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>

3 files changed, 7 insertions, 7 deletions

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 8c6bc795f060..15612ffa8d57 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1728,8 +1728,8 @@ alloc_enc_pages(struct rpc_rqst *rqstp)
 		return 0;
 	}
 
-	first = snd_buf->page_base >> PAGE_CACHE_SHIFT;
-	last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_CACHE_SHIFT;
+	first = snd_buf->page_base >> PAGE_SHIFT;
+	last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_SHIFT;
 	rqstp->rq_enc_pages_num = last - first + 1 + 1;
 	rqstp->rq_enc_pages
 		= kmalloc(rqstp->rq_enc_pages_num * sizeof(struct page *),
@@ -1775,10 +1775,10 @@ gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
 	status = alloc_enc_pages(rqstp);
 	if (status)
 		return status;
-	first = snd_buf->page_base >> PAGE_CACHE_SHIFT;
+	first = snd_buf->page_base >> PAGE_SHIFT;
 	inpages = snd_buf->pages + first;
 	snd_buf->pages = rqstp->rq_enc_pages;
-	snd_buf->page_base -= first << PAGE_CACHE_SHIFT;
+	snd_buf->page_base -= first << PAGE_SHIFT;
 	/*
 	 * Give the tail its own page, in case we need extra space in the
 	 * head when wrapping:
diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
index d94a8e1e9f05..045e11ecd332 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -465,7 +465,7 @@ encryptor(struct scatterlist *sg, void *data)
 	page_pos = desc->pos - outbuf->head[0].iov_len;
 	if (page_pos >= 0 && page_pos < outbuf->page_len) {
 		/* pages are not in place: */
-		int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
+		int i = (page_pos + outbuf->page_base) >> PAGE_SHIFT;
 		in_page = desc->pages[i];
 	} else {
 		in_page = sg_page(sg);
diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c
index 765088e4ad84..a737c2da0837 100644
--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
@@ -79,9 +79,9 @@ gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
 		len -= buf->head[0].iov_len;
 	if (len <= buf->page_len) {
 		unsigned int last = (buf->page_base + len - 1)
-					>>PAGE_CACHE_SHIFT;
+					>>PAGE_SHIFT;
 		unsigned int offset = (buf->page_base + len - 1)
-					& (PAGE_CACHE_SIZE - 1);
+					& (PAGE_SIZE - 1);
 		ptr = kmap_atomic(buf->pages[last]);
 		pad = *(ptr + offset);
 		kunmap_atomic(ptr);