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Subject[PATCH 15/71] scsi: 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: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
---
drivers/scsi/sd.c | 2 +-
drivers/scsi/st.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 5a5457ac9cdb..1bd0753f678a 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2891,7 +2891,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
if (sdkp->opt_xfer_blocks &&
sdkp->opt_xfer_blocks <= dev_max &&
sdkp->opt_xfer_blocks <= SD_DEF_XFER_BLOCKS &&
- sdkp->opt_xfer_blocks * sdp->sector_size >= PAGE_CACHE_SIZE)
+ sdkp->opt_xfer_blocks * sdp->sector_size >= PAGE_SIZE)
rw_max = q->limits.io_opt =
sdkp->opt_xfer_blocks * sdp->sector_size;
else
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 607b0a505844..0177a9a4849f 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -4943,7 +4943,7 @@ static int sgl_map_user_pages(struct st_buffer *STbp,
out_unmap:
if (res > 0) {
for (j=0; j < res; j++)
- page_cache_release(pages[j]);
+ put_page(pages[j]);
res = 0;
}
kfree(pages);
@@ -4965,7 +4965,7 @@ static int sgl_unmap_user_pages(struct st_buffer *STbp,
/* FIXME: cache flush missing for rw==READ
* FIXME: call the correct reference counting function
*/
- page_cache_release(page);
+ put_page(page);
}
kfree(STbp->mapped_pages);
STbp->mapped_pages = NULL;
--
2.7.0
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