bio_check_eod() should check partiton size not the whole disk if
bio->bi_partno is non-zero.  Does this by taking the call to bio_check_eod
into blk_partition_remap.

Based on an earlier patch from Jiufei Xue.

Fixes: 74d46992e0d9 ("block: replace bi_bdev with a gendisk pointer and 
partitions index")
Reported-by: Jiufei Xue <jiufei....@linux.alibaba.com>
Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 block/blk-core.c | 99 ++++++++++++++++++++++++--------------------------------
 1 file changed, 43 insertions(+), 56 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 6d82c4f7fadd..5a78f5537087 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2023,7 +2023,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, 
struct bio *bio)
        return BLK_QC_T_NONE;
 }
 
-static void handle_bad_sector(struct bio *bio)
+static void handle_bad_sector(struct bio *bio, sector_t maxsector)
 {
        char b[BDEVNAME_SIZE];
 
@@ -2031,7 +2031,7 @@ static void handle_bad_sector(struct bio *bio)
        printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n",
                        bio_devname(bio, b), bio->bi_opf,
                        (unsigned long long)bio_end_sector(bio),
-                       (long long)get_capacity(bio->bi_disk));
+                       (long long)maxsector);
 }
 
 #ifdef CONFIG_FAIL_MAKE_REQUEST
@@ -2092,66 +2092,57 @@ static noinline int should_fail_bio(struct bio *bio)
 }
 ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO);
 
+/*
+ * Check whether this bio extends beyond the end of the device or partition.
+ * This may well happen - the kernel calls bread() without checking the size of
+ * the device, e.g., when mounting a file system.
+ */
+static inline int bio_check_eod(struct bio *bio, sector_t maxsector)
+{
+       unsigned int nr_sectors = bio_sectors(bio);
+
+       if (nr_sectors && maxsector &&
+           (nr_sectors > maxsector ||
+            bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
+               handle_bad_sector(bio, maxsector);
+               return -EIO;
+       }
+       return 0;
+}
+
 /*
  * Remap block n of partition p to block n+start(p) of the disk.
  */
 static inline int blk_partition_remap(struct bio *bio)
 {
        struct hd_struct *p;
-       int ret = 0;
+       sector_t maxsector = 0;
 
        rcu_read_lock();
        p = __disk_get_part(bio->bi_disk, bio->bi_partno);
-       if (unlikely(!p || should_fail_request(p, bio->bi_iter.bi_size) ||
-                    bio_check_ro(bio, p))) {
-               ret = -EIO;
-               goto out;
-       }
+       if (unlikely(!p))
+               goto out_unlock;
+       if (unlikely(should_fail_request(p, bio->bi_iter.bi_size)))
+               goto out_unlock;
+       if (unlikely(bio_check_ro(bio, p)))
+               goto out_unlock;
 
        /*
         * Zone reset does not include bi_size so bio_sectors() is always 0.
         * Include a test for the reset op code and perform the remap if needed.
         */
-       if (!bio_sectors(bio) && bio_op(bio) != REQ_OP_ZONE_RESET)
-               goto out;
-
-       bio->bi_iter.bi_sector += p->start_sect;
-       bio->bi_partno = 0;
-       trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
-                             bio->bi_iter.bi_sector - p->start_sect);
-
-out:
-       rcu_read_unlock();
-       return ret;
-}
-
-/*
- * Check whether this bio extends beyond the end of the device.
- */
-static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
-{
-       sector_t maxsector;
-
-       if (!nr_sectors)
-               return 0;
-
-       /* Test device or partition size, when known. */
-       maxsector = get_capacity(bio->bi_disk);
-       if (maxsector) {
-               sector_t sector = bio->bi_iter.bi_sector;
-
-               if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
-                       /*
-                        * This may well happen - the kernel calls bread()
-                        * without checking the size of the device, e.g., when
-                        * mounting a device.
-                        */
-                       handle_bad_sector(bio);
-                       return 1;
-               }
+       if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET) {
+               bio->bi_iter.bi_sector += p->start_sect;
+               bio->bi_partno = 0;
+               trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
+                                     bio->bi_iter.bi_sector - p->start_sect);
+               maxsector = part_nr_sects_read(p);
        }
-
-       return 0;
+       rcu_read_unlock();
+       return bio_check_eod(bio, maxsector);
+out_unlock:
+       rcu_read_unlock();
+       return -EIO;
 }
 
 static noinline_for_stack bool
@@ -2164,9 +2155,6 @@ generic_make_request_checks(struct bio *bio)
 
        might_sleep();
 
-       if (bio_check_eod(bio, nr_sectors))
-               goto end_io;
-
        q = bio->bi_disk->queue;
        if (unlikely(!q)) {
                printk(KERN_ERR
@@ -2186,17 +2174,16 @@ generic_make_request_checks(struct bio *bio)
        if (should_fail_bio(bio))
                goto end_io;
 
-       if (!bio->bi_partno) {
-               if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0)))
+       if (bio->bi_partno) {
+               if (unlikely(blk_partition_remap(bio)))
                        goto end_io;
        } else {
-               if (blk_partition_remap(bio))
+               if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0)))
+                       goto end_io;
+               if (unlikely(bio_check_eod(bio, get_capacity(bio->bi_disk))))
                        goto end_io;
        }
 
-       if (bio_check_eod(bio, nr_sectors))
-               goto end_io;
-
        /*
         * Filter flush bio's early so that make_request based
         * drivers without flush support don't have to worry
-- 
2.14.2

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