From 8c9e80ed276fc4b9c9fadf29d8bf6b3576112f1a Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 21 Apr 2011 17:23:19 -0700 Subject: SECURITY: Move exec_permission RCU checks into security modules Right now all RCU walks fall back to reference walk when CONFIG_SECURITY is enabled, even though just the standard capability module is active. This is because security_inode_exec_permission unconditionally fails RCU walks. Move this decision to the low level security module. This requires passing the RCU flags down the security hook. This way at least the capability module and a few easy cases in selinux/smack work with RCU walks with CONFIG_SECURITY=y Signed-off-by: Andi Kleen Acked-by: Eric Paris Signed-off-by: Linus Torvalds --- include/linux/security.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/security.h b/include/linux/security.h index ca02f1716736..8ce59ef3e5af 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1456,7 +1456,7 @@ struct security_operations { struct inode *new_dir, struct dentry *new_dentry); int (*inode_readlink) (struct dentry *dentry); int (*inode_follow_link) (struct dentry *dentry, struct nameidata *nd); - int (*inode_permission) (struct inode *inode, int mask); + int (*inode_permission) (struct inode *inode, int mask, unsigned flags); int (*inode_setattr) (struct dentry *dentry, struct iattr *attr); int (*inode_getattr) (struct vfsmount *mnt, struct dentry *dentry); int (*inode_setxattr) (struct dentry *dentry, const char *name, -- cgit v1.2.3 From dea3667bc3c2a0521e8d8855e407a49d9d70028c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 24 Apr 2011 07:58:46 -0700 Subject: vfs: get rid of insane dentry hashing rules The dentry hashing rules have been really quite complicated for a long while, in odd ways. That made functions like __d_drop() very fragile and non-obvious. In particular, whether a dentry was hashed or not was indicated with an explicit DCACHE_UNHASHED bit. That's despite the fact that the hash abstraction that the dentries use actually have a 'is this entry hashed or not' model (which is a simple test of the 'pprev' pointer). The reason that was done is because we used the normal 'is this entry unhashed' model to mark whether the dentry had _ever_ been hashed in the dentry hash tables, and that logic goes back many years (commit b3423415fbc2: "dcache: avoid RCU for never-hashed dentries"). That, in turn, meant that __d_drop had totally different unhashing logic for the dentry hash table case and for the anonymous dcache case, because in order to use the "is this dentry hashed" logic as a flag for whether it had ever been on the RCU hash table, we had to unhash such a dentry differently so that we'd never think that it wasn't 'unhashed' and wouldn't be free'd correctly. That's just insane. It made the logic really hard to follow, when there were two different kinds of "unhashed" states, and one of them (the one that used "list_bl_unhashed()") really had nothing at all to do with being unhashed per se, but with a very subtle lifetime rule instead. So turn all of it around, and make it logical. Instead of having a DENTRY_UNHASHED bit in d_flags to indicate whether the dentry is on the hash chains or not, use the hash chain unhashed logic for that. Suddenly "d_unhashed()" just uses "list_bl_unhashed()", and everything makes sense. And for the lifetime rule, just use an explicit DENTRY_RCUACCEES bit. If we ever insert the dentry into the dentry hash table so that it is visible to RCU lookup, we mark it DENTRY_RCUACCESS to show that it now needs the RCU lifetime rules. Now suddently that test at dentry free time makes sense too. And because unhashing now is sane and doesn't depend on where the dentry got unhashed from (because the dentry hash chain details doesn't have some subtle side effects), we can re-unify the __d_drop() logic and use common code for the unhashing. Also fix one more open-coded hash chain bit_spin_lock() that I missed in the previous chain locking cleanup commit. Signed-off-by: Linus Torvalds --- include/linux/dcache.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/dcache.h b/include/linux/dcache.h index f2afed4fa945..19d90a55541d 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -197,7 +197,7 @@ struct dentry_operations { * typically using d_splice_alias. */ #define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */ -#define DCACHE_UNHASHED 0x0010 +#define DCACHE_RCUACCESS 0x0010 /* Entry has ever been RCU-visible */ #define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched by inotify */ @@ -384,7 +384,7 @@ extern struct dentry *dget_parent(struct dentry *dentry); static inline int d_unhashed(struct dentry *dentry) { - return (dentry->d_flags & DCACHE_UNHASHED); + return hlist_bl_unhashed(&dentry->d_hash); } static inline int d_unlinked(struct dentry *dentry) -- cgit v1.2.3 From 3f7ac1d6671ebca7a955853f7127c937f7befbd3 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 16 Mar 2011 11:14:25 +0100 Subject: libata: Kill unused ATA_DFLAG_{H|D}IPM flags ATA_DFLAG_{H|D}IPM flags are no longer used. Kill them. Signed-off-by: Tejun Heo Signed-off-by: Jeff Garzik --- include/linux/libata.