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Subject[PATCH 28/71] dlm: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
Date
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>;

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

- page_cache_get() -> get_page();

- page_cache_release() -> put_page();

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Christine Caulfield <ccaulfie@redhat.com>
Cc: David Teigland <teigland@redhat.com>
---
fs/dlm/lowcomms.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 00640e70ed7a..1ab012a27d9f 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -640,7 +640,7 @@ static int receive_from_sock(struct connection *con)
con->rx_page = alloc_page(GFP_ATOMIC);
if (con->rx_page == NULL)
goto out_resched;
- cbuf_init(&con->cb, PAGE_CACHE_SIZE);
+ cbuf_init(&con->cb, PAGE_SIZE);
}

/*
@@ -657,7 +657,7 @@ static int receive_from_sock(struct connection *con)
* buffer and the start of the currently used section (cb.base)
*/
if (cbuf_data(&con->cb) >= con->cb.base) {
- iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
+ iov[0].iov_len = PAGE_SIZE - cbuf_data(&con->cb);
iov[1].iov_len = con->cb.base;
iov[1].iov_base = page_address(con->rx_page);
nvec = 2;
@@ -675,7 +675,7 @@ static int receive_from_sock(struct connection *con)
ret = dlm_process_incoming_buffer(con->nodeid,
page_address(con->rx_page),
con->cb.base, con->cb.len,
- PAGE_CACHE_SIZE);
+ PAGE_SIZE);
if (ret == -EBADMSG) {
log_print("lowcomms: addr=%p, base=%u, len=%u, read=%d",
page_address(con->rx_page), con->cb.base,
@@ -1416,7 +1416,7 @@ void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
spin_lock(&con->writequeue_lock);
e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
if ((&e->list == &con->writequeue) ||
- (PAGE_CACHE_SIZE - e->end < len)) {
+ (PAGE_SIZE - e->end < len)) {
e = NULL;
} else {
offset = e->end;
--
2.7.0
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