~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/reiserfs/lock.c

Version: ~ [ linux-5.16-rc3 ] ~ [ linux-5.15.5 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.82 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.162 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.218 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.256 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.291 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.293 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0
  2 #include "reiserfs.h"
  3 #include <linux/mutex.h>
  4 
  5 /*
  6  * The previous reiserfs locking scheme was heavily based on
  7  * the tricky properties of the Bkl:
  8  *
  9  * - it was acquired recursively by a same task
 10  * - the performances relied on the release-while-schedule() property
 11  *
 12  * Now that we replace it by a mutex, we still want to keep the same
 13  * recursive property to avoid big changes in the code structure.
 14  * We use our own lock_owner here because the owner field on a mutex
 15  * is only available in SMP or mutex debugging, also we only need this field
 16  * for this mutex, no need for a system wide mutex facility.
 17  *
 18  * Also this lock is often released before a call that could block because
 19  * reiserfs performances were partially based on the release while schedule()
 20  * property of the Bkl.
 21  */
 22 void reiserfs_write_lock(struct super_block *s)
 23 {
 24         struct reiserfs_sb_info *sb_i = REISERFS_SB(s);
 25 
 26         if (sb_i->lock_owner != current) {
 27                 mutex_lock(&sb_i->lock);
 28                 sb_i->lock_owner = current;
 29         }
 30 
 31         /* No need to protect it, only the current task touches it */
 32         sb_i->lock_depth++;
 33 }
 34 
 35 void reiserfs_write_unlock(struct super_block *s)
 36 {
 37         struct reiserfs_sb_info *sb_i = REISERFS_SB(s);
 38 
 39         /*
 40          * Are we unlocking without even holding the lock?
 41          * Such a situation must raise a BUG() if we don't want
 42          * to corrupt the data.
 43          */
 44         BUG_ON(sb_i->lock_owner != current);
 45 
 46         if (--sb_i->lock_depth == -1) {
 47                 sb_i->lock_owner = NULL;
 48                 mutex_unlock(&sb_i->lock);
 49         }
 50 }
 51 
 52 int __must_check reiserfs_write_unlock_nested(struct super_block *s)
 53 {
 54         struct reiserfs_sb_info *sb_i = REISERFS_SB(s);
 55         int depth;
 56 
 57         /* this can happen when the lock isn't always held */
 58         if (sb_i->lock_owner != current)
 59                 return -1;
 60 
 61         depth = sb_i->lock_depth;
 62 
 63         sb_i->lock_depth = -1;
 64         sb_i->lock_owner = NULL;
 65         mutex_unlock(&sb_i->lock);
 66 
 67         return depth;
 68 }
 69 
 70 void reiserfs_write_lock_nested(struct super_block *s, int depth)
 71 {
 72         struct reiserfs_sb_info *sb_i = REISERFS_SB(s);
 73 
 74         /* this can happen when the lock isn't always held */
 75         if (depth == -1)
 76                 return;
 77 
 78         mutex_lock(&sb_i->lock);
 79         sb_i->lock_owner = current;
 80         sb_i->lock_depth = depth;
 81 }
 82 
 83 /*
 84  * Utility function to force a BUG if it is called without the superblock
 85  * write lock held.  caller is the string printed just before calling BUG()
 86  */
 87 void reiserfs_check_lock_depth(struct super_block *sb, char *caller)
 88 {
 89         struct reiserfs_sb_info *sb_i = REISERFS_SB(sb);
 90 
 91         WARN_ON(sb_i->lock_depth < 0);
 92 }
 93 
 94 #ifdef CONFIG_REISERFS_CHECK
 95 void reiserfs_lock_check_recursive(struct super_block *sb)
 96 {
 97         struct reiserfs_sb_info *sb_i = REISERFS_SB(sb);
 98 
 99         WARN_ONCE((sb_i->lock_depth > 0), "Unwanted recursive reiserfs lock!\n");
100 }
101 #endif
102 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp