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/file.c b/fs/nfs/file.c
index 178ec8d..4ef8f5a 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -756,7 +756,7 @@
l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
if (!IS_ERR(l_ctx)) {
- status = nfs_iocounter_wait(&l_ctx->io_count);
+ status = nfs_iocounter_wait(l_ctx);
nfs_put_lock_context(l_ctx);
if (status < 0)
return status;
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 74fb122..4b63d1b 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -71,19 +71,25 @@
return nfs_fileid_to_ino_t(fattr->fileid);
}
-/**
- * nfs_wait_bit_killable - helper for functions that are sleeping on bit locks
- * @word: long word containing the bit lock
- */
-int nfs_wait_bit_killable(struct wait_bit_key *key, int mode)
+static int nfs_wait_killable(int mode)
{
freezable_schedule_unsafe();
if (signal_pending_state(mode, current))
return -ERESTARTSYS;
return 0;
}
+
+int nfs_wait_bit_killable(struct wait_bit_key *key, int mode)
+{
+ return nfs_wait_killable(mode);
+}
EXPORT_SYMBOL_GPL(nfs_wait_bit_killable);
+int nfs_wait_atomic_killable(atomic_t *p)
+{
+ return nfs_wait_killable(TASK_KILLABLE);
+}
+
/**
* nfs_compat_user_ino64 - returns the user-visible inode number
* @fileid: 64-bit fileid
@@ -699,7 +705,7 @@
l_ctx->lockowner.l_owner = current->files;
l_ctx->lockowner.l_pid = current->tgid;
INIT_LIST_HEAD(&l_ctx->list);
- nfs_iocounter_init(&l_ctx->io_count);
+ atomic_set(&l_ctx->io_count, 0);
}
static struct nfs_lock_context *__nfs_find_lock_context(struct nfs_open_context *ctx)
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index ee81792..4e8cc94 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -238,7 +238,7 @@
struct nfs_pgio_header *hdr,
void (*release)(struct nfs_pgio_header *hdr));
void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos);
-int nfs_iocounter_wait(struct nfs_io_counter *c);
+int nfs_iocounter_wait(struct nfs_lock_context *l_ctx);
extern const struct nfs_pageio_ops nfs_pgio_rw_ops;
struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *);
@@ -252,12 +252,6 @@
struct nfs_pgio_mirror *
nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc);
-static inline void nfs_iocounter_init(struct nfs_io_counter *c)
-{
- c->flags = 0;
- atomic_set(&c->io_count, 0);
-}
-
static inline bool nfs_pgio_has_mirroring(struct nfs_pageio_descriptor *desc)
{
WARN_ON_ONCE(desc->pg_mirror_count < 1);
@@ -386,6 +380,7 @@
extern void nfs_evict_inode(struct inode *);
void nfs_zap_acl_cache(struct inode *inode);
extern int nfs_wait_bit_killable(struct wait_bit_key *key, int mode);
+extern int nfs_wait_atomic_killable(atomic_t *p);
/* super.c */
extern const struct super_operations nfs_sops;
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;
}
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 94828b3..8ba4f71 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1565,14 +1565,6 @@
}
}
-static int nfs_wait_atomic_killable(atomic_t *key)
-{
- if (fatal_signal_pending(current))
- return -ERESTARTSYS;
- freezable_schedule_unsafe();
- return 0;
-}
-
static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
{
return wait_on_atomic_t(&cinfo->rpcs_out,
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 9eee972..196aace 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -60,18 +60,12 @@
pid_t l_pid;
};
-#define NFS_IO_INPROGRESS 0
-struct nfs_io_counter {
- unsigned long flags;
- atomic_t io_count;
-};
-
struct nfs_lock_context {
atomic_t count;
struct list_head list;
struct nfs_open_context *open_context;
struct nfs_lockowner lockowner;
- struct nfs_io_counter io_count;
+ atomic_t io_count;
};
struct nfs4_state;