
return ERR_CAST(l_ctx);
}
req->wb_lock_context = l_ctx;
- nfs_iocounter_inc(&l_ctx->io_count);
+ atomic_inc(&l_ctx->io_count);
/* Initialize the request struct. Initially, we assume a
* long write-back delay. This will be adjusted in
@@ -431,7 +396,8 @@
req->wb_page = NULL;
}
if (l_ctx != NULL) {
- nfs_iocounter_dec(&l_ctx->io_count);
+ if (atomic_dec_and_test(&l_ctx->io_count))
+ wake_up_atomic_t(&l_ctx->io_count);
nfs_put_lock_context(l_ctx);
req->wb_lock_context = NULL;
}