Hi,
On 06/07/15 08:44, Ming Lin wrote:
From: Kent Overstreet <[email protected]> We can always fill up the bio now, no need to estimate the possible size based on queue parameters.
[snip]
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c index 2c1ae86..64d3116 100644 --- a/fs/gfs2/lops.c +++ b/fs/gfs2/lops.c @@ -261,18 +261,11 @@ void gfs2_log_flush_bio(struct gfs2_sbd *sdp, int rw) static struct bio *gfs2_log_alloc_bio(struct gfs2_sbd *sdp, u64 blkno) { struct super_block *sb = sdp->sd_vfs; - unsigned nrvecs = bio_get_nr_vecs(sb->s_bdev); struct bio *bio;BUG_ON(sdp->sd_log_bio); - while (1) {- bio = bio_alloc(GFP_NOIO, nrvecs); - if (likely(bio)) - break; - nrvecs = max(nrvecs/2, 1U); - } - + bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES); bio->bi_iter.bi_sector = blkno * (sb->s_blocksize >> 9); bio->bi_bdev = sb->s_bdev; bio->bi_end_io = gfs2_end_log_write;
When I wrote this loop I understood that bio_alloc(GFP_NOIO, x) was only guaranteed to be successful in the case x = 1, and that for x > 1, it might return NULL. Does this now mean that for x = BIO_MAX_PAGES it will be guaranteed to never return NULL in this case?
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