Merge tag 'erofs-for-6.4-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:
 "One patch addresses a null-ptr-deref issue reported by syzbot weeks
  ago, which is caused by the new long xattr name prefix feature and
  needs to be fixed.

  The remaining two patches are minor cleanups to avoid unnecessary
  compilation and adjust per-cpu kworker configuration.

  Summary:

   - Fix null-ptr-deref related to long xattr name prefixes

   - Avoid pcpubuf compilation if CONFIG_EROFS_FS_ZIP is off

   - Use high priority kthreads by default if per-cpu kthread workers
     are enabled"

* tag 'erofs-for-6.4-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: use HIPRI by default if per-cpu kthreads are enabled
  erofs: avoid pcpubuf.c inclusion if CONFIG_EROFS_FS_ZIP is off
  erofs: fix null-ptr-deref caused by erofs_xattr_prefixes_init

Author: torvalds

fs/erofs/Kconfig

@@ -121,6 +121,7 @@ config EROFS_FS_PCPU_KTHREAD
 config EROFS_FS_PCPU_KTHREAD_HIPRI
 	bool "EROFS high priority per-CPU kthread workers"
 	depends on EROFS_FS_ZIP && EROFS_FS_PCPU_KTHREAD
+	default y
 	help
 	  This permits EROFS to configure per-CPU kthread workers to run
 	  at higher priority.

fs/erofs/Makefile

@@ -1,8 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 obj-$(CONFIG_EROFS_FS) += erofs.o
-erofs-objs := super.o inode.o data.o namei.o dir.o utils.o pcpubuf.o sysfs.o
+erofs-objs := super.o inode.o data.o namei.o dir.o utils.o sysfs.o
 erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
-erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o zdata.o
+erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o zdata.o pcpubuf.o
 erofs-$(CONFIG_EROFS_FS_ZIP_LZMA) += decompressor_lzma.o
 erofs-$(CONFIG_EROFS_FS_ONDEMAND) += fscache.o

fs/erofs/internal.h

@@ -472,12 +472,6 @@ static inline void *erofs_vm_map_ram(struct page **pages, unsigned int count)
 	return NULL;
 }
 
-void *erofs_get_pcpubuf(unsigned int requiredpages);
-void erofs_put_pcpubuf(void *ptr);
-int erofs_pcpubuf_growsize(unsigned int nrpages);
-void __init erofs_pcpubuf_init(void);
-void erofs_pcpubuf_exit(void);
-
 int erofs_register_sysfs(struct super_block *sb);
 void erofs_unregister_sysfs(struct super_block *sb);
 int __init erofs_init_sysfs(void);
@@ -512,6 +506,11 @@ int z_erofs_load_lz4_config(struct super_block *sb,
 			    struct z_erofs_lz4_cfgs *lz4, int len);
 int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
 			    int flags);
+void *erofs_get_pcpubuf(unsigned int requiredpages);
+void erofs_put_pcpubuf(void *ptr);
+int erofs_pcpubuf_growsize(unsigned int nrpages);
+void __init erofs_pcpubuf_init(void);
+void erofs_pcpubuf_exit(void);
 #else
 static inline void erofs_shrinker_register(struct super_block *sb) {}
 static inline void erofs_shrinker_unregister(struct super_block *sb) {}
@@ -529,6 +528,8 @@ static inline int z_erofs_load_lz4_config(struct super_block *sb,
 	}
 	return 0;
 }
+static inline void erofs_pcpubuf_init(void) {}
+static inline void erofs_pcpubuf_exit(void) {}
 #endif	/* !CONFIG_EROFS_FS_ZIP */
 
 #ifdef CONFIG_EROFS_FS_ZIP_LZMA

fs/erofs/xattr.c

@@ -675,7 +675,7 @@ int erofs_xattr_prefixes_init(struct super_block *sb)
 	if (!pfs)
 		return -ENOMEM;
 
-	if (erofs_sb_has_fragments(sbi))
+	if (sbi->packed_inode)
 		buf.inode = sbi->packed_inode;
 	else
 		erofs_init_metabuf(&buf, sb);

fs/erofs/zdata.c

@@ -369,8 +369,6 @@ static struct kthread_worker *erofs_init_percpu_worker(int cpu)
 		return worker;
 	if (IS_ENABLED(CONFIG_EROFS_FS_PCPU_KTHREAD_HIPRI))
 		sched_set_fifo_low(worker->task);
-	else
-		sched_set_normal(worker->task, 0);
 	return worker;
 }