[f2fs-dev] [PATCH v2 3/5] Improve compile-time type checking for f2fs_report_zone()

[Bart Van Assche]

Change the type of the third argument of f2fs_report_zone() from void *
into struct blk_zone * to enable type checking.

Signed-off-by: Bart Van Assche <bvanass...@acm.org>
---
 include/f2fs_fs.h   |  4 +++-
 lib/libf2fs_zoned.c | 24 +++++++++++++++---------
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/include/f2fs_fs.h b/include/f2fs_fs.h
index fdbf7c7a0b35..8125e9f8d082 100644
--- a/include/f2fs_fs.h
+++ b/include/f2fs_fs.h
@@ -1560,9 +1560,11 @@ blk_zone_cond_str(struct blk_zone *blkz)
 
 #endif
 
+struct blk_zone;
+
 extern int f2fs_get_zoned_model(int);
 extern int f2fs_get_zone_blocks(int);
-extern int f2fs_report_zone(int, uint64_t, void *);
+extern int f2fs_report_zone(int, uint64_t, struct blk_zone *);
 typedef int (report_zones_cb_t)(int i, void *, void *);
 extern int f2fs_report_zones(int, report_zones_cb_t *, void *);
 extern int f2fs_check_zones(int);
diff --git a/lib/libf2fs_zoned.c b/lib/libf2fs_zoned.c
index d8de66b82029..a0dd8bd269ef 100644
--- a/lib/libf2fs_zoned.c
+++ b/lib/libf2fs_zoned.c
@@ -200,21 +200,26 @@ int f2fs_get_zone_blocks(int i)
        return 0;
 }
 
-int f2fs_report_zone(int i, uint64_t sector, void *blkzone)
+int f2fs_report_zone(int i, uint64_t sector, struct blk_zone *blkzone)
 {
-       struct blk_zone *blkz = (struct blk_zone *)blkzone;
-       struct blk_zone_report *rep;
+       struct one_zone_report {
+               struct blk_zone_report  rep;
+               struct blk_zone         zone;
+       } *rep;
        int ret = -1;
 
-       rep = calloc(1, sizeof(struct blk_zone_report) +
-                    sizeof(struct blk_zone));
+       static_assert(sizeof(*rep) == sizeof(rep->rep) + sizeof(rep->zone), "");
+
+       rep = calloc(1, sizeof(*rep));
        if (!rep) {
                ERR_MSG("No memory for report zones\n");
                return -ENOMEM;
        }
 
-       rep->sector = sector;
-       rep->nr_zones = 1;
+       rep->rep = (struct blk_zone_report){
+               .sector = sector,
+               .nr_zones = 1,
+       };
        ret = ioctl(c.devices[i].fd, BLKREPORTZONE, rep);
        if (ret != 0) {
                ret = -errno;
@@ -222,7 +227,7 @@ int f2fs_report_zone(int i, uint64_t sector, void *blkzone)
                goto out;
        }
 
-       *blkz = *(struct blk_zone *)(rep + 1);
+       *blkzone = rep->zone;
 out:
        free(rep);
        return ret;
@@ -531,7 +536,8 @@ uint32_t f2fs_get_usable_segments(struct f2fs_super_block 
*sb)
 
 #else
 
-int f2fs_report_zone(int i, uint64_t UNUSED(sector), void *UNUSED(blkzone))
+int f2fs_report_zone(int i, uint64_t UNUSED(sector),
+                    struct blk_zone *UNUSED(blkzone))
 {
        ERR_MSG("%d: Unsupported zoned block device\n", i);
        return -1;


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