init android origin source code

1 files changed, 415 insertions, 0 deletions

diff --git a/ANDROID_3.4.5/fs/nfs/pagelist.c b/ANDROID_3.4.5/fs/nfs/pagelist.c
new file mode 100644
index 00000000..d21fceaa
--- /dev/null
+++ b/ANDROID_3.4.5/fs/nfs/pagelist.c
@@ -0,0 +1,415 @@
+/*
+ * linux/fs/nfs/pagelist.c
+ *
+ * A set of helper functions for managing NFS read and write requests.
+ * The main purpose of these routines is to provide support for the
+ * coalescing of several requests into a single RPC call.
+ *
+ * Copyright 2000, 2001 (c) Trond Myklebust <trond.myklebust@fys.uio.no>
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/sched.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfs.h>
+#include <linux/nfs3.h>
+#include <linux/nfs4.h>
+#include <linux/nfs_page.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/export.h>
+
+#include "internal.h"
+#include "pnfs.h"
+
+static struct kmem_cache *nfs_page_cachep;
+
+static inline struct nfs_page *
+nfs_page_alloc(void)
+{
+	struct nfs_page	*p = kmem_cache_zalloc(nfs_page_cachep, GFP_KERNEL);
+	if (p)
+		INIT_LIST_HEAD(&p->wb_list);
+	return p;
+}
+
+static inline void
+nfs_page_free(struct nfs_page *p)
+{
+	kmem_cache_free(nfs_page_cachep, p);
+}
+
+/**
+ * nfs_create_request - Create an NFS read/write request.
+ * @ctx: open context to use
+ * @inode: inode to which the request is attached
+ * @page: page to write
+ * @offset: starting offset within the page for the write
+ * @count: number of bytes to read/write
+ *
+ * The page must be locked by the caller. This makes sure we never
+ * create two different requests for the same page.
+ * User should ensure it is safe to sleep in this function.
+ */
+struct nfs_page *
+nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
+		   struct page *page,
+		   unsigned int offset, unsigned int count)
+{
+	struct nfs_page		*req;
+
+	/* try to allocate the request struct */
+	req = nfs_page_alloc();
+	if (req == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	/* get lock context early so we can deal with alloc failures */
+	req->wb_lock_context = nfs_get_lock_context(ctx);
+	if (req->wb_lock_context == NULL) {
+		nfs_page_free(req);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* Initialize the request struct. Initially, we assume a
+	 * long write-back delay. This will be adjusted in
+	 * update_nfs_request below if the region is not locked. */
+	req->wb_page    = page;
+	atomic_set(&req->wb_complete, 0);
+	req->wb_index	= page->index;
+	page_cache_get(page);
+	BUG_ON(PagePrivate(page));
+	BUG_ON(!PageLocked(page));
+	BUG_ON(page->mapping->host != inode);
+	req->wb_offset  = offset;
+	req->wb_pgbase	= offset;
+	req->wb_bytes   = count;
+	req->wb_context = get_nfs_open_context(ctx);
+	kref_init(&req->wb_kref);
+	return req;
+}
+
+/**
+ * nfs_unlock_request - Unlock request and wake up sleepers.
+ * @req:
+ */
+void nfs_unlock_request(struct nfs_page *req)
+{
+	if (!NFS_WBACK_BUSY(req)) {
+		printk(KERN_ERR "NFS: Invalid unlock attempted\n");
+		BUG();
+	}
+	smp_mb__before_clear_bit();
+	clear_bit(PG_BUSY, &req->wb_flags);
+	smp_mb__after_clear_bit();
+	wake_up_bit(&req->wb_flags, PG_BUSY);
+	nfs_release_request(req);
+}
+
+/*
+ * nfs_clear_request - Free up all resources allocated to the request
+ * @req:
+ *
+ * Release page and open context resources associated with a read/write
+ * request after it has completed.
+ */
+static void nfs_clear_request(struct nfs_page *req)
+{
+	struct page *page = req->wb_page;
+	struct nfs_open_context *ctx = req->wb_context;
+	struct nfs_lock_context *l_ctx = req->wb_lock_context;
+
+	if (page != NULL) {
+		page_cache_release(page);
+		req->wb_page = NULL;
+	}
+	if (l_ctx != NULL) {
+		nfs_put_lock_context(l_ctx);
+		req->wb_lock_context = NULL;
+	}
+	if (ctx != NULL) {
+		put_nfs_open_context(ctx);
+		req->wb_context = NULL;
+	}
+}
+
+
+/**
+ * nfs_release_request - Release the count on an NFS read/write request
+ * @req: request to release
+ *
+ * Note: Should never be called with the spinlock held!
