[PATCH 30/44] fs: use min() or umin() instead of min_t()

[david.laight.linux@gmail.com]

From: David Laight <david.laight.linux@gmail.com>

min_t(unsigned int, a, b) casts an 'unsigned long' to 'unsigned int'.
Use min(a, b) instead as it promotes any 'unsigned int' to 'unsigned long'
and so cannot discard significant bits.

A couple of places need umin() because of loops like:
	nfolios = DIV_ROUND_UP(ret + start, PAGE_SIZE);

	for (i = 0; i < nfolios; i++) {
		struct folio *folio = page_folio(pages[i]);
		...
		unsigned int len = umin(ret, PAGE_SIZE - start);
		...
		ret -= len;
		...
	}
where the compiler doesn't track things well enough to know that
'ret' is never negative.

The alternate loop:
        for (i = 0; ret > 0; i++) {
                struct folio *folio = page_folio(pages[i]);
                ...
                unsigned int len = min(ret, PAGE_SIZE - start);
                ...
                ret -= len;
                ...
        }
would be equivalent and doesn't need 'nfolios'.

Most of the 'unsigned long' actually come from PAGE_SIZE.

Detected by an extra check added to min_t().

Signed-off-by: David Laight <david.laight.linux@gmail.com>
---
 fs/buffer.c       | 2 +-
 fs/exec.c         | 2 +-
 fs/ext4/mballoc.c | 3 +--
 fs/ext4/resize.c  | 2 +-
 fs/ext4/super.c   | 2 +-
 fs/fat/dir.c      | 4 ++--
 fs/fat/file.c     | 3 +--
 fs/fuse/dev.c     | 2 +-
 fs/fuse/file.c    | 8 +++-----
 fs/splice.c       | 2 +-
 10 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 6a8752f7bbed..26c4c760b6c6 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2354,7 +2354,7 @@ bool block_is_partially_uptodate(struct folio *folio, size_t from, size_t count)
 	if (!head)
 		return false;
 	blocksize = head->b_size;
-	to = min_t(unsigned, folio_size(folio) - from, count);
+	to = min(folio_size(folio) - from, count);
 	to = from + to;
 	if (from < blocksize && to > folio_size(folio) - blocksize)
 		return false;
diff --git a/fs/exec.c b/fs/exec.c
index 4298e7e08d5d..6d699e48df82 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -555,7 +555,7 @@ int copy_string_kernel(const char *arg, struct linux_binprm *bprm)
 		return -E2BIG;
 
 	while (len > 0) {
-		unsigned int bytes_to_copy = min_t(unsigned int, len,
+		unsigned int bytes_to_copy = min(len,
 				min_not_zero(offset_in_page(pos), PAGE_SIZE));
 		struct page *page;
 
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 9087183602e4..cb68ea974de6 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4254,8 +4254,7 @@ void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
 		 * get the corresponding group metadata to work with.
 		 * For this we have goto again loop.
 		 */
-		thisgrp_len = min_t(unsigned int, (unsigned int)len,
-			EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff));
+		thisgrp_len = min(len, EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff));
 		clen = EXT4_NUM_B2C(sbi, thisgrp_len);
 
 		if (!ext4_sb_block_valid(sb, NULL, block, thisgrp_len)) {
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 050f26168d97..76842f0957b5 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1479,7 +1479,7 @@ static void ext4_update_super(struct super_block *sb,
 
 	/* Update the global fs size fields */
 	sbi->s_groups_count += flex_gd->count;
-	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
+	sbi->s_blockfile_groups = min(sbi->s_groups_count,
 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
 
 	/* Update the reserved block counts only once the new group is
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 33e7c08c9529..e116fe48ff43 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4830,7 +4830,7 @@ static int ext4_check_geometry(struct super_block *sb,
 		return -EINVAL;
 	}
 	sbi->s_groups_count = blocks_count;
-	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
+	sbi->s_blockfile_groups = min(sbi->s_groups_count,
 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
 	if (((u64)sbi->s_groups_count * sbi->s_inodes_per_group) !=
 	    le32_to_cpu(es->s_inodes_count)) {
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 92b091783966..8375e7fbc1a5 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -1353,7 +1353,7 @@ int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
 