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include') diff --git a/include/linux/libata.h b/include/linux/libata.h index 7f675aa81d87..3b4d223a6aff 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -137,8 +137,6 @@ enum { ATA_DFLAG_ACPI_PENDING = (1 << 5), /* ACPI resume action pending */ ATA_DFLAG_ACPI_FAILED = (1 << 6), /* ACPI on devcfg has failed */ ATA_DFLAG_AN = (1 << 7), /* AN configured */ - ATA_DFLAG_HIPM = (1 << 8), /* device supports HIPM */ - ATA_DFLAG_DIPM = (1 << 9), /* device supports DIPM */ ATA_DFLAG_DMADIR = (1 << 10), /* device requires DMADIR */ ATA_DFLAG_CFG_MASK = (1 << 12) - 1, -- cgit v1.2.3 From ae01b2493c3bf03c504c32ac4ebb01d528508db3 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 16 Mar 2011 11:14:55 +0100 Subject: libata: Implement ATA_FLAG_NO_DIPM and apply it to mcp65 NVIDIA mcp65 familiy of controllers cause command timeouts when DIPM is used. Implement ATA_FLAG_NO_DIPM and apply it. This problem was reported by Stefan Bader in the following thread. http://thread.gmane.org/gmane.linux.ide/48841 stable: applicable to 2.6.37 and 38. Signed-off-by: Tejun Heo Reported-by: Stefan Bader Cc: stable@kernel.org Signed-off-by: Jeff Garzik --- include/linux/libata.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/libata.h b/include/linux/libata.h index 3b4d223a6aff..04f32a3eb26b 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -196,6 +196,7 @@ enum { * management */ ATA_FLAG_SW_ACTIVITY = (1 << 22), /* driver supports sw activity * led */ + ATA_FLAG_NO_DIPM = (1 << 23), /* host not happy with DIPM */ /* bits 24:31 of ap->flags are reserved for LLD specific flags */ -- cgit v1.2.3 From 3dd2ee4824b668a635d6d2bb6bc73f33708cab9f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 25 Apr 2011 18:10:58 -0700 Subject: bit_spinlock: don't play preemption games inside the busy loop When we are waiting for the bit-lock to be released, and are looping over the 'cpu_relax()' should not be doing anything else - otherwise we miss the point of trying to do the whole 'cpu_relax()'. Do the preemption enable/disable around the loop, rather than inside of it. Noticed when I was looking at the code generation for the dcache __d_drop usage, and the code just looked very odd. Signed-off-by: Linus Torvalds --- include/linux/bit_spinlock.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/bit_spinlock.h b/include/linux/bit_spinlock.h index e612575a2596..b4326bfa684f 100644 --- a/include/linux/bit_spinlock.h +++ b/include/linux/bit_spinlock.h @@ -23,11 +23,11 @@ static inline void bit_spin_lock(int bitnum, unsigned long *addr) preempt_disable(); #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) while (unlikely(test_and_set_bit_lock(bitnum, addr))) { - while (test_bit(bitnum, addr)) { - preempt_enable(); + preempt_enable(); + do { cpu_relax(); - preempt_disable(); - } + } while (test_bit(bitnum, addr)); + preempt_disable(); } #endif __acquire(bitlock); -- cgit v1.2.3 From 1879fd6a26571fd4e8e1f4bb3e7537bc936b1fe7 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 25 Apr 2011 14:01:36 -0400 Subject: add hlist_bl_lock/unlock helpers Now that the whole dcache_hash_bucket crap is gone, go all the way and also remove the weird locking layering violations for locking the hash buckets. Add hlist_bl_lock/unlock helpers to move the locking into the list abstraction instead of requiring each caller to open code it. After all allowing for the bit locks is the whole point of these helpers over the plain hlist variant. Signed-off-by: Christoph Hellwig Signed-off-by: Linus Torvalds --- include/linux/list_bl.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include') diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h index 5bad17d1acde..31f9d75adc5b 100644 --- a/include/linux/list_bl.h +++ b/include/linux/list_bl.h @@ -2,6 +2,7 @@ #define _LINUX_LIST_BL_H #include +#include /* * Special version of lists, where head of the list has a lock in the lowest @@ -114,6 +115,16 @@ static inline void hlist_bl_del_init(struct hlist_bl_node *n) } } +static inline void hlist_bl_lock(struct hlist_bl_head *b) +{ + bit_spin_lock(0, (unsigned long *)b); +} + +static inline void hlist_bl_unlock(struct hlist_bl_head *b) +{ + __bit_spin_unlock(0, (unsigned long *)b); +} + /** * hlist_bl_for_each_entry - iterate over list of given type * @tpos: the type * to use as a loop cursor. -- cgit v1.2.3