mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 15 deletions

diff --git a/drivers/staging/lustre/lustre/obdecho/echo_client.c b/drivers/staging/lustre/lustre/obdecho/echo_client.c
index 64ffe243f8701..1e83669c204d9 100644
--- a/drivers/staging/lustre/lustre/obdecho/echo_client.c
+++ b/drivers/staging/lustre/lustre/obdecho/echo_client.c
@@ -278,7 +278,7 @@ static void echo_page_fini(const struct lu_env *env,
 	struct page *vmpage      = ep->ep_vmpage;
 
 	atomic_dec(&eco->eo_npages);
-	page_cache_release(vmpage);
+	put_page(vmpage);
 }
 
 static int echo_page_prep(const struct lu_env *env,
@@ -373,7 +373,7 @@ static int echo_page_init(const struct lu_env *env, struct cl_object *obj,
 	struct echo_object *eco = cl2echo_obj(obj);
 
 	ep->ep_vmpage = vmpage;
-	page_cache_get(vmpage);
+	get_page(vmpage);
 	mutex_init(&ep->ep_lock);
 	cl_page_slice_add(page, &ep->ep_cl, obj, &echo_page_ops);
 	atomic_inc(&eco->eo_npages);
@@ -1138,7 +1138,7 @@ static int cl_echo_object_brw(struct echo_object *eco, int rw, u64 offset,
 	LASSERT(rc == 0);
 
 	rc = cl_echo_enqueue0(env, eco, offset,
-			      offset + npages * PAGE_CACHE_SIZE - 1,
+			      offset + npages * PAGE_SIZE - 1,
 			      rw == READ ? LCK_PR : LCK_PW, &lh.cookie,
 			      CEF_NEVER);
 	if (rc < 0)
@@ -1311,11 +1311,11 @@ echo_client_page_debug_setup(struct page *page, int rw, u64 id,
 	int      delta;
 
 	/* no partial pages on the client */
-	LASSERT(count == PAGE_CACHE_SIZE);
+	LASSERT(count == PAGE_SIZE);
 
 	addr = kmap(page);
 
-	for (delta = 0; delta < PAGE_CACHE_SIZE; delta += OBD_ECHO_BLOCK_SIZE) {
+	for (delta = 0; delta < PAGE_SIZE; delta += OBD_ECHO_BLOCK_SIZE) {
 		if (rw == OBD_BRW_WRITE) {
 			stripe_off = offset + delta;
 			stripe_id = id;
@@ -1341,11 +1341,11 @@ static int echo_client_page_debug_check(struct page *page, u64 id,
 	int     rc2;
 
 	/* no partial pages on the client */
-	LASSERT(count == PAGE_CACHE_SIZE);
+	LASSERT(count == PAGE_SIZE);
 
 	addr = kmap(page);
 
-	for (rc = delta = 0; delta < PAGE_CACHE_SIZE; delta += OBD_ECHO_BLOCK_SIZE) {
+	for (rc = delta = 0; delta < PAGE_SIZE; delta += OBD_ECHO_BLOCK_SIZE) {
 		stripe_off = offset + delta;
 		stripe_id = id;
 
@@ -1391,7 +1391,7 @@ static int echo_client_kbrw(struct echo_device *ed, int rw, struct obdo *oa,
 		return -EINVAL;
 
 	/* XXX think again with misaligned I/O */
-	npages = count >> PAGE_CACHE_SHIFT;
+	npages = count >> PAGE_SHIFT;
 
 	if (rw == OBD_BRW_WRITE)
 		brw_flags = OBD_BRW_ASYNC;
@@ -1408,7 +1408,7 @@ static int echo_client_kbrw(struct echo_device *ed, int rw, struct obdo *oa,
 
 	for (i = 0, pgp = pga, off = offset;
 	     i < npages;
-	     i++, pgp++, off += PAGE_CACHE_SIZE) {
+	     i++, pgp++, off += PAGE_SIZE) {
 
 		LASSERT(!pgp->pg);      /* for cleanup */
 
@@ -1418,7 +1418,7 @@ static int echo_client_kbrw(struct echo_device *ed, int rw, struct obdo *oa,
 			goto out;
 
 		pages[i] = pgp->pg;
-		pgp->count = PAGE_CACHE_SIZE;
+		pgp->count = PAGE_SIZE;
 		pgp->off = off;
 		pgp->flag = brw_flags;
 
@@ -1473,8 +1473,8 @@ static int echo_client_prep_commit(const struct lu_env *env,
 	if (count <= 0 || (count & (~CFS_PAGE_MASK)) != 0)
 		return -EINVAL;
 
-	npages = batch >> PAGE_CACHE_SHIFT;
-	tot_pages = count >> PAGE_CACHE_SHIFT;
+	npages = batch >> PAGE_SHIFT;
+	tot_pages = count >> PAGE_SHIFT;
 
 	lnb = kcalloc(npages, sizeof(struct niobuf_local), GFP_NOFS);
 	rnb = kcalloc(npages, sizeof(struct niobuf_remote), GFP_NOFS);
@@ -1497,9 +1497,9 @@ static int echo_client_prep_commit(const struct lu_env *env,
 		if (tot_pages < npages)
 			npages = tot_pages;
 
-		for (i = 0; i < npages; i++, off += PAGE_CACHE_SIZE) {
+		for (i = 0; i < npages; i++, off += PAGE_SIZE) {
 			rnb[i].offset = off;
-			rnb[i].len = PAGE_CACHE_SIZE;
+			rnb[i].len = PAGE_SIZE;
 			rnb[i].flags = brw_flags;
 		}
 
@@ -1878,7 +1878,7 @@ static int __init obdecho_init(void)
 {
 	LCONSOLE_INFO("Echo OBD driver; http://www.lustre.org/\n");
 
-	LASSERT(PAGE_CACHE_SIZE % OBD_ECHO_BLOCK_SIZE == 0);
+	LASSERT(PAGE_SIZE % OBD_ECHO_BLOCK_SIZE == 0);
 
 	return echo_client_init();
 }