Merge tag 'block-5.15-2021-09-11' of git://git.kernel.dk/linux-block

[sfrench/cifs-2.6.git] / block / genhd.c

diff --git a/block/genhd.c b/block/genhd.c
index 567549a011d18cc3f784042969365030222762b4..7b6e5e1cf95642adaa6a6fb53e902b6466d1f0f7 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -183,6 +183,7 @@ static struct blk_major_name {
        void (*probe)(dev_t devt);
 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
 static DEFINE_MUTEX(major_names_lock);
+static DEFINE_SPINLOCK(major_names_spinlock);
 
 /* index in the above - for now: assume no multimajor ranges */
 static inline int major_to_index(unsigned major)
@@ -195,11 +196,11 @@ void blkdev_show(struct seq_file *seqf, off_t offset)
 {
        struct blk_major_name *dp;
 
-       mutex_lock(&major_names_lock);
+       spin_lock(&major_names_spinlock);
        for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
                if (dp->major == offset)
                        seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
-       mutex_unlock(&major_names_lock);
+       spin_unlock(&major_names_spinlock);
 }
 #endif /* CONFIG_PROC_FS */
 
@@ -271,6 +272,7 @@ int __register_blkdev(unsigned int major, const char *name,
        p->next = NULL;
        index = major_to_index(major);
 
+       spin_lock(&major_names_spinlock);
        for (n = &major_names[index]; *n; n = &(*n)->next) {
                if ((*n)->major == major)
                        break;
@@ -279,6 +281,7 @@ int __register_blkdev(unsigned int major, const char *name,
                *n = p;
        else
                ret = -EBUSY;
+       spin_unlock(&major_names_spinlock);
 
        if (ret < 0) {
                printk("register_blkdev: cannot get major %u for %s\n",
@@ -298,6 +301,7 @@ void unregister_blkdev(unsigned int major, const char *name)
        int index = major_to_index(major);
 
        mutex_lock(&major_names_lock);
+       spin_lock(&major_names_spinlock);
        for (n = &major_names[index]; *n; n = &(*n)->next)
                if ((*n)->major == major)
                        break;
@@ -307,6 +311,7 @@ void unregister_blkdev(unsigned int major, const char *name)
                p = *n;
                *n = p->next;
        }
+       spin_unlock(&major_names_spinlock);
        mutex_unlock(&major_names_lock);
        kfree(p);
 }