block: rename BIO_MAX_PAGES to BIO_MAX_VECS

Ever since the addition of multipage bio_vecs BIO_MAX_PAGES has been
horribly confusingly misnamed.  Rename it to BIO_MAX_VECS to stop
confusing users of the bio API.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20210311110137.1132391-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index b048a0e..68a2de6 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -52,7 +52,7 @@ static int fscrypt_zeroout_range_inline_crypt(const struct inode *inode,
 	int num_pages = 0;
 
 	/* This always succeeds since __GFP_DIRECT_RECLAIM is set. */
-	bio = bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
+	bio = bio_alloc(GFP_NOFS, BIO_MAX_VECS);
 
 	while (len) {
 		unsigned int blocks_this_page = min(len, blocks_per_page);
@@ -74,7 +74,7 @@ static int fscrypt_zeroout_range_inline_crypt(const struct inode *inode,
 		len -= blocks_this_page;
 		lblk += blocks_this_page;
 		pblk += blocks_this_page;
-		if (num_pages == BIO_MAX_PAGES || !len ||
+		if (num_pages == BIO_MAX_VECS || !len ||
 		    !fscrypt_mergeable_bio(bio, inode, lblk)) {
 			err = submit_bio_wait(bio);
 			if (err)
@@ -126,7 +126,7 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 		return fscrypt_zeroout_range_inline_crypt(inode, lblk, pblk,
 							  len);
 
-	BUILD_BUG_ON(ARRAY_SIZE(pages) > BIO_MAX_PAGES);
+	BUILD_BUG_ON(ARRAY_SIZE(pages) > BIO_MAX_VECS);
 	nr_pages = min_t(unsigned int, ARRAY_SIZE(pages),
 			 (len + blocks_per_page - 1) >> blocks_per_page_bits);