+ */
+static void nfs_free_request(struct kref *kref)
+{
+	struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
+
+	/* Release struct file and open context */
+	nfs_clear_request(req);
+	nfs_page_free(req);
+}
+
+void nfs_release_request(struct nfs_page *req)
+{
+	kref_put(&req->wb_kref, nfs_free_request);
+}
+
+static int nfs_wait_bit_uninterruptible(void *word)
+{
+	io_schedule();
+	return 0;
+}
+
+/**
+ * nfs_wait_on_request - Wait for a request to complete.
+ * @req: request to wait upon.
+ *
+ * Interruptible by fatal signals only.
+ * The user is responsible for holding a count on the request.
+ */
+int
+nfs_wait_on_request(struct nfs_page *req)
+{
+	return wait_on_bit(&req->wb_flags, PG_BUSY,
+			nfs_wait_bit_uninterruptible,
+			TASK_UNINTERRUPTIBLE);
+}
+
+bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, struct nfs_page *prev, struct nfs_page *req)
+{
+	/*
+	 * FIXME: ideally we should be able to coalesce all requests
+	 * that are not block boundary aligned, but currently this
+	 * is problematic for the case of bsize < PAGE_CACHE_SIZE,
+	 * since nfs_flush_multi and nfs_pagein_multi assume you
+	 * can have only one struct nfs_page.
+	 */
+	if (desc->pg_bsize < PAGE_SIZE)
+		return 0;
+
+	return desc->pg_count + req->wb_bytes <= desc->pg_bsize;
+}
+EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
+
+/**
+ * nfs_pageio_init - initialise a page io descriptor
+ * @desc: pointer to descriptor
+ * @inode: pointer to inode
+ * @doio: pointer to io function
+ * @bsize: io block size
+ * @io_flags: extra parameters for the io function
+ */
+void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
+		     struct inode *inode,
+		     const struct nfs_pageio_ops *pg_ops,
+		     size_t bsize,
+		     int io_flags)
+{
+	INIT_LIST_HEAD(&desc->pg_list);
+	desc->pg_bytes_written = 0;
+	desc->pg_count = 0;
+	desc->pg_bsize = bsize;
+	desc->pg_base = 0;
+	desc->pg_moreio = 0;
+	desc->pg_recoalesce = 0;
+	desc->pg_inode = inode;
+	desc->pg_ops = pg_ops;
+	desc->pg_ioflags = io_flags;
+	desc->pg_error = 0;
+	desc->pg_lseg = NULL;
+}
+
+/**
+ * nfs_can_coalesce_requests - test two requests for compatibility
+ * @prev: pointer to nfs_page
+ * @req: pointer to nfs_page
+ *
+ * The nfs_page structures 'prev' and 'req' are compared to ensure that the
+ * page data area they describe is contiguous, and that their RPC
+ * credentials, NFSv4 open state, and lockowners are the same.
+ *
+ * Return 'true' if this is the case, else return 'false'.
+ */
+static bool nfs_can_coalesce_requests(struct nfs_page *prev,
+				      struct nfs_page *req,
+				      struct nfs_pageio_descriptor *pgio)
+{
+	if (req->wb_context->cred != prev->wb_context->cred)
+		return false;
+	if (req->wb_lock_context->lockowner != prev->wb_lock_context->lockowner)
+		return false;
+	if (req->wb_context->state != prev->wb_context->state)
+		return false;
+	if (req->wb_index != (prev->wb_index + 1))
+		return false;
+	if (req->wb_pgbase != 0)
+		return false;
+	if (prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE)
+		return false;
+	return pgio->pg_ops->pg_test(pgio, prev, req);
+}
+
+/**
+ * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
+ * @desc: destination io descriptor
+ * @req: request
+ *
+ * Returns true if the request 'req' was successfully coalesced into the
+ * existing list of pages 'desc'.
