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Subject[PATCH] block: factor out bio_check_eod()
End of device check is done twice in __generic_make_request() and it's
fully inlined each time. Factor out bio_check_eod().

This is taken from Jens' zero-length barrier patch.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
---
block/ll_rw_blk.c | 63 ++++++++++++++++++++++++++++--------------------------
1 file changed, 33 insertions(+), 30 deletions(-)

Index: work/block/ll_rw_blk.c
===================================================================
--- work.orig/block/ll_rw_blk.c
+++ work/block/ll_rw_blk.c
@@ -3094,6 +3094,35 @@ static inline int should_fail_request(st

#endif /* CONFIG_FAIL_MAKE_REQUEST */

+/*
+ * Check whether this bio extends beyond the end of the device.
+ */
+static int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
+{
+ sector_t maxsector;
+
+ if (!nr_sectors)
+ return 0;
+
+ /* Test device or partition size, when known. */
+ maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
+ if (maxsector) {
+ sector_t sector = bio->bi_sector;
+
+ if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
+ /*
+ * This may well happen - the kernel calls bread()
+ * without checking the size of the device, e.g., when
+ * mounting a device.
+ */
+ handle_bad_sector(bio);
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
/**
* generic_make_request: hand a buffer to its device driver for I/O
* @bio: The bio describing the location in memory and on the device.
@@ -3121,27 +3150,14 @@ static inline int should_fail_request(st
static inline void __generic_make_request(struct bio *bio)
{
request_queue_t *q;
- sector_t maxsector;
sector_t old_sector;
int ret, nr_sectors = bio_sectors(bio);
dev_t old_dev;

might_sleep();
- /* Test device or partition size, when known. */
- maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
- if (maxsector) {
- sector_t sector = bio->bi_sector;

- if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
- /*
- * This may well happen - the kernel calls bread()
- * without checking the size of the device, e.g., when
- * mounting a device.
- */
- handle_bad_sector(bio);
- goto end_io;
- }
- }
+ if (bio_check_eod(bio, nr_sectors))
+ goto end_io;

/*
* Resolve the mapping until finished. (drivers are
@@ -3197,21 +3213,8 @@ end_io:
old_sector = bio->bi_sector;
old_dev = bio->bi_bdev->bd_dev;

- maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
- if (maxsector) {
- sector_t sector = bio->bi_sector;
-
- if (maxsector < nr_sectors ||
- maxsector - nr_sectors < sector) {
- /*
- * This may well happen - partitions are not
- * checked to make sure they are within the size
- * of the whole device.
- */
- handle_bad_sector(bio);
- goto end_io;
- }
- }
+ if (bio_check_eod(bio, nr_sectors))
+ goto end_io;

ret = q->make_request_fn(q, bio);
} while (ret);
-
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