 		/* Fill the long name slots. */
 		for (i = 0; i < long_bhs; i++) {
-			int copy = min_t(int, sb->s_blocksize - offset, size);
+			int copy = umin(sb->s_blocksize - offset, size);
 			memcpy(bhs[i]->b_data + offset, slots, copy);
 			mark_buffer_dirty_inode(bhs[i], dir);
 			offset = 0;
@@ -1364,7 +1364,7 @@ int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
 			err = fat_sync_bhs(bhs, long_bhs);
 		if (!err && i < nr_bhs) {
 			/* Fill the short name slot. */
-			int copy = min_t(int, sb->s_blocksize - offset, size);
+			int copy = umin(sb->s_blocksize - offset, size);
 			memcpy(bhs[i]->b_data + offset, slots, copy);
 			mark_buffer_dirty_inode(bhs[i], dir);
 			if (IS_DIRSYNC(dir))
diff --git a/fs/fat/file.c b/fs/fat/file.c
index 4fc49a614fb8..f48435e586c7 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -140,8 +140,7 @@ static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg)
 	if (copy_from_user(&range, user_range, sizeof(range)))
 		return -EFAULT;
 
-	range.minlen = max_t(unsigned int, range.minlen,
-			     bdev_discard_granularity(sb->s_bdev));
+	range.minlen = max(range.minlen, bdev_discard_granularity(sb->s_bdev));
 
 	err = fat_trim_fs(inode, &range);
 	if (err < 0)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 132f38619d70..0c9fb0db1de1 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1813,7 +1813,7 @@ static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
 			goto out_iput;
 
 		folio_offset = ((index - folio->index) << PAGE_SHIFT) + offset;
-		nr_bytes = min_t(unsigned, num, folio_size(folio) - folio_offset);
+		nr_bytes = min(num, folio_size(folio) - folio_offset);
 		nr_pages = (offset + nr_bytes + PAGE_SIZE - 1) >> PAGE_SHIFT;
 
 		err = fuse_copy_folio(cs, &folio, folio_offset, nr_bytes, 0);
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index f1ef77a0be05..f4ffa559ad26 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1252,10 +1252,8 @@ static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
 static inline unsigned int fuse_wr_pages(loff_t pos, size_t len,
 				     unsigned int max_pages)
 {
-	return min_t(unsigned int,
-		     ((pos + len - 1) >> PAGE_SHIFT) -
-		     (pos >> PAGE_SHIFT) + 1,
-		     max_pages);
+	return min(((pos + len - 1) >> PAGE_SHIFT) - (pos >> PAGE_SHIFT) + 1,
+		   max_pages);
 }
 
 static ssize_t fuse_perform_write(struct kiocb *iocb, struct iov_iter *ii)
@@ -1550,7 +1548,7 @@ static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
 			struct folio *folio = page_folio(pages[i]);
 			unsigned int offset = start +
 				(folio_page_idx(folio, pages[i]) << PAGE_SHIFT);
-			unsigned int len = min_t(unsigned int, ret, PAGE_SIZE - start);
+			unsigned int len = umin(ret, PAGE_SIZE - start);
 
 			ap->descs[ap->num_folios].offset = offset;
 			ap->descs[ap->num_folios].length = len;
diff --git a/fs/splice.c b/fs/splice.c
index f5094b6d00a0..41ce3a4ef74f 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1467,7 +1467,7 @@ static ssize_t iter_to_pipe(struct iov_iter *from,
 
 		n = DIV_ROUND_UP(left + start, PAGE_SIZE);
 		for (i = 0; i < n; i++) {
-			int size = min_t(int, left, PAGE_SIZE - start);
+			int size = umin(left, PAGE_SIZE - start);
 
 			buf.page = pages[i];
 			buf.offset = start;
-- 
2.39.5