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Subject[PATCH 2/2] dio: simple cleanup for direct_io_worker()
Date
Use DIV_ROUND_UP() and offset_in_page() to make code simpler.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
---
fs/direct-io.c | 13 ++++++++-----
1 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 8201c2558d85..7ba681412bd4 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1020,16 +1020,19 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
for (seg = 0; seg < nr_segs; seg++) {
user_addr = (unsigned long)iov[seg].iov_base;
dio->pages_in_io +=
- ((user_addr+iov[seg].iov_len +PAGE_SIZE-1)/PAGE_SIZE
+ (DIV_ROUND_UP(user_addr + iov[seg].iov_len, PAGE_SIZE)
- user_addr/PAGE_SIZE);
}

for (seg = 0; seg < nr_segs; seg++) {
+ unsigned page_offset;
+
user_addr = (unsigned long)iov[seg].iov_base;
dio->size += bytes = iov[seg].iov_len;
+ page_offset = offset_in_page(user_addr);

/* Index into the first page of the first block */
- dio->first_block_in_page = (user_addr & ~PAGE_MASK) >> blkbits;
+ dio->first_block_in_page = page_offset >> blkbits;
dio->final_block_in_request = dio->block_in_file +
(bytes >> blkbits);
/* Page fetching state */
@@ -1038,11 +1041,11 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
dio->curr_page = 0;

dio->total_pages = 0;
- if (user_addr & (PAGE_SIZE-1)) {
+ if (page_offset) {
dio->total_pages++;
- bytes -= PAGE_SIZE - (user_addr & (PAGE_SIZE - 1));
+ bytes -= PAGE_SIZE - page_offset;
}
- dio->total_pages += (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
+ dio->total_pages += DIV_ROUND_UP(bytes, PAGE_SIZE);
dio->curr_user_address = user_addr;

ret = do_direct_IO(dio);
--
1.7.3.4.600.g982838b0


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