Hello Wentao Wang,
The patch 5ff9a8687feb: "fat: add FITRIM ioctl for FAT file system"
from Jul 11, 2018, leads to the following static checker warning:
fs/fat/fatent.c:791 fat_trim_fs()
warn: should 'trimmed << sbi->cluster_bits' be a 64 bit type?
fs/fat/fatent.c
702 int fat_trim_fs(struct inode *inode, struct fstrim_range *range)
703 {
704 struct super_block *sb = inode->i_sb;
705 struct msdos_sb_info *sbi = MSDOS_SB(sb);
706 const struct fatent_operations *ops = sbi->fatent_ops;
707 struct fat_entry fatent;
708 u64 ent_start, ent_end, minlen;
709 u32 free = 0, trimmed = 0;
^^^ ^^^^^^^^^^^
710 unsigned long reada_blocks, reada_mask, cur_block = 0;
711 int err = 0;
712
713 /*
714 * FAT data is organized as clusters, trim at the granulary of cluster.
715 *
716 * fstrim_range is in byte, convert vaules to cluster index.
717 * Treat sectors before data region as all used, not to trim them.
718 */
719 ent_start = max_t(u64, range->start>>sbi->cluster_bits, FAT_START_ENT);
720 ent_end = ent_start + (range->len >> sbi->cluster_bits) - 1;
721 minlen = range->minlen >> sbi->cluster_bits;
722
723 if (ent_start >= sbi->max_cluster || range->len < sbi->cluster_size)
724 return -EINVAL;
725 if (ent_end >= sbi->max_cluster)
726 ent_end = sbi->max_cluster - 1;
727
728 reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;
729 reada_mask = reada_blocks - 1;
730
731 fatent_init(&fatent);
732 lock_fat(sbi);
733 fatent_set_entry(&fatent, ent_start);
734 while (fatent.entry <= ent_end) {
735 /* readahead of fat blocks */
736 if ((cur_block & reada_mask) == 0) {
737 unsigned long rest = sbi->fat_length - cur_block;
738 fat_ent_reada(sb, &fatent, min(reada_blocks, rest));
739 }
740 cur_block++;
741
742 err = fat_ent_read_block(sb, &fatent);
743 if (err)
744 goto error;
745 do {
746 if (ops->ent_get(&fatent) == FAT_ENT_FREE) {
747 free++;
748 } else if (free) {
749 if (free >= minlen) {
750 u32 clus = fatent.entry - free;
751
752 err = fat_trim_clusters(sb, clus, free);
753 if (err && err != -EOPNOTSUPP)
754 goto error;
755 if (!err)
756 trimmed += free;
757 err = 0;
758 }
759 free = 0;
760 }
761 } while (fat_ent_next(sbi, &fatent) && fatent.entry <= ent_end);
762
763 if (fatal_signal_pending(current)) {
764 err = -ERESTARTSYS;
765 goto error;
766 }
767
768 if (need_resched()) {
769 fatent_brelse(&fatent);
770 unlock_fat(sbi);
771 cond_resched();
772 lock_fat(sbi);
773 }
774 }
775 /* handle scenario when tail entries are all free */
776 if (free && free >= minlen) {
777 u32 clus = fatent.entry - free;
778
779 err = fat_trim_clusters(sb, clus, free);
780 if (err && err != -EOPNOTSUPP)
781 goto error;
782 if (!err)
783 trimmed += free;
784 err = 0;
785 }
786
787 error:
788 fatent_brelse(&fatent);
789 unlock_fat(sbi);
790
791 range->len = trimmed << sbi->cluster_bits;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Potential shift wrap? "range->len" is a u64 but we only use the bottom
32 bits.
792
793 return err;
794 }
regards,
dan carpenter
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