+ */
+static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
+				     struct nfs_page *req)
+{
+	if (desc->pg_count != 0) {
+		struct nfs_page *prev;
+
+		prev = nfs_list_entry(desc->pg_list.prev);
+		if (!nfs_can_coalesce_requests(prev, req, desc))
+			return 0;
+	} else {
+		if (desc->pg_ops->pg_init)
+			desc->pg_ops->pg_init(desc, req);
+		desc->pg_base = req->wb_pgbase;
+	}
+	nfs_list_remove_request(req);
+	nfs_list_add_request(req, &desc->pg_list);
+	desc->pg_count += req->wb_bytes;
+	return 1;
+}
+
+/*
+ * Helper for nfs_pageio_add_request and nfs_pageio_complete
+ */
+static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
+{
+	if (!list_empty(&desc->pg_list)) {
+		int error = desc->pg_ops->pg_doio(desc);
+		if (error < 0)
+			desc->pg_error = error;
+		else
+			desc->pg_bytes_written += desc->pg_count;
+	}
+	if (list_empty(&desc->pg_list)) {
+		desc->pg_count = 0;
+		desc->pg_base = 0;
+	}
+}
+
+/**
+ * nfs_pageio_add_request - Attempt to coalesce a request into a page list.
+ * @desc: destination io descriptor
+ * @req: request
+ *
+ * Returns true if the request 'req' was successfully coalesced into the
+ * existing list of pages 'desc'.
+ */
+static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
+			   struct nfs_page *req)
+{
+	while (!nfs_pageio_do_add_request(desc, req)) {
+		desc->pg_moreio = 1;
+		nfs_pageio_doio(desc);
+		if (desc->pg_error < 0)
+			return 0;
+		desc->pg_moreio = 0;
+		if (desc->pg_recoalesce)
+			return 0;
+	}
+	return 1;
+}
+
+static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
+{
+	LIST_HEAD(head);
+
+	do {
+		list_splice_init(&desc->pg_list, &head);
+		desc->pg_bytes_written -= desc->pg_count;
+		desc->pg_count = 0;
+		desc->pg_base = 0;
+		desc->pg_recoalesce = 0;
+
+		while (!list_empty(&head)) {
+			struct nfs_page *req;
+
+			req = list_first_entry(&head, struct nfs_page, wb_list);
+			nfs_list_remove_request(req);
+			if (__nfs_pageio_add_request(desc, req))
+				continue;
+			if (desc->pg_error < 0)
+				return 0;
+			break;
+		}
+	} while (desc->pg_recoalesce);
+	return 1;
+}
+
+int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
+		struct nfs_page *req)
+{
+	int ret;
+
+	do {
+		ret = __nfs_pageio_add_request(desc, req);
+		if (ret)
+			break;
+		if (desc->pg_error < 0)
+			break;
+		ret = nfs_do_recoalesce(desc);
+	} while (ret);
+	return ret;
+}
+
+/**
+ * nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor
+ * @desc: pointer to io descriptor
+ */
+void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
+{
+	for (;;) {
+		nfs_pageio_doio(desc);
+		if (!desc->pg_recoalesce)
+			break;
+		if (!nfs_do_recoalesce(desc))
+			break;
+	}
+}
+
+/**
+ * nfs_pageio_cond_complete - Conditional I/O completion
+ * @desc: pointer to io descriptor
+ * @index: page index
+ *
+ * It is important to ensure that processes don't try to take locks
+ * on non-contiguous ranges of pages as that might deadlock. This
+ * function should be called before attempting to wait on a locked
+ * nfs_page. It will complete the I/O if the page index 'index'
+ * is not contiguous with the existing list of pages in 'desc'.
+ */
+void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
+{
+	if (!list_empty(&desc->pg_list)) {
+		struct nfs_page *prev = nfs_list_entry(desc->pg_list.prev);
+		if (index != prev->wb_index + 1)
+			nfs_pageio_complete(desc);
+	}
+}
+
+int __init nfs_init_nfspagecache(void)
+{
+	nfs_page_cachep = kmem_cache_create("nfs_page",
+					    sizeof(struct nfs_page),
+					    0, SLAB_HWCACHE_ALIGN,
+					    NULL);
+	if (nfs_page_cachep == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void nfs_destroy_nfspagecache(void)
+{
+	kmem_cache_destroy(nfs_page_cachep);
+